You still have not answered my post ludde: why are you so against such a
potentially useful model; what is it about the molecular clock hypothesis
that arouses such antagonism (especially in some groups of people)??
Des
In article <3u1c1d$hbh at studium.student.umu.se>, Ludvig Mortberg <Agneta.Guillemot at historia.umu.se> writes:
> Thanks everyone for responding to my sceptical article on the
> molecular clock. Your opinions are valuable. Thanks to them I
> think I'm closer to defining methods of proving or disproving the
> theory of the molecular clock, as I prefer to call it.
>> The following criteria should be satisfied if there is a clock. If not,
> the clock is in trouble.
>> (1) Phylogenies, divergence dates etc, obtained by the clock,
> should conform with fossil data.
Within the errors (stastical and experimantal) inherent in both types of data.
>> (2) When different parts of the genome are used in an analysis the
> results should be the same. Different chromosomes, protein
> sequences etc should give the same divergent dates or
> phylogenies. Of course it may not be possible to draw conclusions
> from data from a very slowly evolving protein. Histones for
> example.
NO!!!!! e.g. the Y chromosome (or parts of it) in mammals goes faster
than the X. e.g. different proteins go at totally different rates if you
use amino acid distances or non-synonymous nucleotide distances.
>> (3) The Wilson relative rate test should be positive when applied
> to three reasonably closely related species. See illustration below:
>> / A
> /
> /
> /\ / B
> \/
> \ C
>> We have determined that B and C are closest. The distance from
> B to A, be it nuclear substitutions or melting temperatures for
> DNA-DNA hybrids, should of course be the same as the distance
> from C to A. Otherwise B and C have evolved with different
> speeds.
>> The last test may be the one that is most useful in determining
> wether there is a clock or not.
>> Now what does the data say?
>
Why don't you look first??
> Ludde
>>
