The genetic basis of biodiversity: genomic studies of cichlid fishes

Genomic techniques allow new approaches to long-standing questions in evolutionary biology. In particular, the development of linkage maps will accelerate the identification of genes underlying adaptive traits. We discuss the application of these technologies to understanding the radiation of cichlid fishes in Lake Malawi, East Africa. We have developed a linkage map for Oreochromis niloticus and are using it to identify the genetic factors controlling adaptive differences in jaw morphology among closely related Malawi cichlids. Cloning of visual pigment genes is leading to a new understanding of the visual capabilities of these fishes. We argue that a combination of linkage mapping, transcriptome profiling and analysis of candidate genes is likely to be the most efficient approach to identifying the genetic basis of adaptive evolution.