The aim of this project is to understand the biodiversity on Earth from various view points encompassing from molecular level to ecological level. Evolutionary view is indispensable in the integrative understanding of the biodiversity, and the methods for inferring molecular phylogeny are essentially important. In this project, we are developing models of nucleotide substitutions during evolution and methods for phylogenetic inference based on maximum likelihood. In developing the statistical methods, we simultaneously try to solve real problems of biological importance.
The biological problems we are working on include evolution of vertebrates such as mammals and birds, evolution of land plants, and the biodiversity of Malagasy fauna. Madagascar has been isolated from any continents for a long geological time, and has developed a unique fauna with high level of combined species richness and endemism. In Madagascar, we are working on the biogeographic problems of tenrecs and lemurs (mammals) and baobabs (plants). Spiny tenrec is morphologically very similar to hedgehog (Fig. 2), and had long been classified in Insectivora together with hedgehogs, moles, and shrews, but molecular phylogenetic analyses clarified that tenrecs belong to Afrotheria which includes elephants, hyraxes, and aardvarks, and that the similarity between spiny tenrec and hedgehog is due to convergent evolution. Estimation of the time-scale of lemurs and baobabs gave important clues in clarifying the origin of these groups of organisms in Madagascar. We are also analyzing the problems on the phylogenetic position of Yangtze river dolphin (Lipotes vexillifer; Fig. 1) in the evolution of whales.

Members
Masami HASEGAWA, Jun ADACHI, Ying CAO, Masato NIKAIDO,
Yuriko NISHIMOTO, Atsushi MATSUI, Hideya MITSUI,
Takahiro YONEZAWA, Yumie MURATA, Jun-ichi OHNAMI�j