Dissertations / Theses on the topic 'Colobine'

Thesis (Ph.D.)--Kent State University, 2008.
Title from PDF t.p. (viewed May 21, 2009). Advisor: Marilyn A. Norconk. Keywords: theoretical evolutionary ecology, optimal foraging theory, diet, nutrition, ranging, cognition, colobine monkeys, Semnopithecus entellus. Includes bibliographical references (p. 166-193).

Nous tentons de decrire les caracteristiques socio-ecologiques de c. Satanas, d'etablir si elles sont specispecifiques ou soumises a des variations interpopulationnelles et comparons nos resultats (gabon, makande) avec ceux obtenus sur une population voisine du gabon et sur une du cameroun. La structure sociale est de type multimales. La cohesion des groupes est assuree par les relations sociales (epouillage) et par des comportements de contact. Reseaux de proximite spatiale et d'epouillage traduisent trois affinites : les males adultes interagissent entre eux, les immatures aussi, tandis que les femelles adultes interagissent entre elles et assurent le lien entre les classes d'age. Le role de ces femelles dans la cohesion du groupe et leur tolerance des comportements alloparentaux suggere une organisation matrilineaire. Mais les liens relationnels entre males adultes et le fait que males et femelles emigrent suggerent des caracteristiques patrilineaires. L'emigration en sous-groupes rend l'organisation sociale originale et rappelle la notion de communaute au sein de laquelle s'effectuent des fissions-fusions. C. Satanas est essentiellement granivore et l'exploitation du milieu varie selon les ressources et leur repartition. Domaines vitaux et deplacements sont plus importants a la makande ou l'exploitation semi-nomadique du milieu, les faibles densites de colobes et le faible taux de natalite pourraient resulter de la composition floristique de la foret. La dominance des caesalpiniaceae et les caracteristiques phenologiques de leur fructification accentuent la penurie des ressources en grande saison seche et provoquent des periodes critiques. De facon stochastique, ceci pourrait induire des chutes recurrentes de la population. Les caracteristiques socioecologiques et morpho-anatomiques de c. Satanas soulignent sa position clef dans la phylogenie des colobes africains, il pourrait etre la forme la plus proche de leur ancetre.

Nous décrivons un colobome papillaire isolé associé à une néphropathie évoluant vers l'insuffisance rénale terminale. Cette association est retrouvée chez trois membres d'une même famille sur trois générations successives. L'unique ponction biopsie pratiquée sur la fille du probant montre des lésions de type hyalinose segmentaire et focale ainsi qu'une sclérose interstitielle. L'hypothèse d'une troisième association, celle du syndrome de Parsonage et Turner reste en suspens. La revue de la littérature nous permet d'affirmer l'originalité de ce syndrome oculo-rénal. Cette association oculo-rénale ne serait pas fortuite. Son caractère hérédiataire orienterait vers un trouble constitutionnel.

