Friday, May 28, 2010

Todd Wood and the Neandertal Genome

Todd Wood has written a post on the Neandertal genome and what it means for the origins of modern humans. His post is called the Neandertal Non sequitur and the title refers to his reaction to Fuz Rana's analysis over at Reasons to Believe. But that is not subject of this post.

I should note that he is almost alone in spelling the word "Neandertal" the way the Germans have been spelling it for the last hundred years. Hats off. On to the post. He writes:
In my hominid baraminology paper, I merely cite Darwin's claim that similarities form a pattern that looks like a genealogy, thus supporting the inference of common ancestry.

I've been criticized for this stance, but I'm not going to address those criticisms today. I'll just assert that I'm correct, which I am. The fact of similarity is easy to account for. Being created by one God would be a good reason for some degree of similarity to exist. Likewise, being created to occupy the same world or to participate in the same ecosystem would also necessitate some biological similarity. These types of considerations could explain why all living things use the same basic biochemical building blocks (amino acids, nucleotides, etc.), for example.
And if that were the only thing that supported common ancestry, that would be a defensible position. But it is not. One of the principle reasons that the trees derived from genetic data hold up is that we can look at the fossil record and see corroboration of where those the branches lie. It is not just that we have a record of some Neandertal genes being present in the modern genome. We also have the observed evidence of the morphological similarities between Neandertals and modern humans. In addition, in many places in which these two hominid forms appear, their behavior is hard to distinguish. There are countless other examples.

Genetic evidence suggests a diversification between fish and tetrapods several hundred million years back. Lo and behold, we find fishapods in the Devonian—animals, to quote Sir Arthur Keith, "In the throes of transition." Put simply, the further we go back in the fossil record, the fewer branches we find. This is exactly what you would expect with universal common descent based on evolution. Similarity might be easy to account for in the creationist perspective. When the fossil record is factored in, it is not.

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  1. Good post. True. Clear.

    And if that were the only thing that supported common ancestry, that would be a defensible position. But it is not.

    Correct... And Wood says so in the very next paragraph. Thusly: What these considerations do not explain is the pattern of similarity.

    Wood is admitting that the typical YEC/ID argument doesn't consider how we have not merely similarity, but a pattern of similarity which constantly keeps matching the pattern Darwin predicted.

    So you're not actually correcting Wood; you're actually correcting the same error he's trying to correct.

    With that said, your post is better worded for that purpose than his; I thought you were elegant, brief, and clear, while he was vague and wordy. You even brought in another line of evidence that he didn't.

    But I don't think he was focusing on that; he needed to address Rana's RTB silliness.


  2. Hmmm. Badly worded on my part. The point I was trying to get at, and not doing a very good job of, was that Wood is banging his head against a wall trying to figure out why the genetic similarity is there that Darwin predicted when there is an obvious answer that he is unwilling to consider. The reason he is unwilling to consider it is that he is caught up in the straitjacket of flood geology, which permits no time depth greater than six thousand years and, thus, no evolution. He never even mentions the fossil record, despite the fact that it was as much that record as the observations on the natural world that Darwin used to form his ideas of selection.

    While it is correct that Jerry Coyne's statement that even if we didn't have the fossil record, evolution would still be true, the fossil record is the nail in the coffin. Between the two of them, there simply, in my mind, isn't any doubt.

    It is mystifying that Wood can engage Rana and others so scientifically about the genetics and yet hold to ideas about the fossil and geological records that were discredited and rejected over a hundred years ago. How do you do that and remain credible as a scientist?

  3. I see what you meant; you're right, and the answer to "how can a scientist do that and retain his credibility" is that he can't and doesn't. There's a good reason he keeps his YEC views out of his published papers.

    I think you're possibly missing one small thing about him, though. You're right (I think) that his explanation of the fossil record is hopeless; but he doesn't reject evolution; he attempts to explain it as a QUICK change rather than a slow one. I enjoyed reading his paper on the subject... In short, he thinks it's done through things like transposons. He calls it "genomic modularity".

    Like you said, I think it's too much to swallow; too much of a coincidence to have all the lines of evidence point in the same direction.

    I remembered something he'd written... It's in an article about the Theobald paper (look at the very end). Essentially, he's hoping for a reprieve from protein sequencing: "As I've said before, I suspect that most proteins do not give a consistent phylogenetic signal. At the very least, if the exception has become the rule, shouldn't we be re-examining the rule?" My answer would be that no, we shouldn't; proteins are sequenced by genes, so proteins can't possibly have a different origin from the genes that describe them. IF proteins didn't appear to match the phylogenetic tree, we should look for anomalies in the transcription process, not for alternate origin hypotheses.

    Sorry to bug you... This is all interesting to me.

  4. You aren't bugging me. That is why I keep comments open. You have forced me to be clearer about what I write and I thank you for that. The problem is, as you say, his acceptance of evolution is qualified—it has to happen very quickly and his writings are littered with phrases like "post-flood change", which illustrate the striking juxtaposition of regular science and "folk science" acceptance. As long as he has this sort of understanding of the fossil record, his understanding of evolution will always be skewed.

    Darwin understood, based on the writings of his friend Charles Lyell, that his theory needed deep time to work. While it is certainly true that evolution can act fairly quickly in isolated populations, by and large, the "tempo and mode" of evolution requires quite a bit of time. I was raised on Wright, Simpson, Mayr and Dobshansky (and Goldschmidt when he was thinking clearly) and tend to view things in larger trends (I have branched into punkeek and systematics in my later years, though).

    I remember one of my friends who got his masters degree in anthropology turn to palaeontology for his Ph.D. because he thought that the trends in the human fossil record happened too quickly to figure out exactly what was going on. I don't think he was right but I saw his point about the time depth.

  5. Wood does his 'baraminology' analyses on species and finds groupings corresponding (more or less) to the genus and/or family taxonomic levels. I'd love to see him do a similar analysis of families using the characters defining them, and see whether that analysis produces groupings corresponding to orders, classes and phyla. I strongly suspect that it would. I wonder then how his creationist system would handle it if that turned out to look like the standard phylogenies that are produced by common descent.