ARS | Publication request: Forty Years Of Artificial Selection In U.S. Holstein Cattle Had Genome-wide Signatures

Submitted to: World Congress of Genetics Applied in Livestock Production
Publication Type: Proceedings
Publication Acceptance Date: May 9, 2010
Publication Date: August 1, 2010
Citation: Sonstegard, T.S., Ma, L., Van Tassell, C.P., Kim, E., Cole, J.B., Wiggans, G.R., Crooker, B.A., Mariani, B.D., Gerber, J.R., Fahrenkrug, S.C., Liu, G., Da, Y. 2010. Forty Years Of Artificial Selection In U.S. Holstein Cattle Had Genome-wide Signatures. World Congress of Genetics Applied in Livestock Production.

Interpretive Summary: The North American Dairy industry has successfully selected animals for superior milk yield over the past 40 years, nearly doubling output per cow. This selection for improvement in production has been derived from estimates of genetic merit. In this report, we describe what regions of the genome underlie improved milk production by genotyping a line of cattle which has remained under neutral selection since 1964. Comparison of the genome structure of these animals to modern high-producing animals revealed that as much as 22% of the genome has significantly been selected for improved milk production. This increase in production did come at the cost, because of the enrichment of genome regions negatively affecting reproduction.

Technical Abstract: Genome signatures of 40 years of artificial selection in U.S. Holstein cattle were identified by comparing allele frequencies and extended haplotype homozygosity in a Holstein resource population composed of a contemporary group, a group born in 1975-1985, and a group unselected since 1964. Results showed that 40 years of artificial selection caused significant genome-wide changes as characterized by allele frequency differences between selected and unselected groups and by elevated EHH distances in the contemporary group. Many of the selection signatures contained or were next to significant QTL effects on 31 dairy traits of contemporary U.S. Holstein cattle.