GEPHE SUMMARY
Gephebase Gene
Entry Status
Published
GepheID
GP00001324
Main curator
Prigent
PHENOTYPIC CHANGE
Trait Category
Trait State in Taxon A
Domestic sheep - ancient breed "Barbary" with wild-type pale belly phenotype
Trait State in Taxon B
Domestic sheep - Romanov and Texel breeds with dominant white allele
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 - ancient breed "Barbary" with wild-type pale belly phenotype
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 - Romanov and Texel breeds with dominant white allele
GENOTYPIC CHANGE
Presumptive Null
No
Molecular Type
Aberration Type
Insertion Size
100-1000 kb
Molecular Details of the Mutation
~190kb gene duplication causing dominant white phenotype. Duplication was facilitated by homologous recombination between two non-LTR SINE sequences flanking the duplicated segment ; possible involvement of gene conversion.
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.
RELATED GEPHE
Related Haplotypes
2
COMMENTS
Dominance : dominant allele = duplication https://omia.org/OMIA000201/9940/
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