Transferrin gene polymorphisms and population genetic studies of Atlantic cod (Gadus morhua)

摘要

Objective:To detect single nucleotide polymorphisms (SNPs) in the cod transferrin gene by comparing the sequences from Norwegian (North East Atlantic Ocean) and Canadian (North West Atlantic Ocean) specimen, and to quantify the genetic variation and differentiation in East and West Atlantic cod populations. Methods:cDNA sequences between individuals of Canadian (North West Atlantic Ocean) and Norwegian (North East Atlantic Ocean) origin were aligned. Allele frequencies of theSNPs were used to discriminate the different Atlantic cod populations in West/East Atlantic Ocean, and the Baltic Sea. Results: The sequence alignment detected19SNPs, of which 18 of them resulted in amino acid changes in the transferrin protein. Nonsynonymous to synonymous site substitution ratio (dn/ds) was by far greater than 1 providing an evidence for the existence of positive selection. The West Atlantic cod populations showed high values of heterozygosity and the Baltic populations were found to be inbred. Conclusions: This study identified and indicated transferrin gene polymorphisms that can be used for population differentiations.