For some time I’ve puzzled over how mutations arose essentially simultaneously (i.e. within a short time span) to generate new hominid species, especially homo sapiens. (Please, dear reader, don’t refer me to elementary texts or courses on evolution–they don’t answer this question satisfactorily. In this I’m not alone–better minds than mine–Stuart Kauffman, Thomas Nagel, Ilya Prigogine–to name just a few, are not satisfied with the conventional neo-Darwinian model for evolution
Greg Bear, the author of "Darwin Radio", gives a plausible (if unproven) answer to this question. Human ERV (Endogenous RetroVirus) cause an epidemic: the HERV is transmitted by men to women with whom they have a “steady” sexual relation; the virus causes spontaneous abortions, but the aborted fetus carries an egg that produces a second pregnancy. The child born in this second pregnancy has unusual and different capabilities, including parallel processing in the brain, pherenomes and facial pigmentation changes to convey subtleties in communication–in short a new species.
That such an evolutionary change has occured before is shown in the novel by the discovery of a prehistoric couple preserved in a glacial cave; the male and female are some 15000 years old, and apparently Neanderthals–but there is also a baby, which is apparently Homo Sapiens. The discovery in this prehistoric couple of the HERV that occurs in the modern epidemic suggests that this was the cause of change to Homo Sapiens from early forms. (In this Bear make a paleontological error; Neanderthals and Homo Sapiens were both present over a fairly long time period, and various human races contain up to 3% of Neanderthal genes.)
So, Bear’s suggestion is that somehow, a concerted epidemic carried by ERV, is the mechanism by which jumps to new species occurs. An important question (not answered in the novel) is “who sends the signal for Darwin’s Radio to sound?”, i.e. what causes this epidemic to occur over a limited time span?
How would one criticize Bear’s speculative mechanism? What might be alternative mechanisms for simultaneous mutation in many individuals over a short time period?
And I’ll be the first to admit my scientific expertise is not in molecular biology.
*Molecular biology terms will be explained with links to appropriate websites.