Mutations in BMPR-IB and BMP-15 genes are associated with litter size in Small Tailed Han sheep (Ovis aries)

¹ Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100094, China
² College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China

^* To whom correspondence should be addressed. E-mail: mxchu{at}263.net.

	Abstract

The Small Tailed Han is a prolific local sheep breed in China. The bone morphogenetic protein receptor IB (BMPR-IB) gene, which affects the fecundity of Booroola Merino sheep, and the bone morphogenetic protein 15 (BMP-15) gene, which affects the fecundity of Inverdale, Hanna, Belclare, Cambridge, and Lacaune sheep, were studied as candidate genes for the prolificacy of Small Tailed Han sheep. Single nucleotide polymorphisms of BMPR-IB and BMP-15 genes were detected in Small Tailed Han ewes (n = 188) by PCR-RFLP. The combined effect of the two genes on the prolificacy of Small Tailed Han sheep was studied. The results indicated that the same FecB mutation (Q249R) occurred in the BMPR-IB gene in Small Tailed Han ewes as found in Booroola Merino ewes. The Small Tailed Han ewes with genotypes FecB^B/FecB^B and FecB^B/FecB⁺ had 1.40 (P < 0.01) and 1.11 (P < 0.01) more lambs, respectively, than those with genotype FecB⁺/FecB⁺. The same FecX^G mutation (Q239Ter) of the BMP-15 gene was found in Small Tailed Han ewes as in both Belclare and Cambridge ewes. The Small Tailed Han ewes with the heterozygous mutant FecX^G/FecX⁺ had 0.55 (P < 0.01) more lambs than those with the wild type FecX⁺/FecX⁺. The Small Tailed Han ewes carrying mutations in both BMPR-IB and BMP-15 genes had greater litter size than those with either mutation alone. In view of our results, marker-assisted selection using both BMPR-IB and BMP-15 genes is warranted to increase litter size in sheep and will be of considerable economic value to mutton producers.

Key Words: sheep, prolificacy, bone morphogenetic protein receptor IB gene, bone morphogenetic protein 15 gene