Selfish Genomic Elements and Sex: Differences in Repetitive DNA Content in the Genomes of Parthenogenetic and Nonparthenogenetic Insect Species

Abstract

Repetitive portions of DNA (specifically transposable elements) often correspond to regions of high frequency k-mers in the k-mer profile of a species’ genome. This thesis uses a databse-free based approach to characterize the k-mer profiles and quantify the amount of repetitive DNA in the genomes of closely related insects that reproduce either sexually or via parthenogenesis. With rates of transmission of genetic material between individuals being directly related to an organism’s mode of reproduction, it is hypothesized that the genomes of nonparthenogenetic/ sexuallyreproducing species will have higher amounts of repetitive DNA. The results demonstrate – that based on the species sampled in this analysis – nonparthenogenetic species have both larger haploid genome sizes and higher amounts of repetitive DNA. These results are based on correlations between genome haploid length and genome repeat length and the predictive ability of genome repeat length to classify a species’ mode of reproduction. Additionally, there are statistically significant differences between the relative frequencies of the k-mer distributions of both modes of reproduction that show that, even relative to genome size, nonparthenogentic species also have higher amounts of repetitive DNA – as the percentage of k-mers at higher coverage is greater for these species.