OMIA 000201-9838 : Coat colour, agouti in Camelus dromedarius

In other species: horse , 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 , ass , impala , Colocolo , Kodkod , Mongolian gerbil , domestic guinea pig , Western roe deer

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

Mendelian trait/disorder: yes

Considered a defect: no

Key variant known: yes

Year key variant first reported: 2018

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".

Molecular basis: Adopting the comparative candidate gene approach, Almathen et al. (2018) sequenced the ASIP gene in "91 animals from ten Arabian camel populations, that included the four predominant coat color phenotypes observed in the dromedary (light brown, dark brown, black and white)". They identified two variants "a 1-bp deletion (23delT/T) and a SNP (25G/A) in exon 2 of ASIP" that exist as two haplotypes, namely "23delT-25A and 23T-25G". Noting that the "23delT-25A haplotype results in a frame shift mutation, which changes the amino acid sequence and introduces a premature stop codon at position 24", Almathen et al. (2018) reported that this haplotype is associated with black and dark-brown coat colour: "Animals with black and dark-brown coat colors (n = 40, Magaheem and Sofor [populations]) were homozygous for haplotype 23delT-25A, whereas all light-brown and white individuals (n = 51) were homozygous for the 23T-25G haplotype".

Alshanbari et al. (2019) "confirmed that the majority [with 4 exceptions] of black dromedaries were homozygous for . . . [the 23delT-25A] frameshift mutation in ASIP exon 2"

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
ASIP agouti signaling protein Camelus dromedarius 19 NC_044529.1 (21604597..21537069) ASIP Homologene, Ensembl, NCBI gene


By default, variants are sorted chronologically by year of publication, to provide a historical perspective. Readers can re-sort on any column by clicking on the column header. Click it again to sort in a descending order. To create a multiple-field sort, hold down Shift while clicking on the second, third etc relevant column headers.

WARNING! Inclusion of a variant in this table does not automatically mean that it should be used for DNA testing. Anyone contemplating the use of any of these variants for DNA testing should examine critically the relevant evidence (especially in breeds other than the breed in which the variant was first described). If it is decided to proceed, the location and orientation of the variant sequence should be checked very carefully.

Breed(s) Variant Phenotype Gene Allele Type of Variant Reference Sequence Chr. g. or m. c. or n. p. Verbal Description EVA ID Year Published PubMed ID(s) Acknowledgements
Black and dark-brown coat colour ASIP haplotype c.[23delT;c.25G>A] KU179868; c.[23delT;c.25G>A]. As described by Almathen et al. (2018), this haplotype comprises "a 1-bp deletion (23delT/T) and a SNP (25G/A) in exon 2 of ASIP". 2018 29893870


Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.
2019 Alshanbari, F., Castaneda, C., Juras, R., Hillhouse, A., Mendoza, M.N., Gutiérrez, G.A., Ponce de León, F.A., Raudsepp, T. :
Comparative FISH-Mapping of <i>MC1R</i>, <i>ASIP</i>, and <i>TYRP1</i> in New and Old World Camelids and Association Analysis With Coat Color Phenotypes in the Dromedary (<i>Camelus dromedarius</i>). Front Genet 10:340, 2019. Pubmed reference: 31040864. DOI: 10.3389/fgene.2019.00340.
2018 Almathen, F., Elbir, H., Bahbahani, H., Mwacharo, J., Hanotte, O., Almathen, F., Elbir, H., Bahbahani, H., Mwacharo, J., Hanotte, O. :
Polymorphisms in MC1R and ASIP Genes are Associated with Coat Color Variation in the Arabian Camel. J Hered 109:700-706, 2018. Pubmed reference: 29893870. DOI: 10.1093/jhered/esy024.

Edit History

  • Created by Frank Nicholas on 28 Aug 2018
  • Changed by Frank Nicholas on 28 Aug 2018
  • Changed by Frank Nicholas on 05 Jun 2019