Molecular, Evolution and Stratification Study of the Heat Shock Protein 70 (Hsp70) Genes Family in Cattle

Heat shock proteins (Hsps), are highly important due to their association with such economically important traits in animals as resistance to temperature shock and mastitis. In the current study, to get a comprehensive information on molecular structure and evolution of the Hsp70s, and the available Hsp70 sequences of the cattle and other animals taken from NCBI and aligned together. Then, nucleotide substitution rate of the sequences and molecular evolution of the gene family were calculated by maximum likelihood and neighbor-joining method, respectively, and phylogenetic tree was constructed. Bioinformatic researches results identified that Hsp70 gene family are distributed across the genome and express various transcripts necessary for functions of the related traits. On the other hand, base substitution rate of the pyrimidines to pyrimidines or purines is much more than that of in purines to pyrimidines or purines in this genes family. The dN/ds ratio of the Hsp70 sequences indicated purifying selection and stability of the structures of the genes family during evolution. Phylogenetic analysis showed that Hsp70 proteins, based on mainly are divided to two clades their evolutionary relationships. Hsp70 12a and b are sisters in one clade and sequences of the other Hsp70 proteins are in second clad and divided to many branches.