Spatiotemporal genetic structure of the Limousin breed in France

Master

English. Background: Climate change is affecting population and ecosystems, and increases of temperature and extreme events are expected in the coming years. Changes in our production systems are needed, and agroecological transition appears as a solution. One key feature of it is genetic diversity at different levels since they are well adapted to their local environments. Therefore, the diversity of local breeds must be considered as a valuable resource to cope with changing environments. However, local breeds face issues like genetic drift and inbreeding due to their low population size. Thus, their potential as a valuable genetic resource should be evaluated.Methods: Using 25961 animals genotyped with a 50K SNP array we investigated the functional and neutral genetic diversity of the Limousin French local beef cattle breed. We evaluated its genetic management by studying the evolution and current levels of inbreeding. and the global spatial genetic structure. Finally, we checked for local adaptation to dry and hot conditions and detection of genomic regions involved in that process.Results: Good levels of genetic diversity were found in the Limousin breed, with no difference between polled and horned animals. Moreover, a good connectivity between individuals was found, with no global or local spatial genetic structure. Finally, environmental data (maximum temperature and mean vapor pressure deficit in spring and summer) were found to explain part of genetic variance (0.3%) and 2 genes (TLR4 and SLC24A4) involved in climate related functions were highlighted.Conclusions: Limousin breed exhibited a satisfying level of inbreeding, a good connectivity, and does not face issues similar to those faced by other local breeds. Signs of adaptation to climate were found, and further studies would be necessary to implement these genes in future breeding programs.