en زیست شناسی ملکولی Molecular Biology <p style="text-align: justify;"><em><strong>Background:</strong></em> The SRY gene <em>(SRY)</em> provides instructions for making a transcription factor called the sex-determining region Y protein. The sex-determining region Y protein causes a fetus to develop as a male. In this study, SRY of 15 spices included of human, chimpanzee, dog, pig, rat, cattle, buffalo, goat, sheep, horse, zebra, frog, urial, dolphin and killer whale were used for determine of bioinformatic differences.</p> <p style="text-align: justify;"><em><strong>Methods:</strong></em> Nucleotide sequences of<em> SRY</em> were retrieved from the NCBI databank. Bioinformatic analysis of <em>SRY</em> is done by CLC Main Workbench version 5.5 and ClustalW (http:/www.ebi.ac.uk/clustalw/) and MEGA6 softwares.</p> <p style="text-align: justify;"><em><strong>Results:</strong></em> The multiple sequence alignment results indicated that <em>SRY</em> protein sequences from Orcinus orca (killer whale) and <em>Tursiopsaduncus</em> (dolphin) have least genetic distance of 0.33 in these 15 species and are 99.67% identical at the amino acid level. <em>Homosapiens</em> and <em>Pantroglodytes </em>(chimpanzee) have the next lowest genetic distance of 1.35 and are 98.65% identical at the amino acid level.</p> <p style="text-align: justify;"><em><strong>Conclusion:</strong></em> These findings indicate that the SRY proteins are conserved in the 15 species, and their evolutionary relationships are similar.</p> Bioinformatics analysis, SRY gene, Phylogeny 76 81 http://rbmb.net/browse.php?a_code=A-10-1-53&slc_lang=en&sid=1 Masoume Vakili Azghandi 10031947532846006126 10031947532846006126 No Department of Animal Sciences, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran Mohammadreza Nasiri nassiryr@um.ac.ir 10031947532846006127 10031947532846006127 Yes Department of Animal Sciences, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran Ali Shamsa 10031947532846006128 10031947532846006128 No Department of Urology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Mohsen Jalali 10031947532846006129 10031947532846006129 No Department of Urology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Mohammad Mahdi Shariati 10031947532846006130 10031947532846006130 No Department of Animal Sciences, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran