Intraspecific Relationship of Sheep Based on Mitochondrial Cytochrome b Gene

[Objective] To preliminarily explore the intraspecific relationship of sheep based on cytochrome b(Cyt b) gene of mitochondrial DNA(mtDNA).[Method] The Cyt b gene sequences in 112 sheep individuals of two local sheep breeds were amplified by PCR.Then the amplified products were digested with EcoR Ι and analyzed by restriction fragment length polymorphism(RFLP).[Result] As many as 56 samples from Tan sheep and 56 samples from Wadi sheep were detected.The results showed that the amplified Cyt b gene in 51 individuals of Tan sheep had one EcoR Ι restriction site and no EcoR Ι restriction site in other five individuals,thus the Cyt b gene in Tan sheep showed two restriction morphs;the Cyt b gene in all 56 individuals of Wadi sheep had one EcoR Ι restriction site and showed one restriction morph.[Conclusion] The polymorphism of mitochondrial Cyt b gene in Tan sheep and Wadi sheep is poor,and the Cyt b gene in sheep breeds is very conservative.Therefore,using Cyt b gene as gene marker to study the intraspecific relationship of sheep has some limitations.