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Differences in the expression of the ASIP gene are involved in the recessive black coat colour pattern in sheep: evidence from the rare Xalda sheep breed
Author(s) -
Royo L. J.,
Álvarez I.,
Arranz J. J.,
Fernández I.,
Rodríguez A.,
PérezPardal L.,
Goyache F.
Publication year - 2008
Publication title -
animal genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.756
H-Index - 81
eISSN - 1365-2052
pISSN - 0268-9146
DOI - 10.1111/j.1365-2052.2008.01712.x
Subject(s) - biology , genotype , coat , allele , breed , genetics , gene , white (mutation) , coding region , gene expression , paleontology
Summary Here we have tested the hypothesis of association between different levels of agouti signalling peptide ( ASIP ) mRNA and the recessive black coat colour in the rare Xalda breed of sheep. To deal with this task, we first tested the possible action of both the dominant black extension allele ( E D ) and a 5‐bp deletion (X99692:c.100_104del; A del ) in the ovine ASIP coding sequence on the black coat colour pattern in 188 Xalda individuals. The E D allele was not present in the sample and only 11 individuals were homozygous for the A del ASIP allele. All Xalda individuals carrying the A del / A del genotype were phenotypically black. However, most black‐coated individuals (109 out of 120) were not homozygous for the 5‐bp deletion, thus rejecting the A del / A del genotype as the sole cause of recessive black coat colour in sheep. Differences in expression of ASIP mRNA were assessed via RT‐PCR in 14 black‐coated and 10 white‐coated Xalda individuals showing different ASIP genotypes ( A wt / A wt , A wt / A del and A del / A del ). Levels of expression in black animals were significantly ( P < 0.0001) lower than those assessed for white‐coated individuals. However, the ASIP genotype did not influence the ASIP mRNA level of expression. The consistency of these findings with those recently reported in humans is discussed, and the need to isolate the promoter region of ovine ASIP to obtain further evidence for a role of ASIP in recessive black ovine pigmentation is pointed out.