Genome-wide scan for bovine milk-fat composition. I. Quantitative trait loci for short- and medium-chain fatty acids.
A genome-wide scan was performed to identify quantitative trait loci (QTL) for short- and medium-chain fatty acids (expressed in wt/wt %). Milk samples were available from 1,905 cows from 398 commercial herds in the Netherlands, and milk-fat composition was measured by gas chromatography. DNA was available from 7 of the paternal half-sib families: 849 cows and their 7 sires. A genetic map was constructed comprising 1,341 SNP and 2,829 cM, with an average information content of 0.83. Multimarker interval mapping was used in an across-family regression on corrected phenotypes for the 7 half-sib families. Four QTL were found: on Bos taurus autosome (BTA) 6, a QTL was identified for C6:0 and C8:0; on BTA14, a QTL was identified for fat percentage, all odd-chain fatty acids, and C14:0, C16:0, C16:1, and their unsaturation indices; on BTA19, a QTL affected C14:0; and on BTA26, a QTL was identified for the monounsaturated fatty acids and their unsaturation indices. The QTL explained 3 to 19% of phenotypic variance. Furthermore, 49 traits with suggestive evidence for linkage were found on 21 chromosomes. Additional analyses revealed that the QTL on BTA14 was most likely caused by a mutation in DGAT1, whereas the QTL on BTA26 was most likely caused by a mutation in the SCD1 gene. Quantitative trait loci that affect specific fatty acids might increase the understanding of physiological processes regarding fat synthesis and the position of the causal genes.
Stoop
W M
WM
Animal Breeding and Genomics Centre, Wageningen University, Wageningen, the Netherlands. Marianne.Stoop@crv4all.com
Schennink
A
A
Visker
M H P W
MH
Mullaart
E
E
van Arendonk
J A M
JA
Bovenhuis
H
H
D000818:Animals; D002417:Cattle / Q000235:genetics*; D005223:Fats / Q000737:chemistry*; D005227:Fatty Acids / Q000235:genetics*; D005260:Female; D055106:Genome-Wide Association Study; D008297:Male; D008892:Milk / Q000737:chemistry*; D010641:Phenotype; D040641:Quantitative Trait Loci / Q000235:genetics*
D005223:Fats; D005227:Fatty Acids