The aim of the present study was to assess the association of single nucleotide polymorphisms (SNPs) of Calpain (CAPN) gene with birth weight (BW), final weight (FW) and average daily gain (ADG) in three Egyptian sheep breeds: Barki, Rahmani and Ossimi. Blood samples were collected from 108 animals representing the three breeds. DNA was isolated using salting out procedure and then the quality and quantity of DNA extracted were measured. A 190 bp of CAPN was amplified by PCR using specific primers. The allele and genotype frequencies for all the identified SNPs were calculated. The PCR products corresponding to each genotype were sequenced to identify SNPs associated with the traits in question. Two SNPs (C→T) were detected in the nucleotides 44 and 154. For each SNP, the two mentioned alleles were named C and T, respectively. The sequenced CAPN segments were subjected to nucleotide blast at NCBI, which revealed 99% identity with that reported for sheep in Genbank. The TT was the least common genotype, whereas frequencies of CT and CC genotypes were fluctuated in the three sheep breeds under study. Animal carrier TT genotype had higher BW, FW and ADG than those with CT genotype, while the lowest values were associated with CC genotype. For the three traits under study, Rahmani had the highest estimates followed by Ossimi and Barki. Males exhibited heavier BW and FW as well as higher ADG compared with females. The results generated provide preliminary indication of the functional diversity present in Barki, Rahmani and Ossimi sheep and the possibility of using this polymorphism in Egyptian sheep genetic improvement.
Keywords: Calpain; Egyptian sheep; PCR-RFLP; Polymorphism; SNP.