Fay and Chung-I Wu. The tests employed in the article were developed in order to aid the detection of molecular level positive selection and will help determine how viable the neutral theory is in addition to the frequency of adaptive situations. The article talks about two methods of approaching testing direct and indirect. Using the direct approach compares amino acid changes to synonymous changes while the indirect approach detects natural selection based on a skew in the frequency distribution of neutral variation linked to a site that was under