Identification of a missense mutation in the bovine ABCG2 gene with a major effect on the QTL on chromosome 6 affecting milk yield and composition in Holstein cattle

Conservation of the 5^th extracellular domain of ABCG2 protein in mammals. The ClustalW (Thompson et al. 1994) alignment of predicted amino acid sequences of nine orthologous ABCG2 genes is shown. Identity and similarity between the amino acid sequences are indicated by black and gray boxes, respectively. White boxes indicate nonconservative amino acid changes between the proteins. Dashes indicate gaps introduced by the alignment program. The position of 581Y in Bos taurus for which the sires heterozygous for the QTL were 581Y/581S is indicated by an arrow. A conserved phenylalanine residue is located in this position for most of the other mammals.