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1
Allen, Sally Lyman, Dawn Zeilinger, and Eduardo Orias. "Mapping Three Classical Isozyme Loci in Tetrahymena: Meiotic Linkage of EstA to the ChxA Linkage Group." Genetics 144, no. 4 (1996): 1489–96. http://dx.doi.org/10.1093/genetics/144.4.1489.
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We demonstrate a reliable method for mapping conventional loci and obtaining meiotic linkage data for the ciliated protozoan Tetrahymena thermophila. By coupling nullisomic deletion mapping with meiotic linkage mapping, loci known to be located on a particular chromosome or chromosome arm can be tested for recombination. This approach has been used to map three isozyme loci, EstA (Esterase A), EstB (Esterase B), and AcpA (Acid Phosphatase A), with respect to the ChxA locus (cycloheximide resistance) and 11 RAPDs (randomly amplified polymorphic DNAs). To assign isozyme loci to chromosomes, clones of inbred strains C3 or C2 were crossed to inbred strain B nullisomics. EstA, EstB and AcpA were mapped to chromosomes 1R, 3L and 3R, respectively. To test EstA and AcpA for linkage to known RAPD loci on their respective chromosomes, a panel of Round II (genomic exclusion) segregants from a B/C3 heterozygote was used. Using the MAPMAKER program, EstA was assigned to the ChxA linkage group on chromosome IR, and a detailed map was constructed that includes 10 RAPDs. AcpA (on 3R), while unlinked to all the RAPDs assigned to chromosome 3 by nullisomic mapping, does show linkage to a RAPD not yet assignable to chromosomes by nullisomic mapping.
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Nelson, J. C., M. E. Sorrells, A. E. Van Deynze, et al. "Molecular mapping of wheat: major genes and rearrangements in homoeologous groups 4, 5, and 7." Genetics 141, no. 2 (1995): 721–31. http://dx.doi.org/10.1093/genetics/141.2.721.
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Abstract A molecular-marker linkage map of hexaploid wheat (Triticum aestivum L. em. Thell) provides a framework for integration with teh classical genetic map and a record of the chromosomal rearrangements involved in the evolution of this crop species. We have constructed restriction fragment length polymorphism (RFLP) maps of the A-, B-, and D-genome chromosomes of homoeologous groups 4, 5, and 7 of wheat using 114 F7 lines from a synthetic X cultivated wheat cross and clones from 10 DNA libraries. Chromosomal breakpoints for known ancestral reciprocal translocations involving these chromosomes and for a known pericentric inversion on chromosome 4A were localized by linkage and aneuploid analysis. Known genes mapped include the major vernalization genes Vrn1 and Vrn3 on chromosome arms 5AL and 5DL, the red-coleoptile gene Rc1 on 7AS, and presumptively the leaf-rust (Puccinia recondita f.sp. tritici) resistance gene Lr34 on 7DS and the kernel-hardness gene Ha on 5DS. RFLP markers previously obtained for powdery-mildew (Blumeria graminis f.sp. tritici) resistance genes Pm2 and Pm1 were localized on chromosome arms 5DS and 7AL.
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Zwick, Michael S., M. Nurul Islam-Faridi, Don G. Czeschin, et al. "Physical Mapping of the liguleless Linkage Group in Sorghum bicolor Using Rice RFLP-Selected Sorghum BACs." Genetics 148, no. 4 (1998): 1983–92. http://dx.doi.org/10.1093/genetics/148.4.1983.
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Abstract Physical mapping of BACs by fluorescent in situ hybridization (FISH) was used to analyze the liguleless (lg-1) linkage group in sorghum and compare it to the conserved region in rice and maize. Six liguleless-associated rice restriction fragment length polymorphism (RFLP) markers were used to select 16 homeologous sorghum BACs, which were in turn used to physically map the liguleless linkage group in sorghum. Results show a basic conservation of the liguleless region in sorghum relative to the linkage map of rice. One marker which is distal in rice is more medial in sorghum, and another marker which is found within the linkage group in rice is on a different chromosome in sorghum. BACs associated with linkage group I hybridize to chromosome It, which was identified by using FISH in a sorghum cytogenetic stock trisomic for chromosome I (denoted It), and a BAC associated with linkage group E hybridized to an unidentified chromosome. Selected BACs, representing RFLP loci, were end-cloned for RFLP mapping, and the relative linkage order of these clones was in full agreement with the physical data. Similarities in locus order and the association of RFLP-selected BAC markers with two different chromosomes were found to exist between the linkage map of the liguleless region in maize and the physical map of the liguleless region in sorghum.
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Farman, M. L., and S. A. Leong. "Genetic and physical mapping of telomeres in the rice blast fungus, Magnaporthe grisea." Genetics 140, no. 2 (1995): 479–92. http://dx.doi.org/10.1093/genetics/140.2.479.
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Abstract Telomeric restriction fragments were genetically mapped to a previously described linkage map of Magnaporthe grisea, using RFLPs identified by a synthetic probe. (TTAGGG)3. Frequent rearrangement of telomeric sequences was observed in progeny isolates creating a potential for misinterpretation of data. Therefore a consensus segregation data set used to minimize mapping errors. TWelve of the 14 telomeres were found to be genetically linked to existing RFLP markers. Second-dimensional electrophoresis of restricted chromosomes confirmed these linkage assignments and revealed the chromosomal location of the two unlinked telomeres. We were thus able to assign all 14 M. grisea telomeres to their respective chromosome ends. The Achilles' cleavage (AC) technique was employed to determine that chromosome 1 markers 11 and CH5-120H were approximately 1.8 Mb and 1.28 Mb, respectively, from their nearest telomeres. RecA-AC was also used to determine that unlinked telomere 6 was approximately 530 kb from marker CH5-176H in strain 2539 and 580 kb in Guy11. These experiments indicated that large portions of some chromosome ends are unrepresented by genetic markers and provided estimates of the relationship of genetic to physical distance in these regions of the genome.
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Meuwissen, Theo H. E., Astrid Karlsen, Sigbjørn Lien, Ingrid Olsaker, and Mike E. Goddard. "Fine Mapping of a Quantitative Trait Locus for Twinning Rate Using Combined Linkage and Linkage Disequilibrium Mapping." Genetics 161, no. 1 (2002): 373–79. http://dx.doi.org/10.1093/genetics/161.1.373.
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Abstract A novel and robust method for the fine-scale mapping of genes affecting complex traits, which combines linkage and linkage-disequilibrium information, is proposed. Linkage information refers to recombinations within the marker-genotyped generations and linkage disequilibrium to historical recombinations before genotyping started. The identity-by-descent (IBD) probabilities at the quantitative trait locus (QTL) between first generation haplotypes were obtained from the similarity of the marker alleles surrounding the QTL, whereas IBD probabilities at the QTL between later generation haplotypes were obtained by using the markers to trace the inheritance of the QTL. The variance explained by the QTL is estimated by residual maximum likelihood using the correlation structure defined by the IBD probabilities. Unlinked background genes were accounted for by fitting a polygenic variance component. The method was used to fine map a QTL for twinning rate in cattle, previously mapped on chromosome 5 by linkage analysis. The data consisted of large half-sib families, but the method could also handle more complex pedigrees. The likelihood of the putative QTL was very small along most of the chromosome, except for a sharp likelihood peak in the ninth marker bracket, which positioned the QTL within a region <1 cM in the middle part of bovine chromosome 5. The method was expected to be robust against multiple genes affecting the trait, multiple mutations at the QTL, and relatively low marker density.
