Identification and analysis of single nucleotide polymorphisms in the myosin VA (MYO5A) gene and its exclusion as the causative gene of the dilute coat colour locus in rabbit

Abstract

Classical genetic studies have identified different coat colour loci in rabbit and comparative analyses have established corresponding loci across species. In particular, the rabbit dilute locus is determined by a recessive coat colour mutation that modifies the basic colours influenced by the agouti and extension mutations. In mice, similar phenotypic effects are determined by a similarly named locus. This locus encodes the myosin VA (Myo5a) gene, whose protein product is an unconventional myosin that plays an essential role in melanosome transport in the melanocytes. We selected the same gene as a strong candidate for explaining the dilute coat colour in rabbit. To this end, 1399 bp were re-sequenced, spanning 4 exons out of 41 exons and portions of intronic regions of the rabbit MYO5A gene to identify polymorphisms that could be useful to confirm or exclude this gene as causative of the rabbit dilute locus. Nine polymorphisms were identified, one of which was used to follow the segregation of the blue and black colours in a Checkered Giant F1 family. The single nucleotide polymorphism (SNP) analysed did not co-segregate with the 2 colours. These results excluded the MYO5A gene as determinant of the dilute locus in rabbit. The 2 alleles of this SNP were also present in several other breeds with different coat colours, further indicating that this marker is not associated with the dilute mutation in rabbits. Other candidates should be investigated to identify the causative gene of this locus in rabbit.

Rabbit Genetic Resources Can Provide Several Animal Models to Explain at the Genetic Level the Diversity of Morphological and Physiological Relevant Traits

“…Considering the potential homology between the mouse and rabbit Dilute loci, the rabbit MYO5A gene was first investigated to evaluate if its mutations could be responsible for the coat color dilution observed in a few rabbit breeds, such as Vienna Blue. Fontanesi et al [72] excluded that the rabbit MYO5A gene was involved in determining the Dilute locus in this lagomorph species. Then, the rabbit melanophilin (MLPH) gene that in mice is responsible for a similar coat color phenotype determined by the Leaden locus [73] was investigated.…”

Coat colour inheritance in American mink (Neovison vison): Pedigree analysis

“…The action of the Myo5a gene has been quite well understood in other mammalian species, such as dogs, cats, mice, and rabbits [Searle 1968, Desnos et al 2007, Fontanesi et al 2012]. Some of these species have variations with brightened coat colour phenotypically similar to colours of mink, for example Russian blue in cats or Isabella in dogs -hence the decision to include the d allele in the genotypes.…”

Association of Melanophilin (MLPH) gene polymorphism with coat colour in Rex rabbits

“…In humans, mutations in the MLPH gene have been shown to cause Griscelli syndrome type III, which is an autosomal recessive disorder characterised by pigment dilution of the skin and hair (OMIM 609227) (Ménasché et al, 2003). Fontanesi et al first investigated the rabbit homologous gene of the mouse dilute locus and excluded MYO5A as the determinant of the dilute locus in rabbit (Fontanesi et al, 2012). After that, they found that a frameshift mutation in the MLPH gene (exon 5) causes the dilute coat colour in different rabbit (Oryctolagus cuniculus) breeds (Fontanesi et al, 2014).…”