Re: Final Solution of the Aquatic Question


Pauline M Ross wrote:
> On Sun, 07 Aug 2005 21:04:38 GMT, "Rick Wagler" <taxidea3@xxxxxxx>
> wrote:
>
> >Thanks for flagging this. It is an interesting read but
> >Marc's preferred scenario is far from the only one
> >indicated.
>
> If by that you mean there is some aquatic take on this, I would say
> that the only conclusion that can be drawn is that our ancestors were
> not on mainland Africa at the time of the retrovirus. It might have
> been an offshore island, it might have been mainland Asia, but it
> doesn't suggest anything particularly aquatic (even though it fits
> with a number of proposed aquatic scenarios).


This is not at all the only conclusion that can be drawn. Also
possible: members of the proto-human population had developed a
resistance to infection and/or infections never completely hit all of
the species and/or their population was sufficiently large such that
those who were marked by retroviral infection never saw that part of
their genome reach fixation. The retroviral inserts become alleles at
a particular locus in essense and are subject to all the same forces as
any other locus with regard to properties of population genetics. Also
possible is that the exposure dates are off considerably. I discount
the molecular dates because the calibrations are sketchy and the
assumptions about rate regularity are often violated.

> >Firstly taking the data at face value means
> >that primate phylogeny has to be reworked to produce
> >a human-orang-gibbon clade versus a gorilla-chimp-
> >Old World (Cercopithecid) monkey clade and this just
> >conflicts with too much other data to be realistic.

> I'm not sure why you think that. The existing arrangement is still
> perfectly feasible, I would have thought.

Richard is right. Base ONLY on the data, considering nothing else, a
new phylogeny is suggested. However, there is abundant evidence that
these data are the anomaly and should be discounted when assessing
phylogeny as virtually everything else suggests the (OWM(G(O(C-H-G))))
splits. If the retroviral markers were conserved from deep ancestry,
they do violate this pairing.

> >The
> >argument for the line leading to Homo abandoning Africa
> >3-4 million years ago and then re-entering while not impossible
> >has absolutely no fossil evidence to back it up.
>
> Well, there's no need to presume they abandoned Africa and re-entered
> it. How about if there are populations of hominids all over the place
> - including some outside Africa? When the retrovirus hits, the African
> populations are decimated. Later, the African and non-African
> populations are able to meet up again and the non-Africans
> predominate, thus eliminating the signs of the retrovirus in human
> ancestors. Is that feasible?

I don't know anything about the epidemiology of this retrovirus, but
there's no need to assume that it decimated any populations or even
that it's particularly dangerous (or even that those infected know it
at all). There's also no need to assume that all members of a species
are going to be infected and consequently, no reason to assume that
infection in some will lead to the genetic marker in all subsequent
generations.


> [Snip]
> >In any event this is fascinationg stuff and we will have to
> >see where it leads.
>
> Indeed. I've been looking forward to some informed debate on this from
> the professionals. It's been much discussed on the AAT group, but no
> one there is an expert in these matters.

.

Relevant Pages

  • Re: Final Solution of the Aquatic Question
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