Abstract #T102

# T102
Selection signature analysis in Holstein cattle identified genes known to affect reproduction.
Li Ma1, Tad S. Sonstegard2, Curtis Van Tassell2, John B. Cole2, George R. Wiggans2, Brian A. Crooker3, F. Abel Ponce de Leon3, Yang Da*3, 1Department of Animal and Avian Sciences, University of Maryland, College Park, MD, 2Animal Genomics and Improvement Laboratory, ARS-USDA, Beltsville, MD, 3Department of Animal Science, University of Minnesota, Saint Paul, MN.

Using direct comparison of 45,878 SNPs between a group of Holstein cattle unselected since 1964 and contemporary Holsteins that on average take 30 d longer for successful conception than the 1964 Holsteins, we conducted selection signature analyses to identify genome regions associated with dairy fertility. Several genes known to affect reproduction were located in or near genome regions with strong selection signals. These genes include the fibroblast growth factor 1 gene (FGF1) on Chr07; the follicle stimulating hormone receptor gene (FSHR) and the luteinizing hormone choriogonadotropin receptor gene (LHCGR) on Chr11; the KIT ligand gene (KITLG or KITL), the fibroblast growth factor 6 and 23 genes (FGF6 and FGF23) and the cyclin D2 gene (CCND2) on Chr05; the placental growth factor gene (PGF or PLGF) and the estrogen-related receptor β gene (ESRRB) 2Mb downstream of PGF on Chr10; and the prolactin receptor gene (PRLR) on Chr20. The selection signal for the region containing FGF1 was among the strongest selection signals we observed. According to the literature on these genes, FGF1 is involved in broad mitogenic and cell survival activities including embryonic development, PGF plays a key role in embryogenesis, ESRRB plays an essential role in placenta development, FSHR is necessary for follicular development and is expressed on the granulosa cells that are closely associated with the developing female gamete in the ovary of mammals, and LHCGR is necessary for follicular maturation and ovulation. Mouse knockout models showed that FSHR, KITLG, CCNG2, and PRLR were involved in female fertility proteins. These known gene functions related to reproduction and the fact that these genes were in or near chromosome regions with strong selection signals indicate that these genes could be involved in the vast difference in fertility between contemporary Holsteins and the 1964 Holsteins.

Key Words: fertility, selection signature, Holstein