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Cheng, Zhukuan, Gernot G. Presting, C. Robin Buell, Rod A. Wing, and Jiming Jiang. "High-Resolution Pachytene Chromosome Mapping of Bacterial Artificial Chromosomes Anchored by Genetic Markers Reveals the Centromere Location and the Distribution of Genetic Recombination Along Chromosome 10 of Rice." Genetics 157, no. 4 (2001): 1749–57. http://dx.doi.org/10.1093/genetics/157.4.1749.
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AbstractLarge-scale physical mapping has been a major challenge for plant geneticists due to the lack of techniques that are widely affordable and can be applied to different species. Here we present a physical map of rice chromosome 10 developed by fluorescence in situ hybridization (FISH) mapping of bacterial artificial chromosome (BAC) clones on meiotic pachytene chromosomes. This physical map is fully integrated with a genetic linkage map of rice chromosome 10 because each BAC clone is anchored by a genetically mapped restriction fragment length polymorphism marker. The pachytene chromosome-based FISH mapping shows a superior resolving power compared to the somatic metaphase chromosome-based methods. The telomere-centromere orientation of DNA clones separated by 40 kb can be resolved on early pachytene chromosomes. Genetic recombination is generally evenly distributed along rice chromosome 10. However, the highly heterochromatic short arm shows a lower recombination frequency than the largely euchromatic long arm. Suppression of recombination was found in the centromeric region, but the affected region is far smaller than those reported in wheat and barley. Our FISH mapping effort also revealed the precise genetic position of the centromere on chromosome 10.
7
Tanksley, S. D., M. W. Ganal, J. P. Prince, et al. "High density molecular linkage maps of the tomato and potato genomes." Genetics 132, no. 4 (1992): 1141–60. http://dx.doi.org/10.1093/genetics/132.4.1141.
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Abstract High density molecular linkage maps, comprised of more than 1000 markers with an average spacing between markers of approximately 1.2 cM (ca. 900 kb), have been constructed for the tomato and potato genomes. As the two maps are based on a common set of probes, it was possible to determine, with a high degree of precision, the breakpoints corresponding to 5 chromosomal inversions that differentiate the tomato and potato genomes. All of the inversions appear to have resulted from single breakpoints at or near the centromeres of the affected chromosomes, the result being the inversion of entire chromosome arms. While the crossing over rate among chromosomes appears to be uniformly distributed with respect to chromosome size, there is tremendous heterogeneity of crossing over within chromosomes. Regions of the map corresponding to centromeres and centromeric heterochromatin, and in some instances telomeres, experience up to 10-fold less recombination than other areas of the genome. Overall, 28% of the mapped loci reside in areas of putatively suppressed recombination. This includes loci corresponding to both random, single copy genomic clones and transcribed genes (detected with cDNA probes). The extreme heterogeneity of crossing over within chromosomes has both practical and evolutionary implications. Currently tomato and potato are among the most thoroughly mapped eukaryotic species and the availability of high density molecular linkage maps should facilitate chromosome walking, quantitative trait mapping, marker-assisted breeding and evolutionary studies in these two important and well studied crop species.
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Hanic-Joyce, Pamela J. "MAPPING CDC MUTATIONS IN THE YEAST S. Cerevisiae BY RAD52-MEDIATED CHROMOSOME LOSS." Genetics 110, no. 4 (1985): 591–607. http://dx.doi.org/10.1093/genetics/110.4.591.
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ABSTRACT Using the chromosome loss-mapping method of Schild and Mortimer, I have mapped several new temperature-sensitive mutations that define five CDC genes. Modified procedures were used to facilitate mapping temperature-sensitive mutations in general, and these modifications are discussed. The mutations were assigned to specific chromosomes by chromosome loss procedures, and linkage relationships were determined subsequently by standard tetrad analysis. Four of the mutations define new loci. The fifth mutation, cdc63-1, is shown to be allelic to previously known mutations in the PRT1 gene.
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Sibley, L. D., A. J. LeBlanc, E. R. Pfefferkorn, and J. C. Boothroyd. "Generation of a restriction fragment length polymorphism linkage map for Toxoplasma gondii." Genetics 132, no. 4 (1992): 1003–15. http://dx.doi.org/10.1093/genetics/132.4.1003.
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Abstract We have constructed a genetic linkage map for the parasitic protozoan, Toxoplasma gondii, using randomly selected low copy number DNA markers that define restriction fragment length polymorphisms (RFLPs). The inheritance patterns of 64 RFLP markers and two phenotypic markers were analyzed among 19 recombinant haploid progeny selected from two parallel genetic crosses between PLK and CEP strains. In these first successful interstrain crosses, these RFLP markers segregated into 11 distinct genetic linkage groups that showed close correlation with physical linkage groups previously defined by molecular karyotype. Separate linkage maps, constructed for each of the 11 chromosomes, indicated recombination frequencies range from approximately 100 to 300 kb per centimorgan. Preliminary linkage assignments were made for the loci regulating sinefungin resistance (snf-1) on chromosome IX and adenine arabinoside (ara-1) on chromosome V by linkage to RFLP markers. Despite random segregation of separate chromosomes, the majority of chromosomes failed to demonstrate internal recombination events and in 3/19 recombinant progeny no intramolecular recombination events were detected. The relatively low rate of intrachromosomal recombination predicts that tight linkage for unknown genes can be established with a relatively small set of markers. This genetic linkage map should prove useful in mapping genes that regulate drug resistance and other biological phenotypes in this important opportunistic pathogen.
10
Grivet, Laurent, Angelique D'Hont, Daniele Roques, Philippe Feldmann, Claire Lanaud, and Jean Christophe Glaszmann. "RFLP Mapping in Cultivated Sugarcane (Saccharum spp.): Genome Organization in a Highly Polyploid and Aneuploid Interspecific Hybrid." Genetics 142, no. 3 (1996): 987–1000. http://dx.doi.org/10.1093/genetics/142.3.987.
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Abstract Sugarcane cultivars are polyploid, aneuploid, interspecific hybrids between the domesticated species Saccharum officinarum and the wild relative S. spontaneum. Cultivar chromosome numbers range from 100 to 130 with ~10% contributed by S. spontaneum. We have undertaken a mapping study on the progeny of a selfed cultivar, R570, to analyze this complex genome structure. A set of 128 restriction fragment length polymorphism probes and one isozyme was used. Four hundred and eight markers were placed onto 96 cosegregation groups, based on linkages in coupling only. These groups could tentatively be assembled into 10 basic linkage groups on the basis of common probes. Origin of markers was investigated for 61 probes and the isozyme, leading to the identification of 80 S. officinarum and 66 S. spontaneum derived markers, respectively. Their distribution in cosegregation groups showed better map coverage for the S. spontaneum than for the S. officinnrum genome fraction and occasional recombination between the two genomes. The study of repulsions between markers suggested the prevalence of random pairing between chromosomes, typical of autopolyploids. However, cases of preferential pairing between S. spontaneum chromosomes were also detected. A tentative Saccharum map was constructed by pooling linkage information for each linkage group.
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Krylov, Vladimir, and Tereza Tlapakova. "Xenopus Cytogenetics and Chromosomal Evolution." Cytogenetic and Genome Research 145, no. 3-4 (2015): 192–200. http://dx.doi.org/10.1159/000406550.
