Frequencies of genes for coat colour and horns in Nordic cattle breeds

Gene frequencies of coat colour and horn types were assessed in 22 Nordic c attle breeds in a project aimed at establishing genetic profiles of the bre eds under study. The coat colour loci yielding information on genetic varia tion were: extension, agouti, spotting, brindle, dun dilution and colour si ded. The polled locus was assessed for two alleles. A profound variation be tween breeds was observed in the frequencies of both colour and horn allele s, with the older breeds generally showing greater variation in observed co lour, horn types and segregating alleles than the modern breeds. The corres pondence between the present genetic distance matrix and previous molecular marker distance matrices was low (r = 0.08 - 0.12). The branching pattern of a neighbour-joining tree disagreed to some extent with the molecular dat a structure. The current data indicates that 70% of the total genetic varia tion could be explained by differences between the breeds, suggesting a muc h greater breed differentiation than typically found at protein and microsa tellite loci. The marked differentiation of the cattle breeds and observed disagreements with the results from the previous molecular data in the topo logy of the phylogenetic trees are most likely a result of selection on phe notypic characters analysed in this study.