Hi
I am about to attempt to amplify DNA from
formalin (= formaldehyde) preserved biological
specimens as all ( as far as I am aware)
previous protocols have been unable to amplify
DNA fragments via PCR of more than 200bp
(except in the rare circumstances where the
formalin was phosphate buffered) I am looking
for novel approaches.
I am starting form the premise that the DNA,
contrary to popular belief, is not significantly
degraded in size by the fixation process, but the
difficulties in 200bp+ amplifications result form
the formation of formalin catalysed protein
DNA cross-linking, which DNA polymerases
are unable to read through. A recent paper
provides compelling evidence, in my humble
view, that is the case (listed below). I am
therefore looking for novel approaches to
preferentially disrupt covalent DNA protein
cross links without destroying/modifying the
DNA molecules. I got a few ideas though I
fear they lack sound chemical reasoning.
I would very much like to talk to anybody who,
either has experience of amplifying from
formalin preserved specimens or equally
anybody with knowledge of protein -DNA
interactions and would be willing to give me
there opinion of what might work and what will
not.
If it does prove feasible to readily and cheaply
amplify form preserved museum specimens it
would be a extremely useful protocol.
Thanks in advance.
Guy
Modifications of human and viral DNA by
formaldehyde fixation
Laboratory investigation 1994 vol:71 No 4
pp.604-611