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The genus Xenopus represents important model organisms in the field of developmental biology and chromosomal evolution. Developmental processes are tightly coupled with the analysis of gene function via genetic linkage and mapping. Cytogenetic techniques such as chromosome banding or FISH are essential tools for the determination of gene position and subsequently for the construction of linkage and physical maps. Here, we present a summary of key achievements in X. tropicalis and X. laevis cytogenetics with emphasis on the gene localization to chromosomes. The second part of this review is focused on the chromosomal evolution regarding both above-mentioned species. With respect to methodology, hybridization techniques such as FISH and chromosome-specific painting FISH are highlighted.
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Dunford, Roy P., Masahiro Yano, Nori Kurata, et al. "Comparative Mapping of the Barley Ppd-H1 Photoperiod Response Gene Region, Which Lies Close to a Junction Between Two Rice Linkage Segments." Genetics 161, no. 2 (2002): 825–34. http://dx.doi.org/10.1093/genetics/161.2.825.
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Abstract Comparative mapping of cereals has shown that chromosomes of barley, wheat, and maize can be described in terms of rice “linkage segments.” However, little is known about marker order in the junctions between linkage blocks or whether this will impair comparative analysis of major genes that lie in such regions. We used genetic and physical mapping to investigate the relationship between the distal part of rice chromosome 7L, which contains the Hd2 heading date gene, and the region of barley chromosome 2HS containing the Ppd-H1 photoperiod response gene, which lies near the junction between rice 7 and rice 4 linkage segments. RFLP markers were mapped in maize to identify regions that might contain Hd2 or Ppd-H1 orthologs. Rice provided useful markers for the Ppd-H1 region but comparative mapping was complicated by loss of colinearity and sequence duplications that predated the divergence of rice, maize, and barley. The sequences of cDNA markers were used to search for homologs in the Arabidopsis genome. Homologous sequences were found for 13 out of 16 markers but they were dispersed in Arabidopsis and did not identify any candidate equivalent region. The implications of the results for comparative trait mapping in junction regions are discussed.
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De Sanctis, G. T., J. B. Singer, A. Jiao, et al. "Quantitative trait locus mapping of airway responsiveness to chromosomes 6 and 7 in inbred mice." American Journal of Physiology-Lung Cellular and Molecular Physiology 277, no. 6 (1999): L1118—L1123. http://dx.doi.org/10.1152/ajplung.1999.277.6.l1118.
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Quantitative trait locus (QTL) mapping was used to identify chromosomal regions contributing to airway hyperresponsiveness in mice. Airway responsiveness to methacholine was measured in A/J and C3H/HeJ parental strains as well as in progeny derived from crosses between these strains. QTL mapping of backcross [(A/J × C3H/HeJ) × C3H/HeJ] progeny ( n = 137–227 informative mice for markers tested) revealed two significant linkages to loci on chromosomes 6 and 7. The QTL on chromosome 6 confirms the previous report by others of a linkage in this region in the same genetic backgrounds; the second QTL, on chromosome 7, represents a novel locus. In addition, we obtained suggestive evidence for linkage (logarithm of odds ratio = 1.7) on chromosome 17, which lies in the same region previously identified in a cross between A/J and C57BL/6J mice. Airway responsiveness in a cross between A/J and C3H/HeJ mice is under the control of at least two major genetic loci, with evidence for a third locus that has been previously implicated in an A/J and C57BL/6J cross; this indicates that multiple genetic factors control the expression of this phenotype.
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Yang, Yang, Benjamin D. Speth, Napatsakorn Boonyoo, et al. "Molecular mapping of three male-sterile, female-fertile mutants and generation of a comprehensive map of all known male sterility genes in soybean." Genome 57, no. 3 (2014): 155–60. http://dx.doi.org/10.1139/gen-2014-0018.
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In soybean, an environmentally stable male sterility system is vital for making hybrid seed production commercially viable. Eleven male-sterile, female-fertile mutants (ms1, ms2, ms3, ms4, ms5, ms6, ms7, ms8, ms9, msMOS, and msp) have been identified in soybean. Of these, eight (ms2, ms3, ms5, ms7, ms8, ms9, msMOS, and msp) have been mapped to soybean chromosomes. The objectives of this study were to (i) locate the ms1, ms4, and ms6 genes to soybean chromosomes; (ii) generate genetic linkage maps of the regions containing these genes; and (iii) develop a comprehensive map of all known male-sterile, female-fertile genes in soybean. The bulked segregant analysis technique was used to locate genes to soybean chromosomes. Microsatellite markers from the corresponding chromosomes were used on F2 populations to generate genetic linkage maps. The ms1 and ms6 genes were located on chromosome 13 (molecular linkage group F) and ms4 was present on chromosome 2 (molecular linkage group D1b). Molecular analyses revealed markers Satt516, BARCSOYSSR_02_1539, and AW186493 were located closest to ms1, ms4, and ms6, respectively. The ms1 and ms6 genes, although present on the same chromosome, were independently assorting with a genetic distance of 73.7 cM. Using information from this study and compiled information from previously published male sterility genes in soybean, a comprehensive genetic linkage map was generated. Eleven male sterility genes were present on seven soybean chromosomes. Four genes were present in two regions on chromosome 2 (molecular linkage group D1b) and two genes were present on chromosome 13 (molecular linkage group F).
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Kianian, Shahryar F., Bai-Chai Wu, Stephen L. Fox, Howard W. Rines, and Ronald L. Phillips. "Aneuploid marker assignment in hexaploid oat with the C genome as a reference for determining remnant homoeology." Genome 40, no. 3 (1997): 386–96. http://dx.doi.org/10.1139/g97-052.
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Nullisomic lines of hexaploid oat Avena sativa L. (2n = 6x − 2 = 40, AACCDD) cultivar Sun II were used to assign 134 DNA sequences to 10 chromosome-associated syntenic groups. A limited set of ditelosomic lines allowed localization of subsets of these sequences to six chromosome arms. Advantages of using such aneuploids in mapping are in the assignment of gene families, monomorphic RFLP sequences, and oat linkage groups to chromosomes. The published hexaploid oat RFLP linkage map has 38 linkage groups, 17 more than expected on the basis of the haploid chromosome number. Using nullisomics, eight linkage groups were assigned to five physical chromosomes; using ditelosomics, three of these linkage groups were assigned to their respective chromosome arms. The A- and D-genome chromosome sets of oat are indistinguishable from each other based on different staining and genomic in situ hybridization techniques, while C-genome chromosomes are distinct. Because chromosomal rearrangements such as translocations and inversions have played an important role in the evolution of hexaploid oat, the distinction of C-genome chromosomes can be used to determine remnant homoeologous segments that exist in the other two genomes. Among the 10 syntenic groups identified, six chromosomes showed sequence homoeology believed to represent segmental homoeologous regions. Owing to various evolutionary forces, segmental homoeology instead of whole chromosome homoeology appears to best describe the genome organization in hexaploid oat.Key words: oat, aneuploids, syntenic associations, homoeology, C genome.
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Islam-Faridi, M. N., K. L. Childs, P. E. Klein, et al. "A Molecular Cytogenetic Map of Sorghum Chromosome1: Fluorescencein SituHybridization Analysis With Mapped Bacterial Artificial Chromosomes." Genetics 161, no. 1 (2002): 345–53. http://dx.doi.org/10.1093/genetics/161.1.345.
