Assessing and improving the accuracy of detecting protein adaptation with the TreeSAAP analytical software.

TreeSAAP has been used in a variety of protein studies for detecting adaptation in terms of the physicochemical properties involved in amino acid replacement. The accuracy of TreeSAAP was here tested using simulated protein-coding DNA data. A sampling of 1402 simulated amino acid replacements resulted in a default accuracy of 81.1%, with most properties exhibiting >90% accuracy. More than half of the false-positive results were traced to just 11 of the 180 possible single-step amino acid exchanges. Overall accuracy increased as the number of magnitude partitions used in the analysis decreased. Sliding window size did not significantly affect accuracy.