Of mice and mitochondria

Mitochondrial DNA mutates at a faster rate than nuclear genomic sequences and may provide a mechanism for organisms to adapt rapidly to a changing environment. Mitochondrial proteins interact with gene products encoded by the "host" nucleus to carry out oxidative phosphorylation, and selection pressure may cause these interactions to work at maximum efficiency under different conditions. Comparative analysis of mitochondrial DNA sequences has been used to discover phylogenetic and phylogeographic patterns in a number of organisms. In the May 22 Nature, Oliver Pergams and colleagues at the University of Illinois at Chicago use these techniques to detect possible variations in the conditions in which an organism is living (Nature, 423:397, May 22, 2003).

Pergams et al. obtained specimens of skin of the white-footed mouse, Peromyscus leucopus, from museums worldwide. They obtained 61 samples originally collected from five different areas in Chicago and compared a 340bp polymorphic region...