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AbstractWe used structural genomic resources for Sorghum bicolor (L.) Moench to target and develop multiple molecular cytogenetic probes that would provide extensive coverage for a specific chromosome of sorghum. Bacterial artificial chromosome (BAC) clones containing molecular markers mapped across sorghum linkage group A were labeled as probes for fluorescence in situ hybridization (FISH). Signals from single-, dual-, and multiprobe BAC-FISH to spreads of mitotic chromosomes and pachytene bivalents were associated with the largest sorghum chromosome, which bears the nucleolus organizing region (NOR). The order of individual BAC-FISH loci along the chromosome was fully concordant to that of marker loci along the linkage map. In addition, the order of several tightly linked molecular markers was clarified by FISH analysis. The FISH results indicate that markers from the linkage map positions 0.0-81.8 cM reside in the short arm of chromosome 1 whereas markers from 81.8-242.9 cM are located in the long arm of chromosome 1. The centromere and NOR were located in a large heterochromatic region that spans ∼60% of chromosome 1. In contrast, this region represents only 0.7% of the total genetic map distance of this chromosome. Variation in recombination frequency among euchromatic chromosomal regions also was apparent. The integrated data underscore the value of cytological data, because minor errors and uncertainties in linkage maps can involve huge physical regions. The successful development of multiprobe FISH cocktails suggests that it is feasible to develop chromosome-specific “paints” from genomic resources rather than flow sorting or microdissection and that when applied to pachytene chromatin, such cocktails provide an especially powerful framework for mapping. Such a molecular cytogenetic infrastructure would be inherently cross-linked with other genomic tools and thereby establish a cytogenomics system with extensive utility in development and application of genomic resources, cloning, transgene localization, development of plant “chromonomics,” germplasm introgression, and marker-assisted breeding. In combination with previously reported work, the results indicate that a sorghum cytogenomics system would be partially applicable to other gramineous genera.
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Veltsos, Paris, Kate E. Ridout, Melissa A. Toups, et al. "Early Sex-Chromosome Evolution in the Diploid Dioecious Plant Mercurialis annua." Genetics 212, no. 3 (2019): 815–35. http://dx.doi.org/10.1534/genetics.119.302045.
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Suppressed recombination allows divergence between homologous sex chromosomes and the functionality of their genes. Here, we reveal patterns of the earliest stages of sex-chromosome evolution in the diploid dioecious herb Mercurialis annua on the basis of cytological analysis, de novo genome assembly and annotation, genetic mapping, exome resequencing of natural populations, and transcriptome analysis. The genome assembly contained 34,105 expressed genes, of which 10,076 were assigned to linkage groups. Genetic mapping and exome resequencing of individuals across the species range both identified the largest linkage group, LG1, as the sex chromosome. Although the sex chromosomes of M. annua are karyotypically homomorphic, we estimate that about one-third of the Y chromosome, containing 568 transcripts and spanning 22.3 cM in the corresponding female map, has ceased recombining. Nevertheless, we found limited evidence for Y-chromosome degeneration in terms of gene loss and pseudogenization, and most X- and Y-linked genes appear to have diverged in the period subsequent to speciation between M. annua and its sister species M. huetii, which shares the same sex-determining region. Taken together, our results suggest that the M. annua Y chromosome has at least two evolutionary strata: a small old stratum shared with M. huetii, and a more recent larger stratum that is probably unique to M. annua and that stopped recombining ∼1 MYA. Patterns of gene expression within the nonrecombining region are consistent with the idea that sexually antagonistic selection may have played a role in favoring suppressed recombination.
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Gadaleta, A., A. Giancaspro, S. L. Giove, et al. "Development of a deletion and genetic linkage map for the 5A and 5B chromosomes of wheat (Triticum aestivum)." Genome 55, no. 6 (2012): 417–27. http://dx.doi.org/10.1139/g2012-028.
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The aims of the present study were to provide deletion maps for wheat ( Triticum aestivum L.) chromosomes 5A and 5B and a detailed genetic map of chromosome 5A enriched with popular microsatellite markers, which could be compared with other existing maps and useful for mapping major genes and quantitative traits loci (QTL). Physical mapping of 165 gSSR and EST–SSR markers was conducted by amplifying each primer pair on Chinese Spring, aneuploid lines, and deletion lines for the homoeologous group 5 chromosomes. A recombinant inbred line (RIL) mapping population that is recombinant for only chromosome 5A was obtained by crossing the wheat cultivar Chinese Spring and the disomic substitution line Chinese Spring-5A dicoccoides and was used to develop a genetic linkage map of chromosome 5A. A total of 67 markers were found polymorphic between the parental lines and were mapped in the RIL population. Sixty-three loci and the Q gene were clustered in three linkage groups ordered at a minimum LOD score of 5, while four loci remained unlinked. The whole genetic 5A chromosome map covered 420.2 cM, distributed among three linkage groups of 189.3, 35.4, and 195.5 cM. The EST sequences located on chromosomes 5A and 5B were used for comparative analysis against Brachypodium distachyon (L.) P. Beauv. and rice ( Oryza sativa L.) genomes to resolve orthologous relationships among the genomes of wheat and the two model species.
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Brubaker, Curt L., and Anthony H. D. Brown. "The use of multiple alien chromosome addition aneuploids facilitates genetic linkage mapping of the Gossypium G genome." Genome 46, no. 5 (2003): 774–91. http://dx.doi.org/10.1139/g03-063.
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Primary germplasm pools represent the most accessible source of new alleles for crop improvement, but not all effective alleles are available in the primary germplasm pool, and breeders must sometimes confront the difficulties of introgressing genes from the secondary and tertiary germplasm pools in cotton by using synthetic polyploids as introgression bridges. Two parental Gossypium nelsonii × Gossypium australe AFLP genetic linkage maps were used to identify G genome chromosome-specific molecular markers, which in turn were used to track the fidelity and frequency of G. australe chromosome transmission in a Gossypium hirsutum × G. australe hexaploid bridging family. Conversely, when homoeologous recombination is low, first generation aneuploids are useful adjuncts to genetic linkage mapping. Although locus ordering was not possible, the distribution of AFLP markers among 18 multiple chromosome addition aneuploids identified mapping errors among the G. australe and G. nelsonii linkage groups and assigned non-segregating G. australe AFLPs to linkage groups. Four putatively recombined G. australe chromosomes were identified in 5 of the 18 aneuploids. The G. australe and G. nelsonii genetic linkage maps presented here represent the first AFLP genetic linkage maps for the Gossypium G genome.Key words: Gossypium, G genome, AFLP, cotton, aneuploid.
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Naruse, Kiyoshi, Shoji Fukamachi, Hiroshi Mitani, et al. "A Detailed Linkage Map of Medaka, Oryzias latipes: Comparative Genomics and Genome Evolution." Genetics 154, no. 4 (2000): 1773–84. http://dx.doi.org/10.1093/genetics/154.4.1773.
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Abstract We mapped 633 markers (488 AFLPs, 28 RAPDs, 34 IRSs, 75 ESTs, 4 STSs, and 4 phenotypic markers) for the Medaka Oryzias latipes, a teleost fish of the order Beloniformes. Linkage was determined using a reference typing DNA panel from 39 cell lines derived from backcross progeny. This panel provided unlimited DNA for the accumulation of mapping data. The total map length of Medaka was 1354.5 cM and 24 linkage groups were detected, corresponding to the haploid chromosome number of the organism. Thirteen to 49 markers for each linkage group were obtained. Conserved synteny between Medaka and zebrafish was observed for 2 independent linkage groups. Unlike zebrafish, however, the Medaka linkage map showed obvious restriction of recombination on the linkage group containing the male-determining region (Y) locus compared to the autosomal chromosomes.
