[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: "Scientists in raptures over flightless Fred"



> "The geneticists who want to get their hands on 
> this will be skipping down 
> the street," he said, after bringing the last of the
>  remains to the surface. 


> "Then you can work out how it actually got to
> Mauritius, because it  must 
> have originally flown here before evolving into
> flightlessness and the big,  fat 
> bird that we know," he said.  "We know it's a giant
> pigeon," he  added.

No you won't. The route by which it got there is
fairly certain; it's not like there were many
possibilities - but the dodo ancestor remains are all
under hundreds of m of seawater now (and probably
dissolved). To believe that DNA sequences could
properly resolve the basal polytomy out of which the
didines emerged without any fossil record is simple
folly. And the fossil record of basal Columbiformes is
precisely zero I think (or not, Tommy? Is _Gerandia
calcaria_ still the only real - or presumed - columbid
fossil older than 5 Ma, or do we have something form
Australia by now? Not that the latter would be very
useful as regards this question) The dodo ancient DNA
study that was published contained a likely case of
LBA (with emphasis on "long", i.e. more than halfway
across the tree), which was not even discussed. It
should have been tried to force the Passenger Pigeon
and the cuckoo-doves (IIRC) into their actual
relationships - for which there has been a consensus
since some time - and see what that would do to the
tree. Wasn't. Though I don't think it could have
resolved it better, at least it could have hinted at
whether there was an intriguing molecular homoplasy or
simple contaimnation of the PP sample.

It was, to paraphrase Graur & Martin (2004), like
trying to reconstruct proto-Indo-European with the
help of the Oxford English Dictionary and a
phylogenetic tree that placed Albanian next to Ojibwe.


> nonsense", he said,  adding 
> that the remains were highly fragile.  "If you try
> and pick it up,  it just falls 
> apart," he said.

So the cances of extracting meaningful DNA from this
are, ehm, *rotten*, just like getting some from _Homo
floresiensis_? Ah, we'll have to wait and see.

The accumulated data permitted sinking the Raphidae
into the Columbidae for reasons of monophyly. But
that's about it :( If there's anything that could shed
light on the matter, it's not ancient DNA, but an
articulated fossil of the "right" columbid from Late
Oligocene India.


Regards,

Eike


      __________________________________  Alles was der Gesundheit und 
Entspannung dient. BE A BETTER MEDIZINMANN! www.yahoo.de/clever