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Re: Dino-fuzz found in amber?
Am 16.09.2011 03:35, schrieb Roberto Takata:
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."
Those are supposed to be _living_ bacteria which kept repairing their
DNA all the time.
S. O. Rogers, K. Langenegger and O. Holdenrieder
Again you didn't cite the year. Papers are cited by author and year, and
only then by title, journal, volume number and page numbers.
The year is 2000. That's long ago.
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."
Sounds good, indeed promising, but tells us nothing about whether DNA
survives under waterproof conditions for years or millions of years.
And there are advances in the paleogenetic techniques:
That's from 2008, so they really are advances. Well, they mean it's now
possible to make use of more and more degraded DNA, but when there's no
DNA left, they can't do anything either.
All in all it still seems to me that try to get DNA from those
protofeathers would be interesting.
Sure, but I bet it would yield nothing... and so, I'm sure, would any