Beschreibung:
<jats:title>Summary</jats:title><jats:p>Double muscling is an inherited condition in cattle characterised by large increases in muscle mass. Mutations in the <jats:italic>myostatin</jats:italic> (<jats:styled-content style="fixed-case"><jats:italic>MSTN</jats:italic></jats:styled-content>) gene, responsible for double muscling, were targeted in this study to estimate the time since the most recent common ancestor (<jats:styled-content style="fixed-case">TMRCA</jats:styled-content>) for <jats:italic>Q204X</jats:italic> (p.Gln204*), <jats:italic>E226X</jats:italic> (p.Glu226*), <jats:italic>821del11</jats:italic> (c.821del11), <jats:italic>E291X</jats:italic> (p.Glu291*), <jats:italic>C313Y</jats:italic> (p.Cys313Tyr) and the more phenotypically moderate <jats:italic>F94L</jats:italic> (p.Phe94Leu) mutation. Genetic variability was examined in eight regions upstream and downstream of the <jats:styled-content style="fixed-case"><jats:italic>MSTN</jats:italic></jats:styled-content> locus. The molecular distance of the homozygous region associated with each <jats:styled-content style="fixed-case"><jats:italic>MSTN</jats:italic></jats:styled-content> allele was used to estimate the <jats:styled-content style="fixed-case">TMRCA</jats:styled-content>. Long homozygous segments were associated with the <jats:styled-content style="fixed-case"><jats:italic>MSTN</jats:italic></jats:styled-content> alleles (mostly > 2 Mb), compared to short segments (130 kb) for cattle wild type at the double muscling and <jats:italic>F94L</jats:italic> sites. Estimates of time indicated that each <jats:styled-content style="fixed-case"><jats:italic>MSTN</jats:italic></jats:styled-content> allele had a recent common ancestor (<400 years ago). The results from this study, and the increasing frequency of these <jats:styled-content style="fixed-case"><jats:italic>MSTN</jats:italic></jats:styled-content> alleles in some cattle breeds, demonstrate recent positive selection.</jats:p>