Discipline: Biological Sciences
Subcategory: Cell and Molecular Biology
Lydia Gorfu - Spelman College
DNA barcoding is based on a short gene sequence and has been used in the identification process of species and discoveries in the last decade. Species delimitation using DNA barcode depends on discovery of a DNA barcode gap based on intrastrain and interstrain divergences. Defining Barcode gap enables to delimit two closely related species or morphotypes that are morphological indistinguishable. Researchers use different approaches and sets of data to calculate divergences and infer relationships for DNA barcoding purposes. In this study we explore if computation of barcode gap differs based on the amount of characters or base pairs used in the analysis. We also investigated the effects of molecular evolution models in defining barcode gaps in a scale bearing amoeba, Cochliopodium. We analyzed over 150 cytochrome oxidase I (COI) gene sequences from 9 species of cochliopdiums and analyzed our data with different number of characters using six different models. Our findings show higher intrastrain boundary of DNA barcode gap (maximum intrastrain divergence) and lower boundary (minimum interstrain divergence) is rarely affected by the number of characters analyzed or the type of models used, while higher boundary (maximum interspecies) divergence calculations is observed to differ by up to 3% when using different models. Our analysis demonstrates defining barcode gap in Cochliopodium is not affected substantially by numbers of characters and models used.
Funder Acknowledgement(s): This study is supported by the National Science Foundation, RIA Grant (1409587) to Dr. Yonas Tekle.
Faculty Advisor: Yonas I. Tekle,