Selection of Marker Genes Using Whole-Genome DNA Polymorphism Analysis

Abstract

Molecular markers serve to assign individual samples to specific groups. Such markers should be easily identified and have a high discrimination power, being highly conserved within groups while showing sufficient variability between the groups that are to be distinguished. The availability of a large number of complete genomic sequences now enables the informed selection of genes as molecular markers based on the observed patterns of variability. We derived a new scoring system based on observed DNA polymorphic differences, and which uses the Bayes theorem as adapted by Wilcox. For validation, we applied this system to the problem of identifying individual species within a prokaryotic ( Vibrio) and a eukaryotic ( Diphyllobothrium) genus for validation. Top-scoring candidates genes Chromosome segregation ATPase and ATPase-subunit 6 showed better discrimination power in Vibrio and Diphyllobothrium, respectively, as compared to standard molecular markers ( recA, dnaJ and atpA for Vibrio, and 18s rRNA, ITS and COX1 for Diphyllobothrium).