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Re: Dino-fuzz found in amber?



Not in amber:
New evidence for 250 Ma age of halotolerant bacterium from a Permian
salt crystal
"These results support the 250 Ma age of the fluid inclusions, and by
inference, the long-term survivability of microorganisms such as
Virgibacillus sp. 2–9-3."
http://geology.gsapubs.org/content/33/4/265.abstract

(Yeah, there are skeptics about it too - and it is good that they
exhist - e.g.: http://www.springerlink.com/content/pt50ey50xcty01n1/ -
but even if the use the 3/59 correction factor, we'll have 250*3/59 ~
12,5 Ma.)

S. O. Rogers, K. Langenegger and O. Holdenrieder
DNA Changes in Tissues Entrapped in Plant Resins (the Precursors of Amber)
"There have been many reports characterizing DNA from amber, which is
a fossil version of plant resin. Here we report an investigation of
the effects of plant resin (from Pseudotsuga menziesii) and drying
conditions on the preservation of DNA in biological tissues. We
examined the degree of degradation of the DNA by agarose gel
electrophoresis of extracted DNA, by polymerase chain reaction, and by
DNA sequencing. The plant resin alone appeared to cause little or no
damage to DNA. Tissue immersed in plant resin that dried rapidly
(exposed to sunlight) contained DNA with little apparent damage.
Tissue immersed in the resin that was dried slowly (in shade without
sunlight) contained DNA with some degradation (3.5% nucleotide
changes). The tissue that was immersed in the resin that was
constantly hydrated (by immersion in water) yielded DNA that was
severely damaged (50–62% nucleotide changes). Transversions
outnumbered transitions in these samples by a ratio of 1.4 : 1. A
piece of Baltic amber immersed in water for 5 days appeared to be
impervious to the water. Thus amber inclusions that initially dried
rapidly have the potential to yield undamaged DNA. Those that dried
slowly may contain damaged DNA and may be unsuitable for phylogenetic
and other studies."
http://www.springerlink.com/content/nkwfnx34fhatgw21/
----------------------

And there are advances in the paleogenetic techniques:
http://www.sciencedirect.com/science/article/pii/S0169534708001602
----------------------

All in all it still seems to me that try to get DNA from those
protofeathers would be interesting.

[]s,

Roberto Takata

On Thu, Sep 15, 2011 at 8:25 PM, David Marjanovic
<david.marjanovic@gmx.at> wrote:
>>  R DeSalle, J Gatesy, W Wheeler and D Grimaldi
>>  DNA sequences from a fossil termite in Oligo-Miocene amber
>>  and their phylogenetic implications
>
> You forgot to cite the year. It's 1992. Most reports of ancient DNA from
> before the 1997 paper that was just mentioned are due to contamination;
> AFAIK, this includes all that are older than 100,000 years.
>