Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Proceedings
Publication Acceptance Date: 1/11/1997
Publication Date: N/A
Technical Abstract: DNA microsatellites were used to detect loci affecting quantitative traits in the U.S. dairy cattle population. Seventeen U.S. Holstein families each with at least 29 progeny-tested sons were analyzed. The 17 grandsires and 1437 of their sons were genotyped for 32 genetic markers located on 19 of the 29 autosomes. From 16 to 204 sons were genotyped per family, and more than 100 sons were genotyped for six families. The sons' daughter yield deviations for milk, fat, and protein production, fat and protein percentage, productive herdlife, and somatic cell score were analyzed. The marker allele effect was significant at P<0.01 for four genetic markers. MGTG7 affected somatic cell score, and ILSTS28 affected protein percentage. TGLA263 and CSSM66 had significant effects on more than one milk production trait, but the effects on fat percentage were greatest for both loci. The effect of CSSM66 on chromosome 14 was significant at P<10^-7. The within-family contrast for family 4 was 0.13%. Using both single-marker maximum likelihood and interval mapping with a second linked marker, BM302, the quantitative locus mapped adjacent to CSSM66. The estimated allele substitution effect was 0.46 phenotypic standard deviations, about 20% of the genetic variance or 10% of the phenotypic variance. For 7 Israeli sires, 1498 daughters were genotyped for CSSM66. The marker allele effect was only significant for fat percentage at P<0.001. The within-family contrast was significant only for family 2 at P<0.0001, and the profile of effects and estimated map location was similar to that of U.S. family 4. Thus, the same quantitative trait locus was detected in both populations.