Phenotypes

The double-muscle trait in cattle is characterised by an increase in muscle mass of approx 20%, resulting in substantially higher meat yield, a higher proportion of expensive cuts of meat, and lean and very tender meat, for which a substantial premium is paid. The trait is autosomal recessive, and the locus has been given the symbol mh. It occurs at such a high frequency in Piedmontese and Belgian Blue cattle that it is characteristic of these...

Using the comparative positional candidate gene approach (based on similarities of the bovine clinical signs with the homologous human disorder, and the mapping results mentioned above), Houweling et al. (2006; Biochim Biophys Acta 1762:890-7) sequenced CLN5 genomic DNA and cDNA from affected and normal Devon cattle, identifying the causal mutation as a "single base duplication in exon 4 of bovine CLN5 (c.662dupG) . . . . This duplication resu...