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Kurtz, T. W., and E. M. St Lezin. "Gene mapping in experimental hypertension." Journal of the American Society of Nephrology 3, no. 1 (1992): 28–34. http://dx.doi.org/10.1681/asn.v3128.
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In the rat, the results of genetic linkage studies by "candidate" gene or "positional mapping" approaches have suggested that DNA sequences that regulate blood pressure may be located in the vicinity of the kallikrein gene family on chromosome 1, the gene for angiotensin-converting enzyme on chromosome 10, the renin gene on chromosome 13, and the major histocompatibility complex on chromosome 20. Some studies have also suggested that blood pressure regulatory genes may be located on the sex chromosomes. Pending the results of confirmatory studies, these experiments should be interpreted with caution. However, with confirmation of these studies, it should be possible to create a variety of new animal models that will provide excellent opportunities for investigating the molecular, biochemical, and physiologic determinants of high blood pressure. In addition, in genetic studies in humans with essential hypertension, it may be worthwhile to target chromosome regions that are homologous to those implicated in linkage studies of hypertension in rodents. By narrowing the focus on selected areas of the genome, experimental linkage studies in the rat may also be used to guide the detailed molecular approaches ultimately required to identify the specific DNA sequence alterations that give rise to increased blood pressure.
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Stephens, J. L., S. E. Brown, N. L. V. Lapitan, and D. L. Knudson. "Physical mapping of barley genes using an ultrasensitive fluorescence in situ hybridization technique." Genome 47, no. 1 (2004): 179–89. http://dx.doi.org/10.1139/g03-084.
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The primary objective of this study was to elucidate gene organization and to integrate the genetic linkage map for barley (Hordeum vulgare L.) with a physical map using ultrasensitive fluorescence in situ hybridization (FISH) techniques for detecting signals from restriction fragment length polymorphism (RFLP) clones. In the process, a single landmark plasmid, p18S5Shor, was constructed that identified and oriented all seven of the chromosome pairs. Plasmid p18S5Shor was used in all hybridizations. Fourteen cDNA probes selected from the linkage map for barley H. vulgare 'Steptoe' × H. vulgare 'Morex' (Kleinhofs et al. 1993) were mapped using an indirect tyramide signal amplification technique and assigned to a physical location on one or more chromosomes. The haploid barley genome is large and a complete physical map of the genome is not yet available; however, it was possible to integrate the linkage map and the physical locations of these cDNAs. An estimate of the ratio of base pairs to centimorgans was an average of 1.5 Mb/cM in the distal portions of the chromosome arms and 89 Mb/cM near the centromere. Furthermore, while it appears that the current linkage maps are well covered with markers along the length of each arm, the physical map showed that there are large areas of the genome that have yet to be mapped.Key words: Hordeum vulgare, barley, physical mapping, FISH, cDNA, genetics, linkage, chromosome, BACs.
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Mautino, M. R., S. D. Haedo, and A. L. Rosa. "Physical mapping of meiotic crossover events in a 200-kb region of Neurospora crassa linkage group I." Genetics 134, no. 4 (1993): 1077–83. http://dx.doi.org/10.1093/genetics/134.4.1077.
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Abstract We propose a general restriction fragment length polymorphism-based strategy to analyze the distribution of meiotic crossover events throughout specific genetic intervals. We have isolated 64 recombinant chromosomes carrying independent meiotic crossover events in the genetic interval eth-1-un-2 on linkage group I of Neurospora crassa. Thirty-eight crossover events were physically mapped with reference to a 200-kb region cloned by chromosome walking, using N. crassa lambda and cosmid libraries. Crossovers were homogeneously distributed at intervals of 5.0 +/- 2.3 kb along the entire cloned interval. The ratio of physical to genetic distance appears to be higher in the region than in the overall N. crassa genome, suggesting that recombinational activity is less in large chromosomes than in small ones. The present work provides a method for defining the centromeric-telomeric orientation of single cloned DNA fragments. Their physical distance can also be estimated with respect to linked loci, provided that crossover events are distributed homogeneously in the interval. This strategy overcomes typical difficulties in defining the position and direction of chromosome walking steps on conventional linkage maps.
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Justice, M. J., L. D. Siracusa, D. J. Gilbert, et al. "A genetic linkage map of mouse chromosome 10: localization of eighteen molecular markers using a single interspecific backcross." Genetics 125, no. 4 (1990): 855–66. http://dx.doi.org/10.1093/genetics/125.4.855.
Full textAbstract:
Abstract Interspecific mouse backcross analysis was used to generate a molecular genetic linkage map of mouse chromosome 10. The map locations of the Act-2, Ahi-1, Bcr, Braf, Cdc-2a, Col6a-1, Col6a-2, Cos-1, Esr, Fyn, Gli, Ifg, Igf-1, Myb, Pah, pgcha, Ros-1 and S100b loci were determined. These loci extend over 80% of the genetic length of the chromosome, providing molecular access to many regions of chromosome 10 for the first time. The locations of the genes mapped in this study extend the known regions of synteny between mouse chromosome 10 and human chromosomes 6, 10, 12 and 21, and reveal a novel homology segment between mouse chromosome 10 and human chromosome 22. Several loci may lie close to, or correspond to, known mutations. Preferential transmission of Mus spretus-derived alleles was observed for loci mapping to the central region of mouse chromosome 10.
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Luo, Chao-Xi, Liang-Fen Yin, Satomi Koyanagi, Mark L. Farman, Motoaki Kusaba, and Hiroshi Yaegashi. "Genetic Mapping and Chromosomal Assignment of Magnaporthe oryzae Avirulence Genes AvrPik, AvrPiz, and AvrPiz-t Controlling Cultivar Specificity on Rice." Phytopathology® 95, no. 6 (2005): 640–47. http://dx.doi.org/10.1094/phyto-95-0640.
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A genetic map including three avirulence (Avr) genes, AvrPik, AvrPiz, and AvrPiz-t, was constructed in a genetic cross of two rice field isolates, 84R-62B and Y93-245c-2. The chromosomal locations of the Avr genes were determined by using selected markers to probe Southern blots of the parental chromosomes that had been separated by contour-clamped homogenous electric fields electrophoresis. Electrophoretic karyotyping showed that both parental isolates 84R-62B and Y93-245c-2 contained seven chromosomes greater than 3.5 megabases (Mb) in size and 84R-62B possessed a small chromosome of ≈1.6 Mb. The linkage groups containing AvrPiz and AvrPiz-t were assigned to chromosomes 3 and 7, respectively. Some markers from the linkage group that contained AvrPik hybridized with chromosome 1 and the 1.6-Mb chromosome, yet all of the cloned RAPD markers that were closely linked to AvrPik hybridized exclusively to the 1.6-Mb chromosome in 84R-62B, the parent that possesses AvrPik. Thus, we conclude that AvrPik is located on the 1.6-Mb chromosome in 84R-62B.
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Kam-Morgan, L. N. W., B. S. Gill, and S. Muthukrishnan. "DNA restriction fragment length polymorphisms: a strategy for genetic mapping of D genome of wheat." Genome 32, no. 4 (1989): 724–32. http://dx.doi.org/10.1139/g89-503.
