en بیوشیمی Biochemistry <p style="text-align: justify;"><em><strong>Background:</strong></em> Stearoyl-CoA desaturase (SCD) is a key enzyme that converts saturated fatty acids (SFAs) to monounsaturated fatty acids (MUFAs) in fat biosynthesis. Despite being crucial for interpreting SCDs&rsquo; roles across species, the evolutionary relationship of SCD proteins across species has yet to be elucidated. This study aims to present this evolutionary relationship based on amino acid sequences.</p> <p style="text-align: justify;"><strong><em>Methods: </em></strong>Using Multiple Sequence Alignment (MSA) and phylogenetic construction methods, a hypothetical evolutionary relationship was generated between the stearoyl-CoA desaturase (SCD) protein sequences between 18 different species.</p> <p style="text-align: justify;"><em><strong>Results: </strong></em>SCD protein sequences from <em>Homo sapiens, Pan troglodytes </em>(chimpanzee), and <em>Pongo abelii</em> (orangutan) have the lowest genetic distances of 0.006 of the 18 species studied. <em>Capra hircus</em> (goat) and <em>Ovis aries </em>(Sheep) had the next lowest genetic distance of 0.023. These farm animals are 99.987% identical at the amino acid level.</p> <p style="text-align: justify;"><em><strong>Conclusions:</strong></em> The SCD proteins are conserved in these 18 species, and their evolutionary relationships are similar.</p> Multiple sequence alignment, Phylogenetic analysis, Stearoyl-CoA desaturase (SCD) proteins 1 6 http://rbmb.net/browse.php?a_code=A-10-1-30&slc_lang=en&sid=1 Mohammad Salmani Izadi ms_izadi87@yahoo.com 10031947532846006013 10031947532846006013 Yes Department of Animal Sciences, Faculty of Agriculture, Ferdowsi University of Mashhad, International Campus, Mashhad, Iran Abbas Ali Naserian 10031947532846006014 10031947532846006014 No Department of Animal Sciences, College of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran Mohammad Reza Nasiri 10031947532846006015 10031947532846006015 No Department of Animal Sciences, College of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran Reza Majidzadeh Heravi 10031947532846006016 10031947532846006016 No