Taking >150,000 generations for flies since creation, using a per generation deleterious mutation rate of 1.2 yields >180,000 deleterious mutations in the current generation of drosophila. This is of course a naïve calculation, but it is in response to Sanford’s more naïve hypothesis, and serves as an order of magnitude constraint. Sanford has not provided any rigorous estimates for thresholds at which catastrophe takes place, nor has he detailed how that would happen at the physiological level. Why are viruses, and flies, still with us, given that even with the outlandish timeframes of YEC, these species and many more should be long extinct were GE true?
Direct estimation of per nucleotide and genomic deleterious mutation rates in Drosophila
…the divergence between taxa at neutrally evolving sites in the genome is proportional to the per nucleotide mutation rate, u, and this can be used to date speciation events by assuming a molecular clock. The overall rate of occurrence of deleterious mutations in the genome each generation ( U ) appears in theories of nucleotide divergence and polymorphism, the evolution of sex and recombination, and the evolutionary consequences of inbreeding…
Here we directly estimate u in Drosophila melanogaster by scanning 20 million bases of DNA from three sets of mutation accumulation lines by using denaturing high-performance liquid chromatography. From 37 mutation events that we detected, we obtained a mean estimate for u of 8.4 × 10-9 per generation. …By multiplying u by an estimate of the fraction of mutations that are deleterious in natural populations of Drosophila, we estimate that U is 1.2 per diploid genome.