Genetic analysis of melanocortin 1 receptor gene in endangered Greek sheep breeds

In sheep, the MC1R gene is located on chromosome 14 (OAR14) and has three main alleles (E+, ED, and e), which are defined by three mutations in the coding region and associated with variation in coat color. Here we report a first attempt to assess the genetic polymorphism of the MC1R gene in Greek sheep breeds. Blood samples were obtained from 198 animals, from the following 11 local Greek sheep breeds: Frizarta, Boutsiko, Argos, Kymi, Zakynthos, Chios, Florina, Sarakatsaniko, Thraki, Karagouniko, Katsika. Four different alleles with four single nucleotide polymorphisms (SNPs) were detected. Three mutations have already been reported: one synonymous mutation (c.735 C > T, p.245 lle > Ile) and two nonsynonymous mutations previously associated with black coat color (c.218 T > A, p.73 Met > Lys. c.361 G > A, p.121 Asp > Asn). One nonsynonymous mutation, with a frequency of 2%, has never been reported (c.789 T > C, p.263 Leu > Pro) and it was present only in Florina and Thrall breeds, of Zackel and Tsigai origin respectively and could be a remnant polymorphism, originating from common ancestors and maintained accidentally in both breeds. More detailed studies are needed to elucidate if the allele contributes to the occurrence of black spots around the head, present in both breeds or to any other common phenotypic character. In any case, as the genetic diversity of local breeds quickly deteriorates, their genetic differentiation needs to be conserved imperatively as it could serve to add diversity to highly inbred pure breeds.