Using whole genome comparison to detect sequence similarities between plants and microbes

Abstract

With an increasing amount of whole genome sequence data becoming available on a daily basis we have an opportunity to study the interactions and dynamics of different organisms on a whole genome level. In the past, reports of horizontal gene transfer have focused mainly on the identification of single genes that show distorted phylogenetic profiles to that of the organism it was isolated from. This study firstly did whole genome comparisons between the rice nuclear and plastid genomes to determine the level and dynamics gene transfer and insertion of the chloroplast ad mitochondrial genomes into that of the nuclear genome of rice. Secondly, it looked to identify sequence similarities between the rice genome and microbial genomes by performing whole genome comparisons between the rice genome and that of several microbial genomes. These sequences were analyzed further to identify possible instances of horizontal transfer of DNA from microbes to the rice genome. Using this approach, this study reports several fragments in the rice genome with significant sequence similarity to that of microbial DNA fragments. This study also provides evidence supporting horizontal transfer of several of these fragments. This study provides valuable information regarding intra- as well as inter-genome DNA transfer dynamics.Thesis (PhD)--University of Pretoria, 2009.Plant Scienceunrestricte