title: Evidence for multiple alleles at the DGAT1 locus better explains a quantitative trait locus with major effect on milk fat content in cattle.
abstract: A quantitative trait locus (QTL) for milk fat percentage has been mapped consistently to the centromeric region of bovine chromosome 14 (BTA14). Two independent studies have identified the nonconservative mutation K232A in the acylCoA-diacylglycerol-acyltransferase 1 (DGAT1) gene as likely to be causal for the observed variation. Here we provide evidence for additional genetic variability at the same QTL that is associated with milk fat percentage variation within the German Holstein population. Namely, we show that alleles of the DGAT1 promoter derived from the variable number of tandem repeat (VNTR) polymorphism are associated with milk fat content in animals homozygous for the allele 232A at DGAT1. Our results present another example for more than two trait-associated alleles being involved in a major gene effect on a quantitative trait. The segregation of multiple alleles affecting milk production traits at the QTL on BTA14 has to be considered whenever marker-assisted selection programs are implemented in dairy cattle. Due to the presence of a potential transcription factor binding site in the 18mer element of the VNTR, the variation in the number of tandem repeats of the 18mer element might be causal for the variability in the transcription level of the DGAT1 gene.
authors.affiliation: Forschungsbereich Molekularbiologie, Forschungsinstitut für die Biologie landwirtschaftlicher Nutztiere, 18196 Dummerstorf, Germany.
authors.forename: Christa
authors.initials: C
authors.lastname: Kühn
authors.forename: Georg
authors.initials: G
authors.lastname: Thaller
authors.forename: Andreas
authors.initials: A
authors.lastname: Winter
authors.forename: Olaf R P
authors.initials: OR
authors.lastname: Bininda-Emonds
authors.forename: Bernhard
authors.initials: B
authors.lastname: Kaupe
authors.forename: Georg
authors.initials: G
authors.lastname: Erhardt
authors.forename: Jörn
authors.initials: J
authors.lastname: Bennewitz
authors.forename: Manfred
authors.initials: M
authors.lastname: Schwerin
authors.forename: Ruedi
authors.initials: R
authors.lastname: Fries
mesh_terms: D000217:Acyltransferases / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D017931:DNA Primers; D051048:Diacylglycerol O-Acyltransferase; D005260:Female; D005819:Genetic Markers; D014644:Genetic Variation; D008055:Lipids / Q000032:analysis*; D008297:Male; D051379:Mice; D008892:Milk / Q000737:chemistry*; D040641:Quantitative Trait Loci
chemical_list: D017931:DNA Primers; D005819:Genetic Markers; D008055:Lipids; D000217:Acyltransferases; C494882:Dgat1 protein, mouse; D051048:Diacylglycerol O-Acyltransferase