L’ataxie spinocérébelleuse de type 7 (SCA7) est une maladie neurodégénérative à transmission autosomale dominante, causée par une expansion toxique de polyglutamine (polyQ) dans la protéine Ataxine-7. Elle se caractérise par une dégénérescence des photorécepteurs en cônes et en bâtonnets, ainsi que des cellules cérébelleuses de Purkinje et granuleuses. La nature sélective de cette dégénérescence reste peu claire, l’expression d’Ataxine-7 étant ubiquitaire. Dans ce contexte, nous avons exploré la fonction de l’orthologue d’Ataxine-7 chez le poisson-zèbre au cours du développement de l’œil. L’inactivation d’atxn7 chez le poisson-zèbre – par des approches utilisant des oligonucléotides anti-sens ou par CRISPR/Cas9 – résulte principalement en un colobome, malformation structurelle de l’œil causée par un défaut de fermeture de la fissure choroïde. Les morphants atxn7 présentent une altération du motif proximo-distal de la vésicule optique causée par une élévation de la signalisation Hedgehog (Hh). Une étude minutieuse des photorécepteurs révèle un défaut de la morphogénèse des segments externes. La sensibilité de l’œil aux variations de fonction d’atxn7 pourrait expliquer la phyiopathologie SCA7. Notre étude suggère également qu’une perte de fonction d’atxn7 contribuerait au développement du colobome chez l’Homme
Spinocerebellar ataxia type 7 (SCA7) is an autosomal-dominant neurodegenerative disorder caused by a toxic polyglutamine (polyQ) expansion in Ataxin-7 which leads to degeneration of cone and rod photoreceptors. The selective nature of degeneration remains unclear since Ataxin-7 is ubiquitously expressed. Here, we have explored the function of the Ataxin-7 ortholog in zebrafish during eye development. Inactivation of atxn7 in zebrafish primarily resulted in a coloboma defect, a structural malformation of the eye caused by failure of the choroid fissure to close. atxn7 morphants displayed altered proximo-distal patterning of the optic vesicle, caused by elevated Hedgehog (Hh) signaling. Careful examination of the photoreceptors reveals a defect in the morphogenesis of the outer segments. The eye sensitivity to variations in atxn7 function could account for SCA7 physiopathology. Our study also suggests that atxn7 loss of function may contribute to the development of human coloboma

This thesis details research into the ecology and behaviour of the black-shanked douc (Pygathrix nigripes Milne-Edwards, 1871), an Endangered colobine found in eastern Cambodia and southern Vietnam. The study was conducted in Seima Biodiversity Conservation Area (SBCA), Mondulkiri Province, Cambodia, over a period of 20 months, from January 2003 to August 2004, and therefore represents the longest-term study of any species in the genus. Distributional and relative density data show that black-shanked doucs preferentially utilise evergreen forest. There they maintain the largest group sizes and highest relative densities. The species is also commonly found in semi-evergreen and mixed deciduous forest, although the latter may be sub-optimal due to limited food resources. P. nigripes additionally occurs in dry deciduous dipterocarp forest but probably only where it is associated with one of the first three forest types. Group sizes appear to be lower in suboptimal habitats as suggested by the ecological constraints model. Four major social units occur in the species: one-male units (OMUs), bands comprised of several OMUs, bachelor groups and lone males. OMUs averaged 7.5 individuals, and were composed of a single male, several females and offspring. Black-shanked doucs have a fission-fusion social system, with fusion of OMUs into bands occurring more commonly in the wet season. The maximum band size recorded was 26 individuals. Activity budgets were similar to other colobine species. Inactivity dominated with a frequency of 61%, feeding 27%, travel 6%, social behaviour 3%, and other activities 2%. Daily distribution of activities was also a typically colobine pattern with high rates of feeding in the morning, a long midday period of inactivity followed by a second feeding bout in the afternoon. Locomotion was predominantly quadrupedal although frequencies of brachiation were significant. The majority of activities occurred in the middle to upper forest canopy: only one instance of terrestriality was recorded. Several behaviours not previously documented in wild doucs were observed, including paternalistic behaviour and allomothering. Contrary to previous studies on the feeding ecology of Pygathrix, P. nigripes at the site was best characterised as a seed predator, with 40% of feeding records being dedicated to seeds. Leaves, especially young leaves, also comprised a significant part of the diet.Doucs were highly selective in their diet, feeding from only 35 positively-identified plant species and with 44% of all feeding records coming from only five species. Legume species were heavily targeted. Diets did not track resource abundance across seasons with the exception of high levels of flower consumption correlated with high availability during the dry season and seed consumption during the wet season. SBCA holds the largest known population of the species across its range and is under active conservation management by the Wildlife Conservation Society and the Forestry Administration of the Royal Government of Cambodia and therefore represents one of the best opportunities for long-term conservation of the species. Having an understanding of habitat preferences, feeding ecology and behaviour as presented in this thesis provides a basis for management of the species at this site and beyond.
Grants from the Australian National University, Primate Conservation, Inc., Conservation International’s Primate Action Fund, American Society of Primatologists, Wildlife Conservation Society, Under the Counter Publishing and Hennessey Hammocks

