Use of principal component analysis in interpretation of deoxyribonucleic acid relatedness

Abstract

Principal component analysis (PCA) of published DNA-relatedness data showed the usefulness of this method in displaying relationships among closely related bacteria. Very similar ordinations were obtained when relative binding ratios (RBR) at 60°C or 75°C or ΔTm values were used to form the data matrix. A curvilinear relationship and a (quasi) linear relationship were found, respectively, between 75°C and 60°C RBR and ΔTm and 60°C RBR. These statistical relationships explain the similarity of PCA results using either measurement (60°C RBR, 75°C RBR, or ΔTm). Use of PCA is suggested to delineate groups within a complex set of DNA-relatedness data. The level of ΔTm within groups and between groups should help decide whether these groups are genospecies.