Genonle Evolution Studied Through Protein Structure

In 1859, Charles Darwin published The Origin o/Species, a seminal work that defined the beginning of evolutionary biology (Darwin. 1859). However, Darwin's studies were con­ strained by phenotype-those characteristics of organisms that could be visibly observed, both in living and in the fossil record. The discovery of DNA as the method by which genetic information was transferred (Avery et al., 1944) and the subsequent ability to sequence DNA (Sanger and Coulson, 1975; Sanger et aI., 1977). RNA (Sanger, and later proteins (Biemann, 1992) enabled evolution to be studied at the molecular level. Advances in our evolutionary understanding came from an increase in the number of gene sequences and improved computational techniques and computational infrastructure. Combining molecular observations with observations at the species levelled to innovations such as molecular clocks (Zuckerkandl and Pauling, 1962), principles of parsimony, and to an understanding of allele frequencies based on the processes ofmutation. genetic drift, gene flow, and natural selection. Such methods have largely focused on finding similarities and differences in the DNA or protein sequences of selected organisms. As organisms evolve, events such as point