Spetner, LM. 2004.
BH 14:43-55. CELD ID 21498
|Organic evolution in the Twenty-First century|
The consentient view of the mechanism of evolution has been that evolution proceeds by long series of small steps, in each of which the mutation is a single nucleotide substitution. Serious doubts, however, are now being expressed by molecular geneticists that long series of small, random, point mutations can be effective in evolution. Attention is instead being transferred to genetic rearrangements, which effect large genomic changes , and which do not appear to be random. These large mutations include insertions, inversions, and deletions, and they have been found in cases studied to be adaptive to the environment. How do they arise? There is as yet no satisfactory answer to this question. If these large changes are adaptive in a new environment, could they be triggered by that environment? Such an interpretation is being resisted, but it is a reasonable hypothesis. It would account for the observations. A theory to account for the observations. A theory to account for the evolution of the life is now more elusive than it was in the past.