Shared Ancestry and Signatures of Recent Selection in Gotland Sheep

Gotland sheep, a breed native to Gotland, Sweden (an island in the Baltic Sea), split from the Gute sheep breed approximately 100 years ago, and since, has probably been crossed with other breeds. This breed has recently gained popularity, due to its pelt quality. This study estimates the shared ancestors and identifies recent selection signatures in Gotland sheep using 600 K single nucleotide polymorphism (SNP) genotype data. Admixture analysis shows that the Gotland sheep is a distinct breed, but also has shared ancestral genomic components with Gute (similar to 50%), Karakul (similar to 30%), Romanov (similar to 20%), and Fjallnas (similar to 10%) sheep breeds. Two complementary methods were applied to detect selection signatures: A Bayesian population differentiation F-ST and an integrated haplotype homozygosity score (iHS). Our results find that seven significant SNPs (q-value < 0.05) using the F-ST analysis and 55 significant SNPs (p-value < 0.0001) using the iHS analysis. Of the candidate genes that contain significant markers, or are in proximity to them, we identify several belongings to the keratin genes, RXFP2, ADCY1, ENOX1, USF2, COX7A1, ARHGAP28, CRYBB2, CAPNS1, FMO3, and GREB1. These genes are involved in wool quality, polled and horned phenotypes, fertility, twining rate, meat quality, and growth traits. In summary, our results provide shared founders of Gotland sheep and insight into genomic regions maintained under selection after the breed was formed. These results contribute to the detection of candidate genes and QTLs underlying economic traits in sheep.

Automated summary

The Gotland sheep, a breed from Sweden, has unique ancestral genomic components while also sharing genes with other breeds. This study identified selection signatures in the breed and highlighted candidate genes related to wool quality, horned phenotypes, fertility, and other economically important traits in sheep.