Association of a single nucleotide polymorphism in SPP1 with growth traits and twinning in a cattle population selected for twinning rate

¹ USDA, ARS, US Meat Animal Research Center, Clay Center, NE 68933-0166
² Molecular Genetics Research Unit, U. S. Meat Animal Research Center, Clay Center, Nebraska, United States

^* To whom correspondence should be addressed. E-mail: allan{at}email.marc.usda.gov.

	Abstract

Continued validation of genetic markers for economically important traits is crucial to establishing marker-assisted selection as a tool in the cattle industry. The objective of the present study was to evaluate the association of a single nucleotide polymorphism (T₉/T₁₀) in the Osteopontin gene (SPP1) with growth rate in a large cattle population spanning multiple generations and representing alleles from 12 founding breeds. This population has been maintained at the U.S. Meat Animal Research Center since 1981 and subjected to selection for twinning rate. Phenotypic records for this population included twinning rate and ovulation rate, providing an opportunity to examine potential effects of SPP1 genotype on reproductive traits. A set of 2,701 animals were genotyped for the T₉/T₁₀ polymorphism at SPP1; the genotypic data, including previously genotyped markers on chromosome 6 (BTA6), were used in conjunction with pedigree information to estimate genotypic probabilities for all 14,714 animals with phenotypic records. The genotypic probabilities for females were used to calculate independent variables for regressions of additive, dominance and imprinting effects. Genotypic regressions were fit as fixed effects in a mixed model analysis where each trait was analyzed in a two-trait model where single births were treated as a separate trait from twin births. Association of the SPP1 marker with birth weight (P < 0.006), weaning weight (P < 0.007), and yearling weight (P < 0.003) is consistent with previously reported effects of SPP1 genotype on yearling weight. Our data supports the conclusion that the marker successfully tracks functional alleles affecting growth in cattle. The previously undetected effect of the marker on birth and weaning weight suggests that the SPP1 marker may explain a portion of the phenotypic variance explained by QTL for birth and hot carcass weights on BTA6.

Key Words: genetic markers, MAS, osteopontin, twinning

This article has been cited by other articles:

				S. E. Echternkamp, R. M. Thallman, R. A. Cushman, M. F. Allan, and K. E. Gregory Increased calf production in cattle selected for twin ovulations J Anim Sci, December 1, 2007; 85(12): 3239 - 3248. [Abstract] [Full Text] [PDF]