Rapid Evolution of Tandemly Duplicated Genes in Legume Genomes

The tandem duplication as small-scale duplication has been reported to belong to the gene ontology categories of response to stress or secondary metabolism suggesting that those genes might be under on-going evolution processes to keep being adapted in given environments. Legume species have special environmental interaction with symbiotic bacteria to fix nitrogen which is agriculturally important feature for nitrogen supplement, so we assumed that parts of tandemly duplicated genes in two legume genome, Glycine max and Medicago truncatula, evolved to build up symbiosis pathway. We retrieved the tandemly duplicated genes in those genomes using self-megablast of coding sequences. Gene ontology analysis was done to understand the functions of tandemly duplicated genes showing that majority of those genes belong to the GO categories of cellular process, metabolic process and response to stimulus. Ks values among the tandemly duplicated gene cluster were also analyzed to figure out the activity of the tandem duplication process to observe the gene contents with recent tandem duplication. Moreover, we took advantage of several publically available transcriptome data of soybean regarding nodulations and found differentially expressed genes in tandemly duplicated gene set. Those genes clusters might have a role on the interaction between plant and symbiotic bacteria.