Branching out

摘要

Seven years after the publication of the first microbial genome sequence―that of Haemophilus influenzae―the roster of microbial genomes has topped 100. Despite early fears that whole-genome sequencing might be economically justified only for human pathogens, this list represents a gratifyingly broad range of microbial phenotypes―soil bacteria and photosynth-esizers, thermophiles and halophiles, animal and plant pathogens, and more. At least 12 prokaryotic phyla are represented, as are a few eukaryotes―enough to allow a meaningful examination of the Tree of (microbial) Life.