Genome duplication could be one opportunity for the birth of new species. It is estimated that more than 70% plant species have experienced genome duplication in their history. However, very little is known about its molecular mechanism and the evolutionary and physiological significance. In this study, I focus on the gene expression control of allo- and auto-polyploid plant species, which have wider or different distribution and environmental tolerance compared to their parental species.
Genome duplication (polyploidization) could be one opportunity for the birth of new species, by combining either of the gene of the same species (autopolyploidization) or different species (allopolyploidization). It is estimated that more than 70% plant species have experienced genome duplication (polyploidization) in their history. There are several lines of evidence showing that polyploid speceis of plant are more adaptive for drastic environmental changes: Faucett et al (2009) showed that many angiosperm lineages have independently duplicated coincidentaly with the timing of the Cretaceous-Tertiary extinction event (65 million years ago) due to the advantage of altered gene expression leading to hybrid vigor and an increased set of genes. Polyploid species found in natural field tend to live in extreme habitat like cold arctic regions or dry habitat in Mediterranean climate. The theoretical researches for the last decades have revealed that it would be benefitial if some functional genes are duplicated (see Edger and Pires 2009 for review). In addition, high yield agricultural species tend to be polyploid. This fact suggests that genome duplication could have played a very important role in their evolutionary history of speciation or adaptation for new environments.
In spite of these facts, very little is known about the molecular mechanism to control the doubled genome, and the evolutionary and physiological significance of genome duplication. One of the main reasons is that most of polyploids are non-model species. Without any information about the genome sequence it was difficult to conduct molecular analysis, and even elucidating the parental species of allopolyploid species requires extensive effort in wild organisms.
In this study, I focus on the gene expression control of allo- and auto-polyploid plant species, which have wider or different distribution and environmental tolerance compared to their parental species. The analysis of wild species is enabled by taking advantage of two different types of 2nd generation sequencers. I hypothesize that a combination of two different sets of genes could be more adaptive for certain environment. The final goal is to give an answer to the question how polyploid species can be adaptive in such conditions. I use seven wild species (4 diploids, 2 allopolyploids and 1 autopolyploid) closely related to Arabidopsis thaliana, to exploit its genome information. The comparison of their expression patterns would reveal how two homeologs