Principles of Protein Structure - G. Schulz 1982

Protein Evolution
Phylogeny Based on Protein Structures
Evolution of Behavior and Morphology in Comparison with Protein Evolution

Introduction/18.html">Protein Evolution is not The basis of organismal evolution. The fact that protein specialization can be used to study evolution does not imply that the evolution of organisms—which consists in the evolution of their Morphology and behavior—proceeds in parallel with protein evolution. This is illustrated by the following Examples drawn from the works of Wilson et al. [514–517].

Placental mammals have undergone a more rapid organismal evolution compared to lower vertebrates, such as the frog. However, mammalian Proteins have apparently specialized no faster than frog proteins, and frogs form an older group (150 Ma*) than placental mammals (75 Ma). Consequently, species so close in anatomy and mode of life that they could be assigned to a single frog genus (e.g., Rana) may differ in the Amino Acid Sequence of a given protein just as much as a bat differs from a whale.

Another example involves chimpanzees and humans [514]. On average, human Polypeptides are more than 99% identical to the corresponding chimpanzee polypeptides; this is consistent with the genetic distance between closely related species of different mammals. However, the anatomical and behavioral differences between humans and chimpanzees are so substantial that they are classified into different families.

Protein specialization provides a foundation for research at the organismal level. According to the currently prevailing hypothesis, the basis of organismal evolution is likely not the evolution of structural genes and their corresponding proteins, but rather the evolution of regulatory genes [517]. There is ample evidence that adaptive evolution occurs primarily As a result of Changes in the regulatory relationships among structural genes rather than through Amino Acid Substitutions in the products of these genes. In light of this hypothesis, the value of protein specialization for constructing phylogenetic trees is enhanced, since amino acid positions in a polypeptide chain are assumed to be traits independent of evolutionary jumps. Thus, The Study of protein specialization establishes a framework for a more systematic investigation of behavioral and morphological evolution; this is particularly important for taxa with a poor fossil record.