Littérature scientifique sur le sujet « Animal migration ; Trade routes ; Phylogeography »

SUMMARYPhylogeography of parasites and microbes is a recent field. Phylogeographic studies have been performed mostly to test three major hypotheses that are not mutually exclusive on the origins and distributions of human parasites and microbes: (1) the “out of Africa” pattern where parasites are supposed to have followed the dispersal and expansion of modern humans in and out of Africa, (2) the “domestication” pattern where parasites were captured in the domestication centres and dispersed through them and (3) the “globalization” pattern, in relation to historical and more recent trade routes. With some exceptions, such studies of human protozoans, helminths and ectoparasites are quite limited. The conclusion emphasizes the need to acquire more phylogeographic data in non-Occidental countries, and particularly in Asia where all the animal domestications took place.

Critics of international trade agreements often cast them as threats to human health, and they can point to some sobering warnings from world history. Infectious diseases have swept across political boundaries, carried by traders, colonists, and other agents of globalization. Transnational epidemics have laid economies low, undermining political stability. The spread of viruses and bacteria to peoples previously unexposed and therefore lacking immunity has decimated populations and changed the political course of continents. Trade, exploration, and warfare have repeatedly produced encounters between peoples at different levels of agricultural and technological development. Often, the results have been devastating for the disadvantaged group — economic marginalization, loss of sovereignty and culture, and collapse of public health. Yet the rise of civilization — plant and animal domestication, division of labor, technology, and resulting prosperity — was powered in large part by movement of products and knowledge along routes of trade and migration.

Animal vesicular diseases are rather widespread in the world. Transboundary vesicular diseases are mainly registered in African and Asian countries. They primarily include foot and mouth disease, sheep and goat pox, peste des petits ruminants, lumpy skin disease, swine vesicular disease, vesicular stomatitis, as well as relatively new Seneca Valley virus infection. The transboundary spread of vesicular diseases is mainly caused by legal and illegal movements of animals, animal products, feeds, live vaccines; migration of wild animals across the borders from neighboring countries and passive mechanical transmission of infection. The risk of vesicular disease agent introduction with legal import of live animals into the territory of the Russian Federation is minimal. Most likely, the causative agent can be introduced when livestock products are illegally imported from the following countries: China, Turkey, India, Mongolia, Iran, Kazakhstan, etc. Violations of foreign trade regulations pose a direct threat to the epidemic situation and economic security of Russia. There is a possibility of the introduction of vesicular agents with animal feed imports into the country since some viruses can potentially survive for a long time in some ingredients. Taking into account the fact that some neighboring countries are infected with vesicular diseases, the threat of infection introduction into Russia through migration of wild animals along the North Caucasian, Central Asian and Far Eastern routes still remains.

Abstract Reconstructing ancestral characters and traits along a phylogenetic tree is central to evolutionary biology. It is the key to understanding morphology changes among species, inferring ancestral biochemical properties of life, or recovering migration routes in phylogeography. The goal is 2-fold: to reconstruct the character state at the tree root (e.g., the region of origin of some species) and to understand the process of state changes along the tree (e.g., species flow between countries). We deal here with discrete characters, which are “unique,” as opposed to sequence characters (nucleotides or amino-acids), where we assume the same model for all the characters (or for large classes of characters with site-dependent models) and thus benefit from multiple information sources. In this framework, we use mathematics and simulations to demonstrate that although each goal can be achieved with high accuracy individually, it is generally impossible to accurately estimate both the root state and the rates of state changes along the tree branches, from the observed data at the tips of the tree. This is because the global rates of state changes along the branches that are optimal for the two estimation tasks have opposite trends, leading to a fundamental trade-off in accuracy. This inherent “Darwinian uncertainty principle” concerning the simultaneous estimation of “patterns” and “processes” governs ancestral reconstructions in biology. For certain tree shapes (typically speciation trees) the uncertainty of simultaneous estimation is reduced when more tips are present; however, for other tree shapes it does not (e.g., coalescent trees used in population genetics).

AbstractPost-glacial survival, potential migration routes, genetic diversity and phylogeography of the boreal moss species Rhytidium rugosum have been studied. This species is considered to be one of glacial relics of the wide but scattered Holarctic range. According to molecular data sampling from the selected European, American and Asian populations high genetic diversity of this species is present, even if this species is mostly sterile and produced sex organs extremely rarely and spread mostly asexually. Analysing the internal transcribed spacer (ITS) of the nuclear ribosomal DNA, it can be concluded that the populations of this species survived glaciations in various places in Europe and settled and re-settled present range space in various times from various refuges.

The Indian Ocean represents one of the oldest exchange networks connecting South-East-Asia with India, the Arabian peninsula, as far as Africa in the West. Since the beginning of the Common Era, extensive trade between geographically distant and culturally diverse people enabled the transmission of not only new technologies, exotic goods and food items, but also diverse plant and animal species. Although archaeological remains, particularly from the 1st millennium AD, reflect an intensification of maritime connectivity across the Indian Ocean, the exact routes of travel and trade across this vast area in early times are still subject to discussion. This thesis presents different projects that aim to assess the potential of using commensal animals, such as the house mouse Mus musculus, the black rat Rattus rattus, and the Asian house gecko Hemidactylus frenatus, as proxies to infer pathways of human travel and trade. Commensal species are usually small animals, that live in close association with humans and opportunistically exploit their habitat and food sources. Utilisation of these new resources has led to a close relationship between humans and certain species, and thus favoured their global distribution due to translocations through humans. Therefore, genetic analyses from modern and museum samples of the species in question have been employed, and embedded in a phylogeographic approach. This integrative methodology connects genealogy and geography, with the aim to reconstruct evolutionary, demographic, and biogeographic processes that led to the contemporary distribution of genetic lineages of the commensal species and subsequently mirrors travel routes of the humans who carried them. The incorporation of ancient DNA analysis provides a powerful method, not only enabling the detection of source populations, but direct monitoring of their genetic change through time. Given that people have moved them around for a long time, undirected distribution pattern of populations were expected for each species. However, the results demonstrate that several unique and geographically restricted lineages have been identified, reflecting past human-mediated translocation throughout the Indian and Pacific Ocean from the 1st millennium AD onwards.