Here’s a quote from a paper I ran into a few months back. I’ve been meaning to post it. I certainly have Liz Liddle in mind as I do so.
I would ask that you resist your urge to ‘google’ the quote, and simply ask yourself the question: when was this paper published. Then have a gander. It’s a paper by Hampton L. Carson. From the abstract:
The experiments reported in this paper are designed to test the effect of raising
the genetic variance in experimental populations in a different way, namely, by
the use of large doses of X-rays delivered frequently to all the adults in the popu-
lation. The populations were thus closed ones in which the mutation rate was
artificially maintained at a very high level. Under these conditions, the experi-
mental populations represent a sensitive system for the detection of the effects of
newly induced genes that cause increase in fitness, whether these effects may be
manifested in the heterozygous condition, the homozygous condition, or both.
The results clearly show that there is no sustained increase in fitness despite an
increased genetic variance as indicated by an observed increase in genetic load.
There is thus no evidence for single-gene heterosis or for the induction of new
genes having a favorable effect on any of the fitness characters.
Liz Liddle seems convinced that neutral drift/draft is sufficient to provide all the genetic variance needed for evlution. And here’s an experiment where they raised the mutation rate to its limit, and, still, no overall gain in fitness (These were Drosophila populations). RM+NS just doesn’t have enough fire-power. Actually, it’s not even close to having enough fire-power to explain the progression of life-forms. Why wasn’t Darwinism dead a long time ago? Here’s the link.