[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Inbreeding and accelerated evolution?



I think one can be safe by saying, the larger the litters and the more frequent the "littering", the less damage from inbreeding that will occur in a bottlenecked population. (the more they muck, the better their luck!) Double lethal recessive and damaging genes are naturally selected against so large numbers tend to muffle the expression and thus, reproduction of those genes in the population soon after the bottleneck. These results are from the dilution of the gene pool by less lethal combinations present because of a large number of individuals resultant from large litters (more rolls of the dice with the present genetic material). Additionally, larger animals tend to have "smaller litters" (except egg layers perhaps) and visa versa for smaller animals. Larger animals also have a longer developmental time before minimum breeding age thus there is a generational bias toward smaller animals having more variation within an initially equal bottlenecked population. I believe that genetic drift should occur more frequently from a smaller initial population eventually leading to a punctuated equilibrium with the environment or directly to speciation depending on the selective circumstances. The "founder effect" is very relevant here. Just look at the Amish in Pennsylvania (an isolated, small population) and the resultant effects such as dwarfism and polydactyly. Certainly this held true in the distant past as well ie. Uniformitarianism.
Frank Bliss
MS Biostratigraphy
Weston, Wyoming.