Department of Biochemistry and Biophysics and Stockholm Bioinformatics Center, Stockholm University, 10691 Stockholm, Sweden. liberles@sbc.su.se
As more gene and genomic sequences from an increasing assortment of species become available, new pictures of evolution are emerging. Improved methods can pinpoint where positive and negative selection act in individual codons in specific genes on specific branches of phylogenetic trees. Positive selection appears to be important in the interaction between genotype, protein structure, function, and organismal phenotype.