In the human population there are ~100 mutations fixing every single generation. Every single generation. The rate of fixation is equal to the rate of mutation for neutral mutations, it’s faster for beneficials of course. But let’s just suppose they’re neutral.
How many differences are there in these keratin genes in total? Up to a hundred at most. How long ago did the species share common ancestry? (Birds and humans >300 mya) Hundreds of millions of years ago. Let’s just say 250 mya.
Assuming 20 year generation time, that’s still 12.5 million generations. If the rate of mutation is about 50/generation, we get 12.5 million times 50 = 625 million mutations. Is that enough to account for the 30-50 ish we see in keratin orthologoues? Is fiftysmaller than over six hundred million?
Hmm let’s see, is the statement true?: 50 < 625 000 000
I’m going to say: Yes. 50 is smaller than 625 000 000
Doing some quick math, human keratin protein (type II cytoskeletal 1) is 644 amino acids long. Factoring in 3rd base wobble, let’s call it 1288 bases for nonsynonymous mutations. Divide that by a 3 billion base genome and multiply that by your 625E6 and you get 268 mutations, well above the 50.
We also know that epistatic interactions do not require a neutral mutation to be fixed in a population, so that dramatically widens the pool of neutral mutations that could interact with subsequent mutations. Looking at the variant table at Ensembl, there are 575 known missense variants for KRT1 in the human population (assuming there aren’t repeats in the list).
So basically it’s been mutating considerably below the overall genomic rate (as protein-coding genes generally do), which reflects purifying selection. That is to say, the number of differences between keratin orthologoues in different species are way below those expected simply from mutation alone. Of course, if the differences were higher than those expected from the rate of mutation, that would just imply positive selection instead.
There is just no possible world in which the number of differences are too high. But ID proponents have been hoodwinked into focusing on “target” mutations and “coordinated” changes, taking the differences we see as a sort of “target” that had to evolve, instead of just another set among innumerable possible variants.
It never crosses their minds to consider how many possible epistatic interactions there are, nor how many variants can exist in a given population. It is really strange that they think epistatic interactions require fixation of a mutation. Little did I know that proteins talk to one another and promise not to change their structures until all of the other proteins have the same sequence. Who knew.
“Reptiles use keratin for their scales, so all scales must have keratin and all keratin must be used for scales! So if John said fish don’t have keratin in their scales, they must not have keratin at all! So I’ll post an article showing that fish DO have keratin! That’ll show him!”
Ah, but we have legal concepts for this which are highly useful here. There are such things as “primary” and “secondary” liability. So, if I fail to provide a tenant a secure building, and the tenant is robbed, the tenant may sue me for damages. But the robber is the primarily liable person, so if I can find him, I in turn can hold him responsible by way of indemnity to me.
If, arguendo, you have some responsibility for unleashing the dogs of reckless ID Creationist nonsense by asking legitimate questions (I should think not, unless these questions were asked with deliberate disregard for the mental health of all nearby; but I was never much of a tort-law theorist), it is clear that the same principle would apply. Those who actually post the nonsense are primarily liable, and your liability can be secondary at most.
The difference, of course, is that they would never apologize except in the apologetical sense.
This raises the interesting question of is it possible to secure a thread against Creationist nonsense? If not, the options would appear to be either to be completely silent or to accept that such nonsense may eventuate.
I would therefore suggest that, by our participation in this, or any other forum of potential interest to Creationists, we are equally as liable as @dsterncardinale.
I think that’s fair. Who here can say that he can resist the temptation, upon seeing something crazy as a tree full of rats, to poke it with a stick and see what happens? If only the DI were not playing the role of Willard.
Bleakest moments? Remember that we’re dealing with people who think the election was stolen and, even more incredibly, that Stephen Meyer is an honest man – and who, after having been met by devastating rebuttal from scientists specializing in the various points in issue time after time, just keep popping up saying, “Bleah! There’s no way to account for biological novelty! Bleah!”
In that environment, madness is the rule, and statements are deemed controversial in inverse proportion to how legitimately controversial they actually are.
Do you believe that evolving the keratin genes to allow a bird to fly (flight feather) did not require any specific mutations? A random walk to flight?
Is your hypothesis that neutral mutations fixed by Kimura’s model formula lead to flight without any type of search? Search types as discussed by @Art in his 2004 discussion of Axe’s work.
Why do you think Michael Lynch did not simply use Kimura’s math (as you did) as a model and counter argument to Mike Behe?
Earlier organisms were not searching for ways to fly. They were just using trial and error to find better ways of surviving. It just happened that those better ways finished up with an ability to fly.
Good point (although you used the same teleological language as Bill). Similarly, the delta variant of SARS-CoV-2 wasn’t actively searching for mutations that would make it more transmissible than other variants. It just happened to be the variant that experienced those transmission-enhancing mutations.
