rationalskepticism.org

BooBoo wrote:

Shrunk wrote:
That was already known long before Behe made the claim, as shown by the references in Larry Moran's blog post. And Behe's argument is based on the odds of those two mutations occurring simultaneously in the same individual. He's strawmanning his opponents if he's claiming that they had argued that chloroquine resistance only required one mutation, which is absurd.

Behe's critics have long argued that chloroquine resistance could have evolved one mutation at a time, cumulatively. Unfortunately for them it turns out that it requires two mutations to both be present for even rudimentary transport activity to be possible. Natural selection works among individuals, so Behe is right to suppose that a simultaneous mutation is likely necessary, allowing for the less likely scenario of horizontal gene transfer.

Not exactly - anything non-lethal is still likely to persist; with many tumour suppressor genes you need both copies to be inactivated in a lineage for malignant transformation to happen - often you lose one copy and then you lose the other in a second hit because the first hit persists.

Another example is retinoblastoma - needs two hits, and people who get familial retinoblastoma are born with one hit, and then another hit takes place - nowhere is there a requirement for two simultaneous hits (note that one functional copy still blocks malignant transformation, and transformation is a phenotype that is selected for; hence the emergence of tumours). Likewise with BRCA-mutations and familial ovarian and breast cancers, where one mutant copy is inherited, but doesn't confer a phenotype that results in selectable transformation on its own, but with a loss of heterozygosity event that takes out the second hit, does. There are examples abound of traits that are selected for that need two hits in cancer evolution, and without any kind of requirement for simultaneity.