Study On Genetic Mechanism Of Reproduction In Sheep

Understanding the genetic mechanism of reproduction is a major basis for improving the litter sizes and production efficiency in sheep. Since the south migration of Mongolian sheep in late Song Dynasty, it has been a thousand of years since the formation of high fecundity groups including Small Tail Han sheep and Hu sheep and low fecundity groups including Sunite sheep and Ujimqin sheep who are all originated from Mongolian sheep. Under this genetic background, it is possible to screen the genetic variations responsible for reproduction using next generation sequencing. In this study, we resolved the genetic mechanism of reproduction by comparing the variations among four lines and integrating the transcriptome data of follicular development from other breeds and genotyping data initially. The main results are as follows:(1) the divergence among Mongolian sheepWe revealed forty-seven regions which have significant differentiation between high fecundity groups and low fecundity groups using ROH and Fst by sliding windows, further functional analysis addressed six key candidate genes (eg. DACH2, AMH, ADAM21. et) representing the biological process of reproduction.(2) expression correlation analysisFour core candidate genes (eg. ECH1, IGF1R. et) and seven quantitative trait loci associated with follicular development were proposed by expression correlation analysis.(3) screening the SNPs responsible reproductionWe carried out 145 SNPs which can be considered into low-density chip for addressing the problem of reproduction performance in sheep breeding using reduced-representation genome sequencing.In this study, we firstly explored the molecular mechanism of reproduction combining multiple genomic technologies. This study will have provided new resource in future research in functional genes and validation, which also have major implications in mapping genes associated with reproduction and breeding program.