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Re: Dino DNA in fossil egg



>                  From the Desk of Chrysalis
>  Dino DNA in fossil egg
> My local paper today carried an article from Reuters that the 
Chinese claim
> to have found dinosaur DNA in a fossilized egg.
> 
> More specifically they said they "discovered organic substances 
that contain
> amino acids in a 'cottonlike' part of the inner surface of the egg's 
cavity".
> The egg is from the central Henan province and is believed to be 70 
million
> years old. 

I have been able to obtain a trace of amino acids from a dinosaur egg 
from the same area and age.  I would like to see the method they 
used because if it was similar to that used by Vianey-Liaud et al 
(1994) in Dinosaur Eggs and Babies, the results would be highly 
suspect and likely contaminated.

> Also that they "found DNA in the egg and succeeded in obtaining a
> variety of gene fragments."
> 

Possible, but unlikely.  The eggs I reported on in the press release I 
posted came from China too and show the best possible chance of 
producing 'Dino DNA'.  It may be that the Chinese got there first :-)

> Other news in the same article (also on China) was about "a diet 
imbalance
> that was traced to the diseased shell of fossilized eggs" being a 
clue to the
> "disappearance of the Jurassic giants."

Of the huge number of eggs from China, I have yet to see one that is 
diseased.  I find it unlikely that the evidence they have can draw a 
parallel between a few (possibly) diseased eggs and the extinction of 
dinosaurs (see below for more info on this - I'll probably argue 
myself into a hole though ;-).

> 
> Any comments, particularly on the latter part of egg shells? Is this a 
new
> twist?

Yes and no.  Zhao has already suggested this in the same volume 
mentioned above.  Whether what he describes is pathological or just 
variation in eggshell morphology between different egg laying 
dinosaurs, remains to be seen.  I have a colleague is an expert on 
poultry eggs and she has shown me some pathological occurrences 
in chicken eggs.  They do not appear to show any similarity to 
previously described dinosaur egg pathologies.  Zhao also records 
trace element concentrations as being higher in the 
specimens collected from horizons with many 'pathological'.  Another 
explanation for this is that the pore waters affected the trace element 
profile causing an enrichment for precisely the reasons Zhao gives 
for the reason for the 'pathologies'.  I don't know of any taphonomic 
study into the preservation of eggs in the fossil record that have been 
conducted... perhaps this is an area for a grad-student or someone 
else to investigate?

Right that's enough from me in this message.  I'l send another related 
message separately.  Watch this space......

Neil


Neil Clark
Curator of Palaeontology
Hunterian Museum
University of Glasgow
email: NCLARK@museum.gla.ac.uk

Mountains are found in erogenous zones.
(Geological Howlers - ed. WDI Rolfe)