Delacour’s langur (Trachypithecus delacouri) is a critically endangered Southeast Asian colobine, found in the karst outcrops of northern Vietnam. Half of the remaining population (estimated at fewer than 200 individuals) resides within Van Long Nature Reserve, Ninh Binh Province. This thesis aims to further the conservation of T. delacouri by reviewing the first release of captive-bred individuals as a potential conservation tool for the species, along with acquiring a greater understanding of the species’ behaviour. Behavioural focal observations were conducted throughout 2011, both on wild groups at Van Long and captive individuals at the Endangered Primate Rescue Center (EPRC) at Cuc Phuong National Park. A group of three individuals was released by the EPRC into Van Long in August 2011 in an aim to connect populations and promote interbreeding, and was tracked using GPS radio collars for a period of up to 13.5 months, with the release then evaluated in line with IUCN reintroduction guidelines. Activity budgets of the wild versus captive T. delacouri populations showed significant differences, although both were in line with typical colobine budgets. Inactivity dominated (wild 75.0%, captive 61.9%), with feeding behaviours also playing a major part (wild 21.3%, captive 29.0%). Sex differences were minimal, but age differences showed that young were more social, and adults spent more time inactive and less time feeding. Both affiliative and antagonistic social interactions were common, with females and young most likely to be involved in affiliative behaviours. Infants showed significant changes in their behaviour as they aged, becoming increasingly social and independent, with allomothering witnessed. Vocalisations were predominantly performed by adult males, with grunts the most common call (61.2%) of the seven identified. An individual’s sex/age class was significantly linked to the type of vocalisation performed. T. delacouri vocalisation behaviour was relatively similar to that of other limestone langurs, although some differences in call structure were found. The released individuals all survived for a minimum of five months before tracking was disrupted for one, showing some wild-like behaviours, although their behaviours were largely atypical. The group quickly separated to travel as individuals, and ranged extensively with the adult male covering 1020ha in 9.5 months. Average day journey lengths were comparable to other limestone langurs (453m–735m), but the individuals did not develop distinct home ranges. A strong diurnal trend in movement showed two peaks at early morning and late afternoon, but minimal seasonal differences were detected. More extensive monitoring is needed to determine whether or not the release was a success, but the project fulfilled an important role as a pilot study to learn how best to conduct a release and how the animals will behave. In reviewing the release it was found to have broadly followed the IUCN guidelines, although gaps were identified suggesting more formalised planning, risk assessments, and consultation was needed. Moving forward, the possibility of translocating existing T. delacouri subpopulations, rather than conducting further captive releases, should be explored as a conservation strategy, along with continuing the effective protection measures in place at Van Long.

