GEPHE SUMMARY Print
Gephebase Gene
Entry Status
Published
GepheID
GP00001325
Main curator
Prigent
PHENOTYPIC CHANGE
Trait Category
Trait State in Taxon A
Domestic sheep - dominant white phenotype in Australian Merino breed
Trait State in Taxon B
Domestic sheep - recessive "self-color black" phenotype in Australian Merino breed
Ancestral State
Taxon A
Taxonomic Status
Taxon A
Latin Name
Common Name
sheep
Synonyms
Ovis ammon aries; Ovis orientalis aries; Ovis ovis; sheep; domestic sheep; lambs; wild sheep; Ovis aries Linnaeus, 1758
Rank
species
Lineage
Show more ... leostomi; Euteleostomi; Sarcopterygii; Dipnotetrapodomorpha; Tetrapoda; Amniota; Mammalia; Theria; Eutheria; Boreoeutheria; Laurasiatheria; Cetartiodactyla; Ruminantia; Pecora; Bovidae; Caprinae; Ovis
NCBI Taxonomy ID
is Taxon A an Infraspecies?
Yes
Taxon A Description
Domestic sheep - dominant white phenotype in Australian Merino breed
Taxon B
Latin Name
Common Name
sheep
Synonyms
Ovis ammon aries; Ovis orientalis aries; Ovis ovis; sheep; domestic sheep; lambs; wild sheep; Ovis aries Linnaeus, 1758
Rank
species
Lineage
Show more ... leostomi; Euteleostomi; Sarcopterygii; Dipnotetrapodomorpha; Tetrapoda; Amniota; Mammalia; Theria; Eutheria; Boreoeutheria; Laurasiatheria; Cetartiodactyla; Ruminantia; Pecora; Bovidae; Caprinae; Ovis
NCBI Taxonomy ID
is Taxon B an Infraspecies?
Yes
Taxon B Description
Domestic sheep - recessive "self-color black" phenotype in Australian Merino breed
GENOTYPIC CHANGE
Presumptive Null
No
Molecular Type
Aberration Type
SNP
Molecular Details of the Mutation
unidentified promoter silencing
Experimental Evidence
Authors
Norris BJ; Whan VA
Abstract
Agouti signaling protein (ASIP) functions to regulate pigmentation in mice, while its role in many other animals and in humans has not been fully determined. In this study, we identify a 190-kb tandem duplication encompassing the ovine ASIP and AHCY coding regions and the ITCH promoter region as the genetic cause of white coat color of dominant white/tan (A(Wt)) agouti sheep. The duplication 5' breakpoint is located upstream of the ASIP coding sequence. Ubiquitous expression of a second copy of the ASIP coding sequence regulated by a duplicated copy of the nearby ITCH promoter causes the white sheep phenotype. A single copy ASIP gene with a silenced ASIP promoter occurs in recessive black sheep. In contrast, a single copy functional wild-type (A(+)) ASIP is responsible for the ancient Barbary sheep coat color phenotype. The gene duplication was facilitated by homologous recombination between two non-LTR SINE sequences flanking the duplicated segment. This is the first sheep trait attributable to gene duplication and shows nonallelic homologous recombination and gene conversion events at the ovine ASIP locus could have an important role in the evolution of sheep pigmentation.
Additional References
RELATED GEPHE
Related Haplotypes
2
COMMENTS
The mutation is recessive and probably induces a loss-of-function
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