Full textAbstract:
The use of restriction fragment length polymorphisms (RFLPs) as genetic markers in bread wheat, Triticum aestivum, and a wild wheat progenitor, Aegilops squarrosa, was investigated. The objectives were (i) to identify RFLP loci; (ii) to assign cDNA sequences onto specific chromosomes and chromosome arms; and (iii) to determine linkage relationships between RFLP loci. A low level of polymorphism was found, utilizing barley cDNA clones as probes, in hexaploid cultivated wheats. However, accessions of A. squarrosa revealed greater polymorphism. Wheat–barley alien addition lines were used to assign 17 cDNA sequences to specific chromosome groups and ditelosomic and nullisomic–tetrasomic wheat stocks were used to assign these sequences to specific chromosome arms. Of 16 sets of RFLP loci, excluding α-Amy-1 and α-Amy-2, 14 are new sets of loci marking 6 of the 7 homoeologous groups of wheat. The construction of a linkage map of chromosome 5D was initiated by analyzing a segregating F2 population between two homozygous accessions of A. squarrosa. A strategy using wheat aneuploids for chromosome arm location and a segregating A. squarrosa population for linkage measurement was demonstrated for mapping the D-genome chromosomes of wheat.Key words: genetic map, restriction fragment length polymorphisms, Triticum aestivum, Aegilops squarrosa, polyploidy.
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Aign, Verena, Ulrich Schulte, and Jörg D. Hoheisel. "Hybridization-Based Mapping ofNeurospora crassaLinkage Groups II and V." Genetics 157, no. 3 (2001): 1015–20. http://dx.doi.org/10.1093/genetics/157.3.1015.
Full textAbstract:
AbstractAs part of the German Neurospora crassa genome project, physical clone maps of linkage groups II and V of N. crassa were generated by hybridization-based mapping. To this end, two different types of clone library were used: (1) a bacterial artificial clone library of 15-fold genome coverage and an average insert size of 69 kb, and (2) three cosmid libraries—each cloned in a different vector—with 17-fold coverage and 34 kb average insert size. For analysis, the libraries were arrayed on filters. At the first stage, chromosome-specific sublibraries were selected by hybridization of the respective chromosomal DNA fragments isolated from pulsed-field electrophoresis gels. Subsequently, the sublibraries were exhaustively ordered by single clone hybridizations. Eventually, the global libraries were used again for gap filling. By this means, physical maps were generated that consist of 13 and 21 contigs, respectively, and form the basis of the current sequencing effort on the two chromosomes.
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Bosetti, A., A. Faiella, E. Boncinelli, and G. G. Consalez. "Linkage mapping of Emx2 to mouse Chromosome 19." Mammalian Genome 8, no. 1 (1997): 71–72. http://dx.doi.org/10.1007/s003359900356.
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Chen, Xiaowei, and Thomas Lufkin. "Linkage mapping of Sax2 to mouse Chromosome 5." Mammalian Genome 8, no. 9 (1997): 697–98. http://dx.doi.org/10.1007/s003359900541.
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DECKER, R., J. MOORE, B. PONDER, and J. WEBER. "Linkage mapping of human chromosome 10 microsatellite polymorphisms." Genomics 12, no. 3 (1992): 604–6. http://dx.doi.org/10.1016/0888-7543(92)90455-2.
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Sun, H. S., L. Cai, S. K. Davis, et al. "Comparative Linkage Mapping of Human Chromosome 13 and Bovine Chromosome 12." Genomics 39, no. 1 (1997): 47–54. http://dx.doi.org/10.1006/geno.1996.4481.
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Deng, Alan Y., William H. Smith-Mensah, Barbara Hoebee, Michael Garrett, and John P. Rapp. "Linkage mapping of rat chromosome markers generated from chromosome-sorted DNA." Mammalian Genome 9, no. 1 (1998): 38–43. http://dx.doi.org/10.1007/s003359900676.
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Huttley, Gavin A., Michael W. Smith, Mary Carrington, and Stephen J. O’Brien. "A Scan for Linkage Disequilibrium Across the Human Genome." Genetics 152, no. 4 (1999): 1711–22. http://dx.doi.org/10.1093/genetics/152.4.1711.
Full textAbstract:
Abstract Linkage disequilibrium (LD), the tendency for alleles of linked loci to co-occur nonrandomly on chromosomal haplotypes, is an increasingly useful phenomenon for (1) revealing historic perturbation of populations including founder effects, admixture, or incomplete selective sweeps; (2) estimating elapsed time since such events based on time-dependent decay of LD; and (3) disease and phenotype mapping, particularly for traits not amenable to traditional pedigree analysis. Because few descriptions of LD for most regions of the human genome exist, we searched the human genome for the amount and extent of LD among 5048 autosomal short tandem repeat polymorphism (STRP) loci ascertained as specific haplotypes in the European CEPH mapping families. Evidence is presented indicating that ∼4% of STRP loci separated by <4.0 cM are in LD. The fraction of locus pairs within these intervals that display small Fisher’s exact test (FET) probabilities is directly proportional to the inverse of recombination distance between them (1/cM). The distribution of LD is nonuniform on a chromosomal scale and in a marker density-independent fashion, with chromosomes 2, 15, and 18 being significantly different from the genome average. Furthermore, a stepwise (locus-by-locus) 5-cM sliding-window analysis across 22 autosomes revealed nine genomic regions (2.2-6.4 cM), where the frequency of small FET probabilities among loci was greater than or equal to that presented by the HLA on chromosome 6, a region known to have extensive LD. Although the spatial heterogeneity of LD we detect in Europeans is consistent with the operation of natural selection, absence of a formal test for such genomic scale data prevents eliminating neutral processes as the evolutionary origin of the LD.
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Zhi-Ben, Yi, Sun Yi, Liang Xiao-Hong, Zhao Wei-Jun, Yan Min, and Cui Li-Xia. "Advances in genetic mapping of the sorghum genome." Chinese Journal of Agricultural Biotechnology 3, no. 3 (2006): 155–61. http://dx.doi.org/10.1079/cjb2006111.
Full textAbstract:
AbstractThe construction of the sorghum (Sorghum bicolor L. Moench) molecular genetic linkage map started in the early 1990s. Molecular genetic maps with a high density of markers covering almost the entire sorghum genome have been completed and integration of a sorghum genetic and physical map is under way. The correlation between genetic linkage groups and relevant chromosomes was established and the locations of the important structures of chromosomes, such as centromeres, long and short arms, nucleolus organizer region (NOR), etc., have been identified on the linkage groups. Molecular cytogenetic mapping of each chromosome has been advanced substantially. With continuing progress in the field, sequencing of the full sorghum genome and study of sorghum functional genomics will be initiated soon.
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Parsons, Y. M., and K. L. Shaw. "Mapping Unexplored Genomes: A Genetic Linkage Map of the Hawaiian Cricket Laupala." Genetics 162, no. 3 (2002): 1275–82. http://dx.doi.org/10.1093/genetics/162.3.1275.
