Phenotypes

By cloning and sequencing a very likely comparative candidate gene (based on the homologous human disorder), Dennis et al. (2000) identified two causal mutations in Brahman cattle, namely a frameshifting 2-bp deletion (c.1057delTA; the "E7" mutation) and a nonsense mutation (c.1783C>T; p.Arg595Ter; the "E13" mutation) in the bovine GAA gene; and a 2-bp frameshifting deletion (c.2454delCA; the "E18" mutation) in Shorthorns.

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...

Hiltpold et al. (2022) investigated a Brown Swiss bull with low semen quality: "The genome of this bull was sequenced at a 12× coverage to investigate a possible genetic cause. Comparing the sequence variant genotypes of this bull with those from 397 fertile bulls revealed a 1-bp deletion in the coding sequence of the QRICH2 gene which encodes the glutamine rich 2 protein, as a compelling candidate causal variant. This 1-bp deletion causes a f...

Cloning and sequencing of the bovine gene encoding molybdopterin cofactor sulfurase (MCSU, now called MOCOS) in normal and affected cattle, by Watanabe et al. (2000), revealed the causal mutation to be a 3bp deletion (c.769_771delTAC) of codon 257 (deleting Tyr) in the MOCOS gene (omia.variant:446). Murgiano et al. (2016) discovered a different mutation in the MUCOS gene as the likely cause in Tyrolean Grey cattle: "1 bp deletion in the molybd...