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OMIA 001806-9615 : Coat colour, saddle tan vs black-and-tan in Canis lupus familiaris

Possibly relevant human trait(s) and/or gene(s) (MIM number): 614663

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal Recessive

Considered a defect: no

Key variant known: yes

Year key variant first reported: 2013

Inheritance: Dreger et al. (2013) provided data that enabled them to conclude that "it appeared that the black-and-tan pattern is recessive to saddle tan".

Mapping: Using genotype data from the Affymetrix Canine Array v2.0 100K SNP chip, Dreger et al. (2013) conducted a GWAS on "130 black-and-tan and saddle tan cases and 596 non-pattern controls" and another GWAS on "33 saddle tan cases and 97 black-and-tan controls". The first GWAS confirmed the ASIP locus on chromosome CFA24 as being responsible for the black-and-tan and saddle tan phenotypes (see OMIA 000201-9615). The second GWAS revealed that "the saddle tan phenotype maps specifically to a region separate from and upstream of ASIP".

Molecular basis: By sequencing the most likely candidate gene in the candidate region upstream from ASIP (see Mapping section above), Dreger et al. (2013) discovered that the black-and-tan/saddle tan polymorphism is due to "a 16-bp duplication (g.1875_1890dupCCCCAGGTCAGAGTTT) in an intron of hnRNP associated with lethal yellow (RALY), which segregates with the black-and-tan phenotype in a group of 99 saddle tan and black-and-tan Basset Hounds and Pembroke Welsh Corgis. In these breeds, all dogs with the saddle tan phenotype had RALY genotypes of +/+ or +/dup, whereas dogs with the black-and-tan phenotype were homozygous for the duplication. The presence of an a y/_ fawn or e/e red genotype is epistatic to the +/_ saddle tan genotype. Genotypes from 10 wolves and 1 coyote indicated that the saddle tan (+) allele is the ancestral allele, suggesting that black-and-tan is a modification of saddle tan." However, the authors also reported that "An additional 95 dogs from breeds that never have the saddle tan phenotype have all three of the possible RALY genotypes", indicating that there is more to this story than has been revealed to date.

Breeds: Basset Hound, Pembroke Welsh Corgi.

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
RALY RALY heterogeneous nuclear ribonucleoprotein Canis lupus familiaris 24 NC_006606.3 (23173209..23258712) RALY Homologene, Ensembl, NCBI gene

Variants

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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
Coat colour, black-and-tan RALY duplication CanFam3.1 24 g.23252754_23252770dupCCCCAGGTCAGAGTTT 2013 23519866 Genomic location and details kindly provided by Professor Claire Wade in August 2018
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Reference


2013 Dreger, D.L., Parker, H.G., Ostrander, E.A., Schmutz, S.M. :
Identification of a mutation that is associated with the saddle tan and black-and-tan phenotypes in Basset Hounds and Pembroke Welsh Corgis. J Hered 104:399-406, 2013. Pubmed reference: 23519866. DOI: 10.1093/jhered/est012.

Edit History


  • Created by Frank Nicholas on 13 May 2013
  • Changed by Frank Nicholas on 13 May 2013