SWAKK: a web server for detecting positive selection in proteins using a sliding window substitution rate analysis

We present a bioinformatic web server ( SWAKK) for detecting amino acid sites or regions of a protein under positive selection. It estimates the ratio of non-synonymous to synonymous substitution rates (K-A/K-S) between a pair of protein-coding DNA sequences, by sliding a 3D window, or sphere, across one reference structure. The program displays the results on the 3D protein structure. In addition, for comparison or when a reference structure is unavailable, the server can also perform a sliding window analysis on the primary sequence. The SWAKK web server is available at http://oxytricha.princeton.edu/SWAKK/.