Comparative genomics studies across taxa provide basic understanding of genome evolution. This study focused on nuclear genes encoding mitochondrial proteins across Arabidopsis and several grass species. Two different mitochondria-related gene sets, one rice-derived and another Arabidopsis-derived, were used in our analysis. Eleven of the rice-derived genes, from a 6.85 Mb region of chromosome 10, were physically mapped using radiation hybrid (RH) approach on chromosome ID of wheat. Based on the comparative analysis of these 11 genes, genomes of wheat and maize shared more comparable pattern of conservation than wheat and rice. Additionally, rice, revealed to have perfectly conserved colinearity with Brachypodium, whereas, wheat and Brachypodium showed less preserved synteny. This was surprising since previous studies have estimated that Brachypodium was evolutionarily closer to wheat than rice when comparing their divergence times. Some rearrangements in studied regions of wheat and maize genomes may indicate a relaxation of evolutionary pressure on gene order in polyploid as compared with diploid species. Additionally, our cluster analysis on chromosome 10 of rice identified two mitochondria-related gene clusters, one containing seven and another one two genes. Analysis of Arabidopsis-derived set of 473 genes showed 14 to 16% conservation in rice, maize, Brachypodium, and wheat. Forty five genes showed to be conserved in representatives of monocots as well as in Arabidopsis which underlies the significance of their conservation for survival of plant mitochondria. Moreover, observed clustering of the mitochondria-related nuclear genes on chromosome 10 of rice indicates that the gene clustering might be one of the ways to preserve crucial genes from major rearrangements or recombination events that could compromise their function.
|Original language||English (US)|
|Number of pages||13|
|State||Published - Dec 1 2009|
- Mitochondria-related genes
- Radiation hybrid mapping