In other species: domestic yak

Categories: Pigmentation phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 172800 (trait) , 164920 (gene)

Mendelian trait/disorder: yes

Disease-related: no

Key variant known: yes

Year key variant first reported: 2011

Species-specific name: Color-sided

Molecular basis: As reported by Pennisi (2011), at the Biology of Genomes meeting at Cold Spring Harbor in May 2011, Durkin (2011) presented a poster reporting that the dorsal white stripe in cattle (called "colour-sided"), which maps to chromosome BTA29, appears to be due to the insertion of a duplicated 480kb fragment of DNA from BTA6 that includes the KIT gene but not all its regulators. The stripe appears to result from the at-least-partially unregulated expression of the translocated KIT. Interestingly, the gene order in the translocated segment on BTA29 is different from the gene order on BTA6, consistent with the duplicated region forming a loop which broke at a different location before being inserted in BTA29. Durkin (2011) also reported evidence that copies of the translocated fragment had escaped from BTA29, formed loops, and then were inserted alongside the original fragment on BTA6. This is the first report of such a phenomenon. Georges (2012) reported further on this phenomenon. A full account is provided by Durkin et al. (2012) who summarised the results as "colour sidedness is determined by a first allele on chromosome 29 (Cs(29)), which results from the translocation of a 492-kilobase chromosome 6 segment encompassing KIT to chromosome 29, and a second allele on chromosome 6 (Cs(6)), derived from the first by repatriation of fused 575-kilobase chromosome 6 and 29 sequences to the KIT locus. We provide evidence that both translocation events involved circular intermediates. This is the first example, to our knowledge, of a phenotype determined by homologous yet non-syntenic alleles that result from a novel copy-number-variant-generating mechanism." The same unusual mutation [called Cs(29)] was observed by Brenig et al. (2013) in two other breeds: "Homozygous (Cs(29) /Cs(29) ) White Galloway cattle and White Park cattle exhibit the [white] mismarked phenotype, whereas heterozygous (Cs(29) /[wild-type]wt(29) ) [white] individuals are either well or strongly marked. In contrast, fully black individuals are characterised by [homozygosity for] the wild-type chromosome 29." Medugorac et al. (2017) provided evidence that the colour-sided variant has been introgressed from Mongolian Turano cattle into Mongolian yaks, with which they have been herded form more than 1,500 years, enabling the backcrossing of female yak-cattle hybrids to male yaks. Artesi et al. (2020) discovered that the KIT^PINZ variant reported by Kuttel et al. (2019) as being causative for a form of colour-sidedness in Pinzgauer cattle (see OMIA 001737-9913) is also responsible for the same phenotype in Gloucester cattle.

Breeds: Belgian Blue (Cattle) (VBO_0000139), Berrenda en Negro, Spain (Cattle) (VBO_0004704), Brown Swiss (Cattle) (VBO_0000166), Cikasto govedo, Slovenia (Cattle) (VBO_0005270), Evolèner, Switzerland (Cattle) (VBO_0004498), Galloway (Cattle) (VBO_0000207), Gloucester, United Kingdom of Great Britain and Northern Ireland (Cattle) (VBO_0002964), Herens (Cattle) (VBO_0000233), Pinzgau (Cattle) (VBO_0000334), Tux-Zillertaler, Austria (Cattle) (VBO_0004409), White Park, United Kingdom of Great Britain and Northern Ireland (Cattle) (VBO_0004345).
Breeds in which the phene has been documented. (If a likely causal variant has been documented for the phene, see the variant table breeds in which the variant has been reported).

Associated gene: