pz

Great gog. Malachi256 has just said,Am I the only one left with his jaw on the floor by that incredibly erroneous comment?

Jimmy Higgins

Why are you surprised?

pz

I had thought that even young earth creationists could do simple third grade arithmetic.

Jimmy Higgins

Problem is, and you already know this, that person doesn't know what any of those numbers mean. You can't argue against such blatent ignorance.

RufusAtticus

Quick question: How many gametes do dogs have per generation?

PZ, thanks for the summary.

pz

Now that's an interesting question.

Total dog population in the US alone is 5 * 10^7.

A typical number of sperm per ejaculate is also 5 * 10^7 (guessing from a normal human sperm count).

If we are brutally conservative and assume each male dog (female gametes will be a million-fold rarer, and are thus negligible for this analysis) only breeds once a year over a reproductive lifetime of 10 years, that's 1.25 * 10^16 true blue good ol' American canine gametes. About 130,000 gallons of dog semen.

Somehow, I suspect malachi256's estimate is a wee bit off.

Doubting Didymus

That's a trick question. My first thought was "What? Well two of course! Oh wait..."

(Am I right in thinking that malachis calculation would be correct, if there was one dog in existance at any given time, and it reproduced asexually?)

pz

Maybe. Remember, he said 1 in 10 dog genes, and that mutation rate is per gene. Each dog is going to have about 30,000 genes. That's going to be about 0.3 mutations per dog per generation. If you assume a solitary dog makes one gamete per year for 10,000 years, that would be 3000 total mutations, or 1/10th of the total.

Poor lonely little mutt.

Doubting Didymus

Yep. That's what I gathered malachi is thinking with his calculation. I don't know why it made your jaw drop. Ignoring sex is just about the most common mistake creationists make when making 'not enough mutations' arguments.

pz

It also requires ignoring population size, though. Rather than 1/10 of the genes getting hit once in 10,000 years, it means that in a moderate sized population, every gene gets a hit every generation. That's a rather dramatic difference.