Tese de mestrado, Biologia da Conservação, Universidade de Lisboa, Faculdade de Ciências, 2017
A destruição e degradação dos ecossistemas naturais representam a principal fonte de declínio da biodiversidade global. Os efeitos isolados e conjugados da fragmentação do habitat por desflorestação e da caça nas regiões húmidas tropicais e subtropicais têm conduzido a reduções drásticas nas densidades populacionais dos primatas. Na África Ocidental tem-se assistido à substituição das práticas agrícolas tradicionais e da caça de subsistência por uma visão económica dos recursos naturais. São muitas as reservas naturais – e até parques nacionais – totalmente transformadas em campos agrícolas que conduziram à extinção das populações de primatas locais. Aliado a isto, a intensidade da caça para consumo e venda comercial de bushmeat tem aumentado e são imensas as toneladas de biomassa perdidas anualmente nesta região. Em África, a dependência das populações por bushmeat como fonte de proteína faz com que a caça se torne a principal causa de extinção das populações de primatas na África Central e Ocidental. Sozinha, a caça traz consequências devastadoras para a fauna local, mas quando combinada com a fragmentação do habitat por desflorestação, a pressão é exacerbada. Os primatas arborícolas são um dos grupos mais afetados, estando vários classificados como espécies ameaçadas ou criticamente ameaçadas. Isolados pela fragmentação das florestas, a remoção da sua capacidade de dispersão torna-os presas fáceis para os caçadores. A redução do tamanho populacional efetivo traz consequências ao nível do património genético das espécies, nomeadamente pela perda de diversidade genética. A força da deriva genética é especialmente elevada perante tamanhos populacionais reduzidos, uma vez que as variações nas frequências alélicas se tornam mais bruscas e a probabilidade de fixação de alelos deletérios aumenta. Assim, eventos demográficos como os bottlenecks podem ter desfechos drásticos na viabilidade de populações e espécies, podendo mesmo conduzir à sua extinção ao comprometerem a capacidade das espécies se adaptarem a alterações ambientais. Deste modo, o primeiro objectivo do nosso estudo foi avaliar diversidade genética e história demográfica de duas espécies de cólobos do Parque Nacional de Taï na Costa do Marfim: Piliocolobus badius (cólobo-vermelho) e Colobus polykomos (cólobo preto-e-branco). Sendo espécies biologicamente e ecologicamente dependentes da floresta, são importantes e interessantes modelos de estudo. O Parque Nacional de Taï (TNP), classificado como Património Mundial pela UNESCO, representa o maior e melhor preservado bloco de floresta tropical húmida da África Ocidental, tendo assim um enorme potencial para suportar populações saudáveis e de elevado tamanho efectivo. Porém, o parque e as suas populações encontram-se isolados devido à desflorestação das áreas circundantes. A caça, apesar de ilegal, é uma presença constante e as espécies de cólobos são sobreexploradas a taxas que superam os 150% da sua capacidade de recuperação. Assim, o Parque Nacional de Taï pode ser considerado como um local apropriado para avaliar os efeitos isolados da caça. O Parque Nacional de Cantanhez (CNP) na Guiné-Bissau está a ser devastado pela desflorestação e os habitats de floresta encontram-se bastante fragmentados. Novamente, a caça ilegal exerce uma enorme influência sobre os primatas locais e, aliada à fragmentação do habitat, está muito perto de levar à extinção as maiores populações de Piliocolobus temminckii e de C. polykomos do país, que habitam em Cantanhez. Em 2013 e 2016, os estudos de Minhós et al. denunciaram o empobrecimento do património genético destas espécies devido a um bottleneck demográfico recentemente provocado pelas actividades antropogénicas. Assim, o segundo objectivo passou pela comparação das populações de cólobos do TNP e de dados publicados do CNP. Aliado a este objectivo está o terceiro: a quantificação dos efeitos combinados da fragmentação de habitat e caça na remoção de variabilidade genética e potencial evolutivo e viabilidade a longo prazo de populações cruciais de cólobos, que se encontram ameaçadas de extinção nos países considerados e no mundo. Incidindo nas áreas de genética da conservação e de fragmentation genetics, foram inicialmente amplificadas amostras de ADN de P. badius e C. polykomos do Parque Nacional de Taï, seguido da utilização de diversos softwares para aferir a qualidade dos procedimentos e dos dados. O passo seguinte foi a utilização de softwares para avaliar (1) a existência de dispersão desigual entre os sexos, (2) diferentes parâmetros de diversidade genética, (3) estrutura populacional e (4) história demográfica. A nossa abordagem não foi capaz de detectar a existência de dispersão significativamente desigual entre os sexos. Porém, demonstraram uma tendência para que as fêmeas sejam o sexo filopátrico e os machos responsáveis pela dispersão em ambos as espécies. Os resultados contrariam estudos prévios sobre P. badius e os motivos podem ser quer metodológicos, quer inerentes à própria ecologia da espécie. Entre todos os primatas, os colóbos possuem um dos mais complexos e variáveis sistemas sociais. A plasticidade comportamental é uma característica inerente das espécies de cólobos e pode ser a resposta para muitas questões. No que toca à diversidade genética, além da interpretação dos resultados obtidos, realizámos uma pequena revisão bibliográfica de forma a podermos compará-los com outras populações e espécies de colobíneos africanos e asiáticos. A nossa análise confirmou a esperada boa condição genética das populações e, além disso, demonstrou que possuem uma das