Friday, 30 January 2009

99% Ape - ch1: 99% Ape

Mutations in HIV

A diagram showing the tree of mutations in a strain of HIV in a dentist and four patients is given on p.9. The text says that patients A, B, and C were shown to have received the virus from the dentist, but that patient D was not.

The diagram, however, shows that the mutation that lead to patient B's virus strain occurred 'before' that of the dentist (or, at least, that the differences between it and the dentist's strain suggest an earlier divergence). What was the conclusion wrt patient B?

Evolutionary Trees

Q: Where did HIV come from?

A: HIV and SIV (Simian Immuno Virus) are closely related [[M] by examining their genomes?]

Q: Where and how did SIV develop? Since when is it known to exist?

Darwin, Apes and Victorians

Biblical account of Genesis
  • Humans created in God's likeness.
  • Species separately created ("Special Creation")
  • Each 'type' of animal is fixed
    • Similarities show design plan commonalities

    Darwin saw similarities as a consequence of evolution.

    Alfred Russel Wallace in 1859 was going to publish his theory. Darwin said it was "an excellent short abstract" of "On the Origin of Species".

    Evolution - the idea - was not invented by Darwin. Many others before him believed that species changed (such as Erasmus Darwin 1731-1802)

    Joseph Dalton Hooker - friend of Darwin's to whom he wrote about his initial thoughts on evolution.

    Darwin's contribution was to discover a method by which evolution works.

    While Darwin knew nothing of viruses, his theory perfectly descries how they change over time - one major piece of evidence for evolution by natural selection.

    Darwin's Insights

    The third point on page 14 states that the idea that evolution occurs gradually has stood the test of time. There does, as far as I am aware, appear to be evidence that, given the right environment (e.g. a new, unpopulated territory, or niche), organisms will evolve (diversify) rapidly to fill that niche, and then slows down once the 'hole' has been populated.

    What's in 1%?

    What are the counter claims against "99% similar"?
    They are based on other ways of measuring difference.
    Q: What are these, and how relevant are they?

    Many of the differences are likely switches which turn genes on or off - this allows a much greater effect than would be suggested by a small change.
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