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Nature. 2012 Feb 1;482(7383):81-4.
Serial translocation by means of circular interme-
diates underlies colour sidedness in cattle.
Durkin K, Coppieters W, Drögemüller C, Ahariz N, Cambisano N, Druet T, Fasquelle C, Haile A,
Horin P, Huang L, Kamatani Y, Karim L, Lathrop M, Moser S, Oldenbroek K, Rieder S, Sartelet A,
Sölkner J, Stålhammar H, Zelenika D, Zhang Z, Leeb T, Georges M, Charlier C.
Abstract
Colour sidedness is a dominantly inherited phenotype of cattle characterized by the polariza-
tion of pigmented sectors on the fanks, snout and ear tips. It is also referred to as ‘lineback’ or
‘witrik’ (which means white back), as colour-sided animals typically display a white band along
their spine. Colour sidedness is documented at least since the Middle Ages and is presently
segregating in several cattle breeds around the globe, including in Belgian blue and brown
Swiss. Here we report that colour sidedness is determined by a frst 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 frst by repatriation of fused 575-kilobase chromosome 6 and 29 sequences to the
KIT locus. We provide evidence that both translocation events involved circular interme-
diates. This is the frst example, to our knowledge, of a phenotype determined by homologous
yet non-syntenic alleles that result from a novel copy-number-variant-generating mechanism.
Demonstration by FISH of the
translocation of a KIT-encom-
passing chr6 segment onto
chr29 in a heterozygous (Cs/+)
colour-sided Belgian blue ani-
mal (picture).
The zoomed image shows over-
lapping red (chr29 probe) and
green signals (chr6 probe) on
one of the chr29 homologues
revealing the translocation of
a chr6 fragment on chr29.
Demonstration by FISH of
the translocation of a chr29
segment onto chr6 in a hete-
rozygous (Cs/+) colour-sided
brown Swiss animal (picture).
The zoomed image shows
overlapping red (chr29 probe)
and green signals (chr6 probe)
on one of the chr6 homologues
revealing the translocation of
a chr29 fragment on chr6.
Model for the generation of
the colour-sided Cs29 and Cs6
alleles by serial translocation
via circular shuttling interme-
diates.