maiores diversidades genéticas já estudadas, mesmo considerando o número de amostras como factor limitante. Por exemplo, a nossa estimativa da riqueza alélica demonstrou que os valores não são só altos, como ainda existe potencial para que sejam maiores. Esperávamos encontrar em Taï um único cluster genético, ou seja, a classificação de todos os indivíduos amostrados numa única população: foi exactamente este o resultado obtido para ambas as espécies. Na ausência de barreiras directas à dispersão, de acordo com o nosso conhecimento, não seria de esperar a presença de uma estrutura populacional mais elaborada visto que algo dificilmente o justificaria. Além disto, a pressão da caça é maior nas zonas periféricas do parque o que poderá promover o movimento para o centro e uma maior sobreposição das áreas dos diferentes grupos sociais, facilitando o fluxo genético. A ausência de referenciação geográfica das nossas amostras não permitiu um maior desenvolvimento da questão, pelo que uma abordagem ao nível da paisagem (landscape genetics) poderia trazer mais benefícios neste âmbito. Relativamente à história demográfica, os três softwares utilizados não corroboraram os resultados entre si. Foram detectados sinais de estabilidade do efectivo populacional ao longo do tempo, facilitados pelas condições e localização do habitat, que terão permitido a manutenção de elevados tamanhos populacionais ao longo de grandes períodos de tempo estará por detrás dos elevados índices de diversidade genética encontrados. Porém, este cenário não parece perdurar por muito mais tempo, pois foram igualmente detectados sinais de declínio populacional nos colobíneos do TNP, muito provavelmente, devido à pressão exercida pela caça. A comparação entre o TNP e o CNP sugere que os efeitos conjugados de fragmentação de habitat por desflorestação e da caça impulsionam o declínio a nível genético e de efectivo populacional das populações. A detecção dos sinais de bottleneck recentes em Taï resulta, muito provavelmente dos efeitos da caça e das actuais taxas de sobreexploração das espécies de colobíneos. No entanto, os resultados encontrados ao nível do efectivo populacional ainda não se terão traduzido na diversidade genética das populações. Este facto pode, porventura, ser interpretado pela vantagem dada pela ausência de fragmentação na manutenção do efectivo populacional e assim, de uma elevada diversidade genética. Por fim, esperamos que os nossos resultados realçem a importância de, no mínimo, reter os presentes efectivos populacionais de P. badius, P. temmicnkii e C. polykomos nos dois parques a fim de assegurar a sua viabilidade a longo prazo. Para que isto seja possível, é crucial desenvolver projectos de conservação da biodiversidade e restauro dos ecossistemas envolvendo as populações humanas locais e alertando para os benefícios sociais, económicos e ecológicos que poderão advir da protecção do património natural.
The destruction and degradation of the natural ecosystems represent the main source of decline of the global biodiversity. The isolated and combined effects of habitat fragmentation by deforestation and hunting in tropical and subtropical humid regions have led to drastic reductions in population density of primates. In West Africa, many natural reserves – and even national parks – have been totally converted to crop production, which has led to the local extinction of primate populations. Joining this, the hunting for consumption and commercial business of bushmeat has increased and several tons of biomass are being annually lost in the region. The arboreal primates are one of the most affected groups, with many species are considered as endangered or critically endangered. The reduction of the effective population size has consequences in the species genetic pool, namely due to the loss of genetic diversity. Hence, demographic events like the bottlenecks can have drastic effects on population and species viability, and may even lead to extinction by compromising the species ability to adapt to environmental changes. Our study aimed to analyse the genetic diversity and demographic history of the populations of two colobine species (Piliocolobus badius and Colobus polykomos) from Taï National Park (Ivory Coast). We found that each species is grouped in a single population within the park and possess one of the greatest genetic diversity among several colobine populations. However, we were able to detect positive signals of both natural ancestral and ongoing bottleneck in both species. The current decline is probably a result of anthropogenic activities. Recent studies provided insights to the impoverishment of the genetic heritage of Cantanhez National Park’s colobine populations due to a recent demographic bottleneck with anthropogenic origins, namely habitat fragmentation and hunting. We undertook a conspecific and congeneric comparison between the parks to establish a framework of fragmented versus non-fragmented habitat where hunting is a common threat. The results highlighted the fragility of Cantanhez’s colobines. Finally, we contextualized our data with the current socio-economic situation of the local populations that depend on the natural resources the parks provide. In order to achieve the conservation and the long-term viability of the focal endangered Piliocolobus badius, Piliocolobus temminckii e Colobus polykomos populations, the local human communities must be engaged in the process. Biodiversity conservation and ecosystem recovery must be conducted along with the people, promoting the awareness and the idea that many social, economic and ecological benefits may arise with the protection of the natural heritage.

