Re: the definitions of evolution

From: Moorad Alexanian (
Date: Wed Oct 10 2001 - 10:51:59 EDT

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    This sort of discussions always bring to mind that what one is trying to do
    is to find a metric in the DNA space. Just like we do when we define
    distance in ordinary space. I do not think such a metric has been found.

    ----- Original Message -----
    From: <>
    To: <>
    Sent: Wednesday, October 10, 2001 9:40 AM
    Subject: Re: the definitions of evolution

    > Tim Ikeda wrote in one part of his post:
    > > Well, let's take the chimp/human split as an example. Do we have a
    > > process? Yes. First, we have sex. We have empirical evidence that
    > > do not reproduce exactly. We have evidence that relatively few changes
    > > the development pathways of organisms may have large effects of
    > > -- Changes that even retain or enhance viability. We have evidence that
    > > chimp and human genomes exhibit _tiny_ differences, no greater than what
    > > has even been seen among organisms of the same species. We have observed
    > > numerous modes of speciation in the wild and a few in the lab. We have
    > > observed and even understand the biochemical basis of the generation of
    > > genomic variation. Basically, we have ample evidence that populations
    > > diverge genetically over time and frequently speciate. We may not
    > > know what drives or supports divergence, but it is an observed reality.
    > > Determining whether a process occurred is simple, knowing the exact
    > > the mechanism/s involved at any particular time is the problem.
    > >
    > One thing that does puzzle me is how the chromosomes of
    > related species can be so different in there arrangement
    > in the respective genomes. For example, morphologically,
    > the mouse and the rat look quite similar. Yet the
    > arrangement of the genes on the respective organisms seems
    > very different. Likewise, often the introns also seem to
    > have almost no homology.
    > I don't say this to argue, but unlike Li's lucid
    > description of the globin gene, I find the speciation
    > process quite baffling. In my ignorance at least, I
    > would have expected it to be rather similar.
    > by Grace we do proceed,
    > Wayne

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