Adaptive evolution drives the diversification of zinc-finger binding domains.

The human genome is estimated to contain 700 zinc-finger genes, which perform many key functions, including regulating transcription. The dramatic increase in the number of these genes as we move from yeast to C. elegans to Drosophila and to humans, as well as the clustered organization of these genes in humans, suggests that gene duplication has played an important role in expanding this family of genes. Using likelihood methods developed by Yang and parsimony methods introduced by Suzuki and Gojobori, we have investigated four clusters of zinc-finger genes on human chromosome 19 and found evidence that positive selection was involved in diversifying the family of zinc-finger binding motifs.