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Abstract As with many organisms of evolutionary interest, the Hawaiian cricket Laupala genome is not well characterized genetically. Mapping such an unexplored genome therefore presents challenges not often faced in model genetic organisms and not well covered in the literature. We discuss the evolutionary merits of Laupala as a model for speciation studies involving prezygotic change, our choice of marker system for detecting genetic variation, and the initial genetic expectations pertaining to the construction of any unknown genomic map in general and to the Laupala linkage map construction in particular. We used the technique of amplified fragment length polymorphism (AFLP) to develop a linkage map of Laupala. We utilized both EcoRI/MseI- and EcoRI/PstI-digested genomic DNA to generate AFLP bands and identified 309 markers that segregated among F2 interspecific hybrid individuals. The map is composed of 231 markers distributed over 11 and 7 species-specific autosomal groups together with a number of putative X chromosome linkage groups. The integration of codominant markers enabled the identification of five homologous linkage groups corresponding to five of the seven autosomal chromosomal pairs found in Laupala.
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Sahara, Ken, Atsuo Yoshido, František Marec, et al. "Conserved synteny of genes between chromosome 15 of Bombyx mori and a chromosome of Manduca sexta shown by five-color BAC-FISH." Genome 50, no. 11 (2007): 1061–65. http://dx.doi.org/10.1139/g07-082.
Full textAbstract:
The successful assignment of the existing genetic linkage groups (LGs) to individual chromosomes and the second-generation linkage map obtained by mapping a large number of bacterial artificial chromosome (BAC) contigs in the silkworm, Bombyx mori , together with public nucleotide sequence databases, offer a powerful tool for the study of synteny between karyotypes of B. mori and other lepidopteran species. Conserved synteny of genes between particular chromosomes can be identified by comparatively mapping orthologous genes of the corresponding linkage groups with the help of BAC-FISH (fluorescent in situ hybridization). This technique was established in B. mori for 2 differently labeled BAC probes simultaneously hybridized to pachytene bivalents. To achieve higher-throughput comparative mapping using BAC-FISH in Lepidoptera, we developed a protocol for five-color BAC-FISH, which allowed us to map simultaneously 6 different BAC probes to chromosome 15 in B. mori. We identified orthologs of 6 B. mori LG15 genes (RpP0, RpS8, eIF3, RpL7A, RpS23, and Hsc70) for the tobacco hornworm, Manduca sexta , and selected the ortholog-containing BAC clones from an M. sexta BAC library. All 6 M. sexta BAC clones hybridized to a single M. sexta bivalent in pachytene spermatocytes. Thus, we have confirmed the conserved synteny between the B. mori chromosome 15 and the corresponding M. sexta chromosome (hence provisionally termed chromosome 15).
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Green, P. "Genetic Analysis Workshop 7: Mapping chromosome 21 linkage markers." Cytogenetic and Genome Research 59, no. 2-3 (1992): 77–79. http://dx.doi.org/10.1159/000133204.
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Whitkus, R., J. Doebley, and M. Lee. "Comparative genome mapping of Sorghum and maize." Genetics 132, no. 4 (1992): 1119–30. http://dx.doi.org/10.1093/genetics/132.4.1119.
Full textAbstract:
Abstract Linkage relationships were determined among 85 maize low copy number nuclear DNA probes and seven isozyme loci in an F2 population derived from a cross of Sorghum bicolor ssp. bicolor x S. bicolor ssp. arundinaceum. Thirteen linkage groups were defined, three more than the 10 chromosomes of sorghum. Use of maize DNA probes to produce the sorghum linkage map allowed us to make several inferences concerning processes involved in the evolutionary divergence of the maize and sorghum genomes. The results show that many linkage groups are conserved between these two genomes and that the amount of recombination in these conserved linkage groups is roughly equivalent in maize and sorghum. Estimates of the proportions of duplicated loci suggest that a larger proportion of the loci are duplicated in the maize genome than in the sorghum genome. This result concurs with a prior estimate that the nuclear DNA content of maize is three to four times greater than that of sorghum. The pattern of conserved linkages between maize and sorghum is such that most sorghum linkage groups are composed of loci that map to two maize chromosomes. This pattern is consistent with the hypothesized ancient polyploid origin of maize and sorghum. There are nine cases in which locus order within shared linkage groups is inverted in sorghum relative to maize. These may have arisen from either inversions or intrachromosomal translocations. We found no evidence for large interchromosomal translocations. Overall, the data suggest that the primary processes involved in divergence of the maize and sorghum genomes were duplications (either by polyploidy or segmental duplication) and inversions or intrachromosomal translocations.
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Voss, S. Randal, Jeramiah J. Smith, David M. Gardiner, and David M. Parichy. "Conserved Vertebrate Chromosome Segments in the Large Salamander Genome." Genetics 158, no. 2 (2001): 735–46. http://dx.doi.org/10.1093/genetics/158.2.735.
Full textAbstract:
Abstract Urodele amphibians (salamanders) are important models for embryological, physiological, and natural history research and are also a biomedically important group because they are the only vertebrates capable of regenerating entire organ systems. To enhance the utility of salamanders for biomedical research and for understanding genome evolution, genetic linkage analysis was used to identify chromosome segments that are homologous between ambystomatid salamanders and distantly related vertebrate model organisms. A total of 347 loci (AFLPs, RAPDs, and protein-coding loci) were mapped using an interspecific meiotic mapping panel (Ambystoma mexicanum and A. tigrinum tigrinum; family Ambystomatidae). Genome size in Ambystoma was estimated to be 7291 cM, the largest linkage map estimate reported for any organism. However, the relatively large size of the salamander genome did not hinder efforts to map and identify conserved syntenies from a small sample of 24 protein-coding loci. Chromosomal segments that are conserved between fishes and mammals are also conserved in these salamanders. Thus, comparative gene mapping appears to be an efficient strategy for identifying orthologous loci between ambystomatid salamanders and genomically well-characterized vertebrate model organisms.
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Castiglioni, P., C. Pozzi, M. Heun, et al. "An AFLP-Based Procedure for the Efficient Mapping of Mutations and DNA Probes in Barley." Genetics 149, no. 4 (1998): 2039–56. http://dx.doi.org/10.1093/genetics/149.4.2039.
Full textAbstract:
Abstract A strategy based upon AFLP markers for high-efficiency mapping of morphological mutations and DNA probes to linkage groups in barley is presented. First, 511 AFLP markers were placed on the linkage map derived from the cross Proctor × Nudinka. Second, loci controlling phenotypic traits were assigned to linkage groups by AFLP analysis, using F2 populations consisting of 30–50 mutant plants derived from crosses of the type “mutant × Proctor” and “mutant × Nudinka.” To map DNA probes, 67 different wild-type barley lines were selected to generate F2 populations by crossing with Proctor and Nudinka. F2 plants that were polymorphic for a given RFLP fragment were classified into genotypic classes. Linkage of the RFLP polymorphism to 1 of the 511 AFLP loci was indicated by cosegregation. The use of the strategy is exemplified by the mapping of the mutation branched-5 to chromosome 2 and of the DNA probes Bkn2 and BM-7 to chromosomes 5 and 1, respectively. Map expansion and marker order in map regions with dense clustering of markers represented a particular problem. A discussion considering the effect of noncanonical recombinant products on these two parameters is provided.
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Kinoshita, K., T. Shimogiri, S. Okamoto, et al. "Linkage mapping of chickenovoinhibitorandovomucoidgenes to chromosome 13." Animal Genetics 35, no. 4 (2004): 356–58. http://dx.doi.org/10.1111/j.1365-2052.2004.01159.x.
