Phenotypes

Drögemüller et al. (2011) identified a likely causal variant in Tyrolean Grey cattle as the synonymous c.2229C>T SNP, which "is located within a putative exonic splice enhancer (ESE) and the variant allele leads to partial retention of the entire intron 19 and a premature stop codon in the aberrant MFN2 transcript. Thus we have identified a highly unusual splicing defect, where an exonic single base exchange leads to the retention of the pr...

To date, all cases of this lethal disorder in cattle appear to be due to the same mutation, namely a nonsense mutation in the 5th of 9 exons of the ASS gene. Normal bovine ASS is a peptide containing 412 amino acids; the mutation occurs in the 86th codon.

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.

Adams et al. (2012) revealed the causal mutation of HH1 as "a nonsense mutation in APAF1 . . . , which is predicted to truncate approximately one-third of the encoded APAF1 protein". Because functional APAF1 peptide is required for embryo development, homozygosity for this allele results in natural spontaneous abortion, and, consequently, perceived reduced fertility in carrier bulls that happen to be mated to carrier cows. Adams et al. (2016) ...

By cloning and sequencing a very likely comparative candidate gene (based on the same disorder in humans), Shuster et al. (1992; PNAS) showed that this disorder in Holstein cattle is due to a missense mutation (c.383A>G) in the CD18 gene, now known as ITGB2. This mutation was confirmed in Daetwyler et al. (2014)'s analysis of whole-genome sequence data from 234 cattle, including key ancestors of the Holstein-Friesian, Fleckvieh and Jersey b...

This single-locus autosomal dominant trait confers increased thermotolerance within the breeds in which it originated (Senepol and Carora; Olsen et al., 2003) and also within Hosteins, into which it was introgressed (Dikmen et al., 2008; 2014). In the USA, FDA determined in March 2022 that beef cattle with a genome edit to the PRLR gene and their offspring do not raise any safety concerns. "Based on the safety of consumption of meat from conve...