Elucidation of the molecular mechanisms of speciation - Cichlid Group - |
Speciation is considered to be the driving force for biodiversity during evolution. There are several mechanistic models for speciation, but the genes that participate in speciation have not been identified. This research group uses the diverse species of  cichlid fishes in the Great Lakes of East Africa as a model to study speciation. We want to identify genes that participated in the speciation of these fishes and apply this knowledge to the molecular mechanism of speciation. |
Inference of phylogenetic relationships based on retroposon insertions - Phylogeny Group - |
SINEs are very similar to retroposons. We noted that SINEs might be used as powerful synapomorphies (derived characteristics that are shared between taxa) in reconstructing phylogenetic trees based on SINE insertion events. SINE insertion analysis yields reliable phylogenetic relationships without the statistical error that usually accompanies other standard nucleotide sequence analysis. To date, we have used SINE insertion analysis to shed light on phylogenetic relationships among various mammals (whales, river dolphins, even-toed ungulates, and others) and fishes (salmons and cichlids). |
Elucidation of the mechanism of retrotransposition - Mechanism Group - |
Eukaryotic genomes contain a variety of retroposons. Retroposons are transposable elements that replicate via a "copy and paste" mechanism. Specifically, retroposon RNA is reverse transcribed into cDNA that is subsequently integrated into the genome at a new location. This unique amplification mechanism is termed retrotransposition. In addition, retroposons comprise a significant portion of eukaryotic genomes. For instance, retroposons occupy more than 30% of the human genome. Our retrotransposition group is investigating the mechanism by which retroposon amplification occurs, and is also working to elucidate the contribution of retroposons to the evolution of eukaryotic genomes. |
 Exapted retroposons contributed to mammalian brain evolution - Brain Group - |
Molecular mechanism of mammalian brain evolution has not been elucidated yet. We have demonstrated that retroposons have acquired a function of mammalian-specific enhancer and drive the expression of developmental genes in mammalian brain. In this group, analyzes detailed functions of enhancers are analyzed in detail. We also aim to identify other retroposons involved in brain evolution. |
