POLYMORPHISM OF SOME GENES RELATED TO MEAT TRAITS IN SOME EGYPTIAN SHEEP BREEDS

Abstract

The genetic polymorphism of some genes related to meat production in three Egyptian sheep breeds (Barki, Rahmani and Osseimi) was studied. Two main techniques were used for the study; the first was the restriction fragment length polymorphism for the polymerase chain reaction products (PCR-RFLPs) for the candidate genes: Calpastatin, Insulin-like growth factor binding protein-3, Myostatin, Diacylglycerol-acyltransferase1 and the Booroola fecundity gene. The second technique was the direct sequencing for the PCR products of Calpain gene. Polymorphisms were found in the genes: Calpastatin, Myostatin and Diacylglycerol-acyltransferase1, while no polymorphism was observed in the other two genes: Insulin-like growth factor binding protein-3 and the Booroola fecundity gene. Calpastatin locus digested with MspI had two genotypes MM and MN. The highest allelic frequency was for M allele. The same locus Calpastatin digested with NcoI also exhibited two genotypes MM and MN. The NN genotype was absent with both the MspI and the NcoI enzymes in all breeds. Myostatin digested with DraI had two genotypes AB and BB. The AA genotype wasn't present, the highest allelic frequency was for allele B. Diacylglycerol-acyltransferase1 digested with II AluI showed two genotypes CC and CT. The highest allelic frequency was for allele C. The detected CT genotype might explian the moderate intramuscular fat content and muscle marbling in the Egyption sheep breeds. Each of the remaining two genes (Insulin-like growth factor binding protein-3 and the Booroola fecundity) had only one genotype, BB genotype for Insulin-like growth factor binding protein-3 digested with HaeIII and ++ genotype for the Booroola fecundity digested with AvaII enzyme, therefore they are not recommended in the selection program.