In other species: horse , taurine cattle , meadow voles , red fox , pig , sheep , domestic cat , rabbit , dog , gray wolf , coyote , goat , Eurasian water mole , Northern mole vole , North American deer mouse , alpaca , leopard , Asiatic golden cat , leopard cat , impala , Colocolo , Kodkod , Arabian camel , Mongolian gerbil , domestic guinea pig , Western roe deer , llama , oldfield mouse

Categories: Pigmentation phene

Possibly relevant human trait(s) and/or gene(s)s (MIM numbers): 611742 (trait) , 600201 (gene)

Links to MONDO diseases: No links.

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal recessive

Considered a defect: no

Key variant known: yes

Year key variant first reported: 2015

Cross-species summary: This locus, ASIP, encodes the agouti signalling protein, a peptide antagonist of the melanocyte-stimulating hormone receptor (MC1R), which is the product of the extension locus. As explained by Schneider et al. (PLoS Genet 10(2): e1004892; 2015), "The most common causes of melanism (black coat) mutations are gain-of-function alterations in MC1R, or loss-of function alterations in ASIP, which encodes Agouti signaling protein, a paracrine signaling molecule that inhibits MC1R signaling".

Species-specific description: Sun et al. (2017): "Donkeys have various coat colors with two major patterns: no light points (NLP) and light points (LP). . . . Animals with the LP pattern have black or grey to spotting and black or grey with cream to grey-white hair around the muzzle and eyes."

Molecular basis: Abitbol et al. (2015): a likely causal variant for the no light points (NLP) phenotype is c.349T>C; p.Cys117Arg

Prevalence: Sun et al. (2017): "All 20 solid-black Dezhou donkeys had the CC genotype, which indicates that the ASIP c.349T>C variant distinguishes between solid-black (genotype CC) and non-black (genotype TT and TC) donkeys, at least in the Dezhou donkeys and most likely also in other breeds. Our results will facilitate the selection of the solid-black coat color in donkeys."

From a survey of 283 donkeys, Yu et al. (2020) reported "Donkeys homozygous for the ASIP [c.349]T‐allele all have light points, which are missing in all homozygous C‐allele genotype at c.349T>C (CC) animals . . . However, 27.8% of the NLP [no light points] donkeys are heterozygous, which has not been found previously. . . . The variable phenotypes of ASIP heterozygotes and of ASIP TT homozygotes indicate the involvement of one or more other genes that so far have not been identified."

Associated gene: