Human Chromosome 2 and Jeffrey Tomkins

Faith & Science Conversation
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The human chromosome 2 is often used as evidence of human evolution. I’ve used it as an example of such for years in my Genetics class. I may need to appeal to those with more knowledge of this topic to answer a few questions, though. (@Swamidass @glipsnort @T_aquaticus come readily to mind) Jeffrey Tomkins at AiG has written (at AiG) pretty extensively on this topic and I wanted to check on a few things. Here is a link to one of his articles:

First, I’ve always taught that the human chromosome 2 arose via Robertsonian translocation (and even said as much in a post here at the BioLogos forum about a month ago). But is this actually true? It seems from the literature that the fusion was an end-to-end fusion and not from a Robertsonian translocation, after all. One of Tomkins biggest objections to the chromosome 2 fusion is that the telomeres are (at least in part) present to prevent end joining, suggesting that this type of fusion should not occur. I know that telomeres also help mitigate the problems with loss of coding information resulting from the 5’ end problem that would arise without the telomere “buffer”. This just has me reconsidering the factual detail I pass on in class.

Second, another of Tomkins’s objections to the fusion hypothesis is the “degenerate” telomere sequence at the fusion point. Am I missing something here? If the fusion did indeed occur in the far-distant past (is there an estimated time of the fusion?) wouldn’t it be perfectly reasonable for the lost-function telomore sequence to have degenerated to the extent that Tomkins describes?

Third, Tomkins notes that sub-telomeric satellite sequences that are prevalent in chimp chromosomes, including 2A and 2B, are absent from human chromosome 2. I don’t have any good reply for this, so any help would be welcome here.

Fourth, Tomkins claims there is no valid evidence for the existence of a cryptic centromere that would have resulted from the fusion. There isn’t as much in the literature as I had expected, at least not from a cursory pubmed search. I did find a couple of independent comments on some bioinformatic work:

Just not a great peer-reviewed article as I would have preferred.

Fifth, Tomkins claims that the proposed fusion site is actually within an intron of the DDX11L2 pseudogene. If I’m understanding his argument correctly, this would indicate that part of the DDX11L2 sequence would have been part of 2A, while the other portion would have been on 2B, which frankly, sounds like a pretty good argument. Any thoughts on this?

Any and all comments appreciated!

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Gee whiz he is going hard after chromosome 2. He probably cares more about it than anyone in the world as if he can just show our current understanding is lacking… then it disproves everything.

I appreciate that with a great lengths that he is going through, but unfortunately from my understanding there are a good many dozen other arguments for common descent. I’d love to look around at this maybe sometime next week.]

What might be a fun lab or project would be for your students in say a Genetics class to sit down and evaluate the data vs. the claims in light of the broader framework of the theory of evolution.

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I don’t know enough specifics of the chroosome2 fusion to speak to most of the questions above. I might suggest, though, that it would be interesting to ask Tomkins or any YEC to explain Chromosome fusions in other animals. For example in canines and equines there is a fair amount of diversity of chromosome numbers. Since YECs believe that all canines and all equines were derived from two pairs of animals they must believe that chromosomal fusion and fission is possible. I’ve always wondered how Tomkins would explain those fusions and at the same time argue that the human fusion is not possible. The closest ancestor of the domestic horse has 66 chromosomes but all domesticated horses have 64. That fusion seems to have some similarities to human chromosome 2. A comparative approach might prove more fruitful than simply trying to respond to all of Tomkins points.

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I think Tomkins would be fine with altered chromosome numbers that result from Robertsonian translocation, it would be virtually impossible to deny. I think his contention is the uniqueness of the end joining-type fusion.

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Sort of interesting that AiG is seemingly a little more testy lately, with this article published on their page yesterday:

Probably deserves a separate post to ferret out the issues. I confess I am over my head with the genetics details and discussion. I will go ahead and make it a new post in case anyone has any comments. It would be nice if AiG allowed comments on their site, but you know how that goes.

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