Gene Rearrangements, a Force for Evolutionary Change; DNA Sequence Arrangements,a Source of Genetic Constancy

摘要

A paradox posed by many biological systems is their tendency to resist geneticchange coupled with their potential for rapid diversification. Unity underlying such processes was suggested years ago by I.C. Gunsalus, who recognized that the immune system, the mind, detoxifying systems in the liver and microbial catabolic pathways are representatives of what he termed the biology of anticipation. In all of these systems, a novel challenge elicits a complex and far from random response. The response is stored in a memory that may be called upon in response to renewed challenge. Bacterial catabolic pathways illustrate the biology of anticipation. Their evolution demanded a complex genetic response (acquisition of a set of enzymes and regulatory genes) in response to a novel challenge (the availability of a previously unencountered growth substrate. Reprints. (jes)