GEPHE SUMMARY Print
Entry Status
Published
GepheID
GP00000658
Main curator
Martin
PHENOTYPIC CHANGE
Trait Category
Trait State in Taxon A
Equus caballus
Trait State in Taxon B
Equus caballus - splashed white phenotypes
Ancestral State
Taxon A
Taxonomic Status
Taxon A
Latin Name
Common Name
horse
Synonyms
Equus przewalskii f. caballus; Equus przewalskii forma caballus; horse; domestic horse; equine; Equus caballus Linnaeus, 1758
Rank
species
Lineage
Show more ... rata; Gnathostomata; Teleostomi; Euteleostomi; Sarcopterygii; Dipnotetrapodomorpha; Tetrapoda; Amniota; Mammalia; Theria; Eutheria; Boreoeutheria; Laurasiatheria; Perissodactyla; Equidae; Equus; Equus
NCBI Taxonomy ID
is Taxon A an Infraspecies?
No
Taxon B
Latin Name
Common Name
horse
Synonyms
Equus przewalskii f. caballus; Equus przewalskii forma caballus; horse; domestic horse; equine; Equus caballus Linnaeus, 1758
Rank
species
Lineage
Show more ... rata; Gnathostomata; Teleostomi; Euteleostomi; Sarcopterygii; Dipnotetrapodomorpha; Tetrapoda; Amniota; Mammalia; Theria; Eutheria; Boreoeutheria; Laurasiatheria; Perissodactyla; Equidae; Equus; Equus
NCBI Taxonomy ID
is Taxon B an Infraspecies?
Yes
Taxon B Description
Equus caballus - splashed white phenotypes
GENOTYPIC CHANGE
Generic Gene Name
Mitf
Synonyms
Wh; bw; mi; vit; BCC2; Bhlhe32; Gsfbcc2; Vitiligo; Bw; Mi; Vit
Sequence Similarities
Belongs to the MiT/TFE family.
UniProtKB
Mus musculus
GenebankID or UniProtKB
Presumptive Null
No
Molecular Type
Aberration Type
Insertion Size
10-99 bp
Molecular Details of the Mutation
11bp insertion in melanocyte-specific promoter; disrupting PAX3 binding site
Experimental Evidence
Authors
Hauswirth R; Haase B; Blatter M; Brooks SA; Burger D; Drögemüller C; Gerber V; Henke D; et al. ... show more
Abstract
During fetal development neural-crest-derived melanoblasts migrate across the entire body surface and differentiate into melanocytes, the pigment-producing cells. Alterations in this precisely regulated process can lead to white spotting patterns. White spotting patterns in horses are a complex trait with a large phenotypic variance ranging from minimal white markings up to completely white horses. The "splashed white" pattern is primarily characterized by an extremely large blaze, often accompanied by extended white markings at the distal limbs and blue eyes. Some, but not all, splashed white horses are deaf. We analyzed a Quarter Horse family segregating for the splashed white coat color. Genome-wide linkage analysis in 31 horses gave a positive LOD score of 1.6 in a region on chromosome 6 containing the PAX3 gene. However, the linkage data were not in agreement with a monogenic inheritance of a single fully penetrant mutation. We sequenced the PAX3 gene and identified a missense mutation in some, but not all, splashed white Quarter Horses. Genome-wide association analysis indicated a potential second signal near MITF. We therefore sequenced the MITF gene and found a 10 bp insertion in the melanocyte-specific promoter. The MITF promoter variant was present in some splashed white Quarter Horses from the studied family, but also in splashed white horses from other horse breeds. Finally, we identified two additional non-synonymous mutations in the MITF gene in unrelated horses with white spotting phenotypes. Thus, several independent mutations in MITF and PAX3 together with known variants in the EDNRB and KIT genes explain a large proportion of horses with the more extreme white spotting phenotypes.
Additional References
COMMENTS
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