Dr. Jeffrey Miller's group is interested in understanding how mutations occur in cells of bacteria and other organisms and how cells avoid mutagenesis with different strategies. He and his colleagues have extended their work to include extreme thermophiles, organisms that can grow at temperatures up to 110°C. There are many fundamental questions posed by these organisms - for instance, how they avoid excessive mutations at high temperature, and how their proteins fold correctly and remain stable at high temperature.

Miller and his colleagues have exploited the strategy of examining mutator strains, those with higher mutation rates, to detect new repair systems in bacteria and have cloned and sequenced their human homologs. For work with extreme thermophiles, the researchers have sequenced the entire genome of a microorganism from the third kingdom, Archaea, which has 2.2 million base pairs, and can grow up to 104°C. Miller is analyzing this sequence in detail and comparing it to other sequenced genomes.