16 May 2005
A report published by researchers from the California-based company Celera Diagnostics and Cornell University in the latest edition of Science compares equivalent chimpanzee, human and mouse genes [Clark et al. (2003) Science 302, 1960-1963]. The chimpanzee and human genomes share over 99% sequence identity, so regions of variation between these two genomes can help to identify biologically important species differences. More than 7500 chimpanzee gene sequences were aligned with the orthologous human sequences in order to identify genetic differences. These alignments were then compared with the corresponding murine sequences, in order to identify evolutionary changes that occurred since the human and chimp ancestral lineages diverged more than five million years ago.
Evolutionary genetic changes (resulting from processes of natural selection) were defined as those showing significantly more rapid alteration than would be expected from normal rates of random mutation alone; over 1500 genes were classified as showing evidence of this