There is huge variety of microorganisms in nature. It has been known that most bacteria in nature are unculturable. The proportion of culturable bacteria are thought to be less than 1% of natural bacterial variety. Moreover, some symbiotic and pathogenic bacteria could not be cultured anymore because of extreme genome reductions, loss of a lot of genes by adapting nutrient-rich environments. Thus, unculturable bacteria would be unexplored areas, and many researches are recently focusing on unculturable bacteria.

　Recently novel methods for genome manipulation have been developed. Our group focuses on development of new techniques of genome manipulation and tries to apply them to the unculturable bacterial researches. In particular, we have attempted to clone a whole genome of an uncultured microorganism into an easily cultured microbial host, and to reveal the unknown biological functions in the uncultured majority.