Chromosomes and Creationism

The above is based on a comment I made in a Facebook group:

The evidence for chromosomal fusion in humans compared to other primates is unambiguous evidence either of common ancestry, or of a Creator who deceitfully made it look like we share a common ancestor with other primates. I cannot fathom why anyone who calls themselves a Christian would choose the latter option over the former. They prefer to make God a liar than to admit that their understanding of the Bible (to say nothing of science) might be flawed.

 

  • Keen Reader

    A sound point irenically made, but it won’t make any difference to the fence-sitters who tacitly give Hamster credence.

  • David_Evans

    I suppose it could be argued that God made Adam out of a chimp. Less work than starting from the ground up. Perhaps towards the end of day 6 He was already getting tired.

    • Jakeithus

      Although your comment is partly in jest, in a case like this determining common descent vs a common designer using pre-existing material is pretty much impossible. It pretty much is what would be argued.

  • Preston Garrison

    There was an argument about this years ago on the old ASA e-mail list, and Cornelius Hunter pointed out that humans could have had chromosomes that looked like chimp chromosomes initially (without common descent) and if the chromosome fusion occurred early and lineages without it died out, you would see what we see today, humans with fused Chr. 2 and apes without.

    I disagree with him on just about everything to do with evolution (it happened), but I had to admit he was right about that. A feature which is unique to human chromosomes can’t be evidence of common descent – it’s the millions of detailed similarities between human chromosomes (including Chr. 2) and ape chromosomes that indicate common descent.

    • http://www.patheos.com/blogs/exploringourmatrix/ James F. McGrath

      Well, the reason for thinking that two chromosomes fused is the number of chromosomes and the matching genetic material including telomeres where they ought not otherwise to be. But even if there were no evidence of fusion, the matching genetic information would still provide strong evidence of common descent.

    • stuart32

      The reason why a unique human feature can provide evidence of evolution is that that feature has to make sense in evolutionary terms. If we share a common ancestor with chimpanzees and we have one less chromosome, then one of our chromosomes must look like two chimpanzee chromosomes stuck together.

      If you look at the picture at the top you will see what looks like a barcode on the chromosomes. That is the banding pattern. The banding patterns are very distinctive. We can use them to match all the other human chromosomes with chimpanzee chromosomes. When that has been done you are left with one human chromosome which exactly matches two chimp chromosomes.

      As James has pointed out, the clincher is the telomeres. Telomeres are distinctive DNA sequences that you find at the end of chromosomes. Where the two chromosomes have joined (if our hypothesis is correct) you find a sequence of telomeres. There is no other explanation for their presence

      • Jakeithus

        Maybe you can explain this better, but doesn’t the statement “The reason why a unique human feature can provide evidence of evolution
        is that that feature has to make sense in evolutionary terms” involve a not insignificant amount of circular reasoning?

        It’s kind of like saying that feature provides evidence of evolution, because if evolution wasn’t true we couldn’t use evolution to make sense of that feature.

        • stuart32

          The point is that the evidence has to be what we expect if evolution has occurred. If two chromosomes have fused then you would expect to find telomeres at the point where the fusion has occurred. Also, it must actually be possible for chromosomes to fuse in the first place. If chromosome fusion had never been observed then that would count against the explanation.

          Do you have an alternative explanation for the presence of the telomeric sequence in the middle of the chromosome?

          • Jakeithus

            I think what Preston was getting at, but maybe I’m unclear about this as well, is that speaking in strictly theoretical terms at least, one could make the case that it would be possible for God to have created our first ancestors with a 2a 2b Chromosome similar to what we see in chimps, which subsequently fused to create the chromosome we see now.

            If evolution has occurred, such a finding certainly fits within its predictions and framework, which I think we all here agree on.

            • stuart32

              That might be possible in theory but in fact it can be ruled out by observing how much the telomeric sequence at the fusion site has mutated and using that to calculate the date of fusion. There is an interesting book called the Relics of Eden by Daniel Fairbanks which has a whole chapter on this very subject.

              • Jakeithus

                Very good. It was never my intention to debate the science behind the idea, just to try and get my head around what I found to be a circular argument involving using the theory of evolution as evidence for evolution.

                I’m not sure I’ve succeeded, but I’m not sure that matters.

                • stuart32

                  That seems to be a particular problem in the evolution debate. What actually counts as evidence for evolution and how do we know it really is evidence for evolution? Consider the fact that the same basic pattern of bones occurs in the human arm, a bat’s wing and a whale’s flipper. This is what you would expect from evolution because evolution can only modify things gradually. It can’t go back to the drawing board and completely redesign the limbs of those animals.

                  A creationist, however, can just say that a designer creates these things in a characteristic style.


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