Steps in a phenetic analysis
a. Select the organisms under study. Taxa are called OTUs (Operational Taxonomic Units).
b. Choose the characters that will be scored for each OTU.
c. Construct an OTU by character matrix.
d. Use some mathematical formula to describe the degree of similarity or distance between each pariwise comparison of OTUs. For example, the Simple Matching Coefficient (S) is:
S = # matches between two OTUs X 100 [matches = 1, 1 and 0,0]
Total # of characters
e. Construct another matrix that gives all pairwise S values
f. Use a clustering technique (more on this below) to produce a dendrogram. A commonly used one is UPGMA
(Unweighted Pair Group Method with Arithmetic Averaging).