Re: Fw: Most popular/common dinosaur misconceptions

[Phillip Bigelow <bigelowp@juno.com>]

On Sat, 19 Aug 2006 21:51:22 -0300 "Roberto Takata" <rmtakata@gmail.com>
writes:
> On 8/19/06, Phillip Bigelow <bigelowp@juno.com> wrote:
> > If polyphyletic life *easily* arises in primordial soups 
> throughout the
> > universe, then the monophyly of Earth life is indeed interesting.
> 
> Possibly. But the genetic pattern shows us that all life that 
> exhist
> today are derived from a single common ancestor - the cenancestor 
> or
> LUCA.
> 
> If there was other living system with independent origin from the
> primordial soup - submarine vent, spacial seeds, whatever - at 
> ancient
> time, they apparently do not have a single descendant living today.
> (Though it could be hide somewhere.)
> 
> An alternative proposed by Doolittle and Woese is that the LUCA or 
> its
> ancestor could be a chimera of different living system with
> independent origin.


Lateral (horizontal) gene transfer?  Yes, that's another possibility.  It
could have swamped out the ancient polyphyletic signal so that it is
undetectable today.


<pb>
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