Comparative analysis of gene conversion between duplicated regions in Brassica rapa and B. oleracea genomes

Abstract

Plant genomes contain many duplicated genes, some of which were produced by recursive polyploidizations. These duplicated genes may evolve interactively and even concertedly through homoeologous recombination. Here, we explored likely gene conversion in Brassica rapa and Brassica oleracea. By checking gene colinearity, we detected 4296 duplicated genes existing in both the species, which were produced by whole-genome triplication from their common ancestor. Incongruities of homologous gene tree topologies indicated that 8 % of these duplicated genes were converted by one another after the divergence of B. rapa and B. oleracea. These converted genes are more often from larger duplicated chromosomal blocks, indicating that illegitimate recombination is more likely to occur between larger homoeologous chromosomal regions. This research contributed to understanding genome stability and gene evolution after polyploidization.