Phylogenetic and evolutionary analysis of nucleotide sequence of FASN gene

In the this research, 38 Holstein dairy cows (18 heads low production and 20 heads high-production) were selected randomly and blood samples were taken their from tail vein. DNA was extracted from whole blood with phenol-chloroform. PCR amplification of 750bp from 37 to 39 exons of FASN gene was performed using one pairs of special primers. Sequencing of the amplified region was performed by the Sanger method. Sequence data of other species was achieved and aligned by searching its genome database (NCBI). The nucleotide substitution rate of the sequences and molecular evolution of the FASN were calculated by maximum likelihood and neighbor-joining method, respectively and phylogenetic tree was constructed. Evolutionary and phylogenetic tree analysis was performed using MEGA6 and Dnasp5.1 softwares. Bioinformatics analysis results showed that the substitution percentage of purines was more than pyrimidine nucleotides. The numerical value of dN/dS in two groups of dairy cow and in comparison with that of other species were 1.16 and 1.12, respectively which indicating positive selection during evolution of this gene. Phylogenetic tree for the FASN gene in mammals shows close relationship between Buffalo and Bison, as well as Cats and Cheetahs (%98 and %57, respectively).The results show that over the years segregation and selection of new varieties, resulted in the development of new varieties, new proteins and also stabilizes their performance during the evolution and advance progress toward their performance has been purified.