Re: BYU dino DNA

[George Engelmann <engelman@cwis.unomaha.edu>]

Blaise Condsidine writes,
>I heard (read) somewhere that the bones from which the BYU folks
>extracted the DNA were NOT fossilized, but had been buried in peat. Can
>this be so, and if it is so, what are the implications regarding the DNA
>within? Wouldn't soaking in peat for millions of years play just as much
>havoc with the DNA as undergoing fossilization?    
Any organic remains that get to be that old are fossilized. Since the 
definition of what constitutes a fossil includes an age criterion 
fossilization simply refers to any process that preserves organic remains or
traces long enough for them to be considered fossils. What most people mean
when they speak of fossilization is mineralization or other alteration that
tends to enhance the preservability of the remains. In fact, there is a popular
misconception that I often encounter that all fossils have been "turned to 
stone", replaced by minerals. Actually, many, if not most, vertebrate bone
preserves at least the original mineral matter. Fossilization can be 
a rather passive process as well. If organic remains find their way into an 
environment in which its materials are stable, they can endure for the 
thousands or millions of years it takes to become a fossil. In the case of
peat, the peat and anything in it must have been in an oxygen deficient
environment so that the organic compounds would not have been destroyed by
oxidation as is more often their fate. But that would not make them safe from
alteration. Preservation of organic molecules intact would depend on their
own stability, the temperatures they were subjected to, exposure to fluids
and bacterial action, to name a few important factors. It would seem that peat
would be rich in all these factors, at least early on. So, it seems likely
that there must have been additional considerations, such as some means of 
physically sequestering the material, if the DNA is indeed ancient.

GFEngelmann engelman@unomaha.edu