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Kingsley, D. M., N. A. Jenkins, and N. G. Copeland. "A molecular genetic linkage map of mouse chromosome 9 with regional localizations for the Gsta, T3g, Ets-1 and Ldlr loci." Genetics 123, no. 1 (1989): 165–72. http://dx.doi.org/10.1093/genetics/123.1.165.
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Abstract A 64-centiMorgan linkage map of mouse chromosome 9 was developed using cloned DNA markers and an interspecific backcross between Mus spretus and the C57BL/6J inbred strain. This map was compared to conventional genetic maps using six markers previously localized in laboratory mouse strains. These markers included thymus cell antigen-1, cytochrome P450-3, dilute, transferrin, cholecystokinin, and the G-protein alpha inhibitory subunit. No evidence was seen for segregation distortion, chromosome rearrangements, or altered genetic distances in the results from interspecific backcross mapping. Regional map locations were determined for four genes that were previously assigned to chromosome 9 using somatic cell hybrids. These genes were glutathione S-transferase Ya subunit (Gsta), the T3 gamma subunit, the low density lipoprotein receptor, and the Ets-1 oncogene. The map locations for these genes establish new regions of synteny between mouse chromosome 9 and human chromosomes 6, 11, and 19. In addition, the close linkage detected between the dilute and Gsta loci suggests that the Gsta locus may be part of the dilute/short ear complex, one of the most extensively studied genetic regions of the mouse.
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Lan, Hong, Laurie A. Shepel, Jill D. Haag, and Michael N. Gould. "Linkage mapping of rat Chromosome 5 markers generated from chromosome-specific libraries." Mammalian Genome 10, no. 7 (1999): 687–91. http://dx.doi.org/10.1007/s003359901071.
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Crawford, A. M., G. W. Montgomery, C. A. Pierson, et al. "Sheep linkage mapping: nineteen linkage groups derived from the analysis of paternal half-sib families." Genetics 137, no. 2 (1994): 573–79. http://dx.doi.org/10.1093/genetics/137.2.573.
Full textAbstract:
Abstract Nineteen linkage groups containing a total of 52 markers have been identified in the sheep genome after typing large paternal half-sib families. The linkage groups range in size from 2 markers showing no recombination to a group containing 6 markers covering approximately 30 cM of the sheep genome. Thirteen of the groups have been assigned to a sheep chromosome. Three groups contain markers from bovine syntenic groups U2, U7 and U29, and one other group contains a marker that has been mapped only in humans. The remaining three groups are unassigned. This information will provide a useful foundation for a genetic linkage map of sheep.
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Lukaszewski, Adam J. "Genetic mapping in the 1R.1D wheat–rye translocated chromosomes." Genome 37, no. 6 (1994): 945–49. http://dx.doi.org/10.1139/g94-134.
Full textAbstract:
Translocation chromosomes 1R.1D5+10−1 and 1R.1D5+10−2 were produced to improve bread-making quality in triticale and to manipulate the dosage of the Glu-D1 gene in wheat. They involve transfers of segments of the long arm of chromosome 1D of bread wheat to the long arm of rye chromosome 1R. The translocated long arms of the chromosomes were mapped genetically in wheat and triticale using polymorphism for C-banding patterns, allelic variation of the Glu-D1 gene, and a telocentric chromosome 1RL. The total frequency and the general distribution of recombination in the translocated arms was similar to that in normal long arms of group-1 chromosomes in wheat, rye, and triticale, except that the distal rye segments of the translocations showed a 15- to 20-fold increase in recombination frequency compared with normal 1R. Despite major differences in the physical structure of the translocated arms, both appeared very similar genetically, suggesting that genetic mapping is a poor indicator of the physical structure of translocations. Genetic length of the 1DL segment in chromosome 1R.1D5+10−1 was 31 cM, making the chromosome unsuitable for Glu-D1 dosage manipulation in wheat. The potential of chromosome 1R.1D5+10−2 for wheat breeding needs further testing. However, both chromosomes behave normally in hexaploid triticale.Key words: translocation, linkage, bread-making quality, wheat, triticale.
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Deynze, A. E. Van, J. Dubcovsky, K. S. Gill, et al. "Molecular-genetic maps for group 1 chromosomes of Triticeae species and their relation to chromosomes in rice and oat." Genome 38, no. 1 (1995): 45–59. http://dx.doi.org/10.1139/g95-006.
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Group 1 chromosomes of the Triticeae tribe have been studied extensively because many important genes have been assigned to them. In this paper, chromosome 1 linkage maps of Triticum aestivum, T. tauschii, and T. monococcum are compared with existing barley and rye maps to develop a consensus map for Triticeae species and thus facilitate the mapping of agronomic genes in this tribe. The consensus map that was developed consists of 14 agronomically important genes, 17 DNA markers that were derived from known-function clones, and 76 DNA markers derived from anonymous clones. There are 12 inconsistencies in the order of markers among seven wheat, four barley, and two rye maps. A comparison of the Triticeae group 1 chromosome consensus map with linkage maps of homoeologous chromosomes in rice indicates that the linkage maps for the long arm and the proximal portion of the short arm of group 1 chromosomes are conserved among these species. Similarly, gene order is conserved between Triticeae chromosome 1 and its homoeologous chromosome in oat. The location of the centromere in rice and oat chromosomes is estimated from its position in homoeologous group 1 chromosomes of Triticeae.Key words: Triticeae, RFLP, consensus, comparative.
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Gelb, Bruce D., Jacob G. Edelson, and Robert J. Desnick. "Linkage of pycnodysostosis to chromosome 1q21 by homozygosity mapping." Nature Genetics 10, no. 2 (1995): 235–37. http://dx.doi.org/10.1038/ng0695-235.
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Yamada, S., H. Nakagama, M. Toyota, et al. "Linkage mapping of rat Rb1 gene on Chromosome 15." Mammalian Genome 8, no. 6 (1997): 454–55. http://dx.doi.org/10.1007/s003359900471.
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Alli, Cristina, and G. Giacomo Consalez. "Linkage mapping of Csrp to proximal mouse Chromosome 3." Mammalian Genome 9, no. 2 (1998): 172–73. http://dx.doi.org/10.1007/s003359900714.
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Siracusa, L. D., N. A. Jenkins, and N. G. Copeland. "Identification and applications of repetitive probes for gene mapping in the mouse." Genetics 127, no. 1 (1991): 169–79. http://dx.doi.org/10.1093/genetics/127.1.169.
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Abstract Interspecific mouse hybrids that are viable and fertile provide a wealth of genetic variation that is useful for gene mapping. We are using this genetic variation to develop multilocus linkage maps of the mouse genome. As an outgrowth of this work, we have identified three repetitive probes that collectively identify 28 loci dispersed on 16 of the 19 mouse autosomes and the X chromosome. These loci establish a skeleton linkage map that can be used to detect linkage over much of the mouse genome. The molecular probes are derived from the mouse mammary tumor virus envelope gene, the ornithine decarboxylase gene, and the triose phosphate isomerase gene. The ability to scan the mouse genome quickly and efficiently in an interspecific cross using these three repetitive probes makes this system a powerful tool for identifying the chromosomal location of mutations that have yet to be cloned, mapping multigenic traits, and identifying recessive protooncogene loci associated with murine neoplastic disease. Ultimately, interspecific hybrids in conjunction with repetitive and single-copy probes will provide a rapid means to access virtually any gene of interest in the mouse genome at the molecular level.