Mark Mitton system



Mark Mitton system

a.

The most important improvement achieved over the unitary matrix was based on evolutionary distances. Margaret Dayhoff pioneered this approach in the 1970's. She made an extensive study of the frequencies in which amino acids substitute for each other during evolution. The studies involved carefully aligning all of the proteins in several families of proteins and then constructing phylogenetic trees for each family. This lead to a table of relative frequencies with which amino acids replace each other over an evolutionary period. This table and the relative frequency of occurrence of amino acids in the proteins studied ...