In two earlier articles (find the full series here), I revisited YouTuber Dave Farina’s engagement with me on biochemist Michael Behe’s work, noting varied substantive points with Farina’s understanding of the related material. On this third installment, I’ll assess Farina’s dialogue of the Vpu protein in HIV-1, which he had beforehand provided as a counterexample to Behe’s thesis in The Fringe of Evolution.
Farina remarks,
One other instance I discussed within the Behe debunk is the VPU protein in HIV-1. It developed the power to counteract a part of the human immune system that’s completely different from different apes, a totally new perform, with out shedding its ancestral perform.
Factually Correct, However…
Farina’s illustration of this instance is factually correct. Nonetheless, this adaptation was achieved by way of minor modification of an present viral protein (particularly, adjustments to the transmembrane area) relatively than de novo creation of a brand new protein. As I famous in a previous article addressing Farina, Vigan and Neil mapped the important thing adjustments to particular residues (particularly, A14, W22, and to a lesser extent A18) within the transmembrane area.1 These residues cluster on one face of the alpha helix and are essential for tetherin interplay and antagonism. Farina responds,
Jonny makes an attempt harm management right here too. First he references a totally completely different paper which investigates just one area of the protein, as a substitute of the paper I referenced which investigates two areas, specifying that diversifications in each of those areas are required for the novel exercise. The paper Jonny pivoted to examines solely certainly one of these. Creationist cherry choosing at its best.
Nonetheless, whereas adjustments in each segments of the transmembrane area do contribute to optimum perform, the strongest results come from the central cluster (particularly A14 and W22). Mutations affecting the N-terminal section have weaker results and principally contribute to effectivity relatively than being strictly vital. Certainly, past the three amino acid modifications I referred to in my earlier article (and above), no different residue adjustments are required for the core tetherin-antagonism perform of HIV-1 Vpu.
Farina additional feedback,
It’s additionally value noting that one other research a special HIV subgroup, HIV-1N, confirmed 4 amino acid substitutions that activated VPU towards human tetherin, that are completely completely different from those within the research on HIV-1M. So this instance additionally debunks one other traditional creationist straw man, the concept there is just one solution to get a selected perform. Two completely different units of mutations yielding the identical novel perform in two completely different subgroups of the virus. Isn’t it pretty when one instance debunks two creationist speaking factors on the identical time?
It’s true that having a number of combos that obtain a fancy adaptation will increase the likelihood of discovering certainly one of them by probability. Nonetheless, because the variety of required co-dependent mutations for a selective profit to be realized, the likelihood that there are different combos decreases.
Contemplate that, for a two-residue interplay, the variety of prospects is 202, or 400. For a 3-residue interplay, the quantity jumps to twenty4, or eight thousand. For a 4-residue interplay, the combinatorial house is as excessive as 204, or 160,000. For a 5-residue interplay, the variety of prospects is 205, or 3.2 million. Except the variety of options grows proportionally, the fraction of adaptive combos drops dramatically.
Farina additional states,
After that Jonny decides to whine about how none of it issues and this instance doesn’t depend, as a result of it’s in viruses which mutate so quickly. No truthful! OK then, moron.
A Restricted Grasp of Inhabitants Genetics
Farina’s dismissal of this vital level means that he doesn’t perceive the topic of inhabitants genetics very nicely. Viruses corresponding to HIV have huge efficient inhabitants sizes, very excessive mutation charges, and intensely brief era turn-over instances. These render multi-mutation results vastly extra possible than in micro organism, not to mention multicellular organisms corresponding to animals. If complicated diversifications can occur wherever, they’re most definitely to happen in viruses. Even this explicit case shouldn’t be particularly spectacular given the extremely optimum situations for viral evolution relative to larger life-forms.
Within the fourth installment in this series, I’ll appraise Farina’s dialogue of bacterial flagella.
