Question

Adaptive evolution depends upon mutations to generate genetic variation. Yet, evolutionary theory predicts that mutations are random and yet most mutations are harmful (deleterious) or have no effect (neutral). Explain this apparent paradox drawing upon your knowledge of genomic elements and gene structures. Does changing the mutation rate (for example, by exposure to mutagens) alter these expectations? Defend your argument.

Answer 1

Evolutionary theory is dependent on natural selection which propagates adaptive evolution through occurrence of beneficial traits in a population thereby allowing greater survival rate of individuals possessing greater evolutionary fitness. An evolutionary fit species will contribute positively to the gene pool of the next generation. Such beneficiary mutation not only adds to gene pool but also leads to diversification for the benefit of individuals.

While harmful mutations disrupt the normal functioning of an organism and may deteriorate the chances of survival of an individual. This leads to reduction of gene pool in long run.

Thus mutation causing betterment and diversification oriented to better survival are continous and good for survival and genetic variation of an individuals. Harmful mutations are deleterious.