Delacour's langurs (Trachypithecus delacouri), one of the six limestone langur taxa of Southeast Asia, inhabit isolated, rugged limestone karst mountains in Northern Vietnam, although the reason for their current restriction to this habitat is unclear. The occupation of karst habitats by limestone langurs has been attributed to the refuge these rocky outcrops provide in a dramatically anthropogenically-altered landscape. Conversely, several ecological explanations have been proposed to account for their distribution, though the ecology of wild Delacour's langurs had yet to be studied. In this dissertation, I quantified the foraging ecology of Delacour's langurs living on Dong Quyen Mountain in Van Long Nature Reserve, Vietnam to address if these langurs show special adaptations to limestone karst or if they are exploiting a refuge habitat into which they have been pushed. I quantified their foraging ecology by systematically investigating their diet and feeding ecology, the chemisty of their eaten leaves, and the locomotions and substrates they utilized.

From August 2007 through July 2008, I used instantaneous focal-animal sampling during all-day follows of Delacour's langurs on Dong Quyen Mountain. I collected data on activity budget, diet, and positional behavior. I also collected samples of soils and eaten and uneaten leaves which were tested for phytochemical content.

With nearly 79% leaves in the diet, 60% of which were young leaves, Delacour's langurs are among the most folivorous of studied colobines, and- along with the closely related T. leucocephalus of southern China- the most folivorous of the Asian langurs. None of the plants that were important in the Delacour's langur diet were endemic limestone plants, and therefore feeding dependence alone cannot explain the current distribution of limestone langurs on karst habitat. Langurs ate leaves with high protein:fiber ratios, and despite a high percentage of carbon in the soil, young leaves were available throughout the year and plant defenses did not seem to have a large impact on eaten leaves. Delacour's langurs spent nearly 80% of their time on rocks. Quadrupedalism was their dominant locomotor style, more than double that of climbing. Terrestrialism, however, does not adequately describe the dangerous locomotion of these langurs; they are cliff-climbers. Delacour's langurs leapt only 6% of the time, much less than other African and Asian colobines, but their morphology (intermembral index) does not suggest terrestrialism or an evolutionary adaptation for limestone karst. Delacour's langurs appear to be a flexible taxon occupying a refuge habitat into which they have pushed. However, this restricted limestone habitat does not appear limiting in resources. The population at Van Long Nature Reserve is increasing which means that- if protected- this local population can rebound. Persistent hunting for traditional medicine and the more recent emergence of quarrying limestone for cement, however, threatens their survival.

