A comprehensive study of genic variation in natural populations of Drosophila melanogaster. V. Structuralfunctional constraints on protein molecules and enzymes and the levels and patterns of variation among genes

Ever since isozyme-allozyme polymorphisms were detected there has been an incessant effort to relate the amount of observed protein variation to various aspects of molecular structure and function. Structural-functional constraints can limit the amount of overall genic variation, and the observed variation can be due to neutral mutation and random genetic drift, mutation-selection balance, or balancing selection. The present analysis of …