Common ancestry - direct evicence?

From: Peter Ruest (pruest@pop.mysunrise.ch)
Date: Sun Mar 24 2002 - 09:55:51 EST

  • Next message: Tim Ikeda: "Re: Common ancestry - direct evidence?"

    Is there any _direct_ evidence for common ancestry between humans and
    apes?

    Of course, there is a lot of evidence for this, particularly in the
    field of DNA sequences. For various reasons, I am convinced humans and
    apes are biologically related by common ancestry, but I am not aware of
    any _direct_ evidence for this.

    Although the similarity between corresponding DNA sequences of, say,
    human and chimpanzee may be statistically highly significant, common
    natural selection may possibly account for this (parallel or convergent
    evolution). Therefore, the significance of the evidence for common
    ancestry is directly related to the _lack_ of functionality of the
    sequences under consideration.

    Now, a pseudogene or other unused sequence which has evolved for the
    last 6 million or more years in the ancestors of humans and chimps in an
    exactly neutral way is, presumably, under no selective pressure. But is
    it possible to demonstrate that such a sequence has not been used at any
    time in either line of descent for any function, coded or non-coded?

    Presumably, any single unused sequence will be too short to give a
    sufficient signal-to-noise ratio to provide a definitive answer.
    Therefore, large sets of such sequences would have to be tested
    together.

    Have any such "phylogeny-indicator" sequence sets been documented?

    (By the way, the same argument applied here to similar sequences under
    common selection is equally applicable to similar cladistic trees of
    molecules which are interdependent in each organism. In this case,
    independence would have to be demonstrated.)

    Peter

    -- 
    Dr. Peter Ruest, CH-3148 Lanzenhaeusern, Switzerland
    <pruest@dplanet.ch> - Biochemistry - Creation and evolution
    "..the work which God created to evolve it" (Genesis 2:3)
    



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