Dissertation

Summary: This dissertation is focused on observation of locomotion two groups of mantled guereza in ZOO Prague and ZOO Usti nad Labem. The observation took place in the summer of 2011. The locomotion behavior is for better clarity presented by tables, diagrams and detailed description of the breeding facilities of both groups. The work contains list of all species of guereza, including all subspecies of mantled guereza. Key words: primates, old world monkeys, Colobinae, black and white colobus monkey, mantled guereza, threat, behavior, breeding in the zoo.

Le syndrome CHARGE est une maladie génétique rare dont l’acronyme désigne les principales anomalies initialement identifiées pour décrire ce syndrome : colobome, problèmes cardiaques, atrésie des choanes, retard mental et de développement, anomalies génitales et défauts aux oreilles. Les patients présentent des combinaisons hautement variables d’anomalies et ce même entre individus d’une même famille. La principale cause de ce syndrome est une mutation du gène CHD7, mais de nouveaux gènes dont la mutation peut également engendrer ce syndrome, tel FAM172A , ont récemment été identifiés. Le modèle murin Toupee porte une mutation dans le gène Fam172a et présente les principales caractéristiques du syndrome CHARGE. Fait intéressant, si FVBToupee présente dans une forte proportion le colobome oculaire, 55% des individus B6ToupeeTg/Tg et 16% des individus B6ToupeeTg/+ présentent de la microphtalmie et de l’anophtalmie. Ces anomalies oculaires ont tout d’abord été caractérisées. Les études menées ont notamment permis d’identifier que chez B6Toupee la microphtalmie et l’anophtalmie sont beaucoup plus fréquentes dans l’œil droit et qu’elles se déclinent en plusieurs degrés variables d’atteinte au globe oculaire. Par la suite, l’étude comparative des modèles ToupeeTg/Tg et Chd7Gt/+a été réalisée dans les fonds génétiques FVB et C57Bl/6. Des différences significatives de pénétrance de même que des divergences phénotypiques ont permis de déterminer que l’identité du gène à l’origine du syndrome CHARGE et que le fond génétique modulent tous deux le développement phénotypique du syndrome CHARGE. Finalement, l’étude de doubles hétérozygotes FVBToupeeTg/+ ;Chd7Gt/+ a permis de confirmer une interaction génétique modérée entre Fam172a et Chd7 tandis que l’investigation de la mortalité néonatale chez Chd7Gt/+ a permis de suspecter des problèmes d’alimentation.
CHARGE syndrome is a rare genetic disease for which the acronym stands for the main characteristics initially identified to describe the syndrome: coloboma, heart problems, choanal atresia, retarded growth and development, genital anomalies and ear defects. Patients present highly variable combinations of anomalies, even between members of the same family. The main cause of this syndrome is a mutation in the CHD7 gene, but new genes whose mutation can also give rise to this syndrome, such as FAM172A, were recently identified. The Fam172a gene is mutated in the Toupee mouse model, which presents the main characteristics of CHARGE syndrome. Interestingly, while FVBToupee animals present coloboma in a strong proportion, 55% of B6ToupeeTg/Tg individuals and 16% of B6ToupeeTg/+ individuals present microphthalmia and anophthalmia. First, detailed characterization of these ocular anomalies revealed that microphthalmia and anophthalmia are much more frequent in the right eye of B6Toupee mice, with varying degrees of severity. Then, comparative analysis of ToupeeTg/Tg and Chd7Gt/+models in FVB and C57Bl/6 genetic backgrounds further revealed significant differences in penetrance and phenotypic presentation, suggesting that the identity of the causative gene and the genetic background both modulate phenotypic outcome of CHARGE syndrome. Finally, characterization of FVBToupeeTg/+;Chd7Gt/+ double heterozygotes confirmed a moderate genetic interaction between Fam172a and Chd7 while investigations of Chd7Gt/+ neonatal mortality allowed to suspect feeding problems.