Question about extracting ancient DNA

[Toby Bradshaw]

In article <23904o$i2e at alnitak.usc.edu> jangus at alnitak.usc.edu (Jim Angus) writes:
>I manage the new Molecular Systematics Laboratory at the Natural History
>Museum of Los Angleles County.  PCR technology will allow the amplification
>of as little as a single molecule of DNA.  Ancient DNA however has several
>problems.  It is highly fragmented and cross linked.  Cross linked
>regions can not be amplified.  Contamination is also a huge problem.  I
>know someone who tried to PCR recent whale bone DNA and got dog DNA because
>dogs had been chewing the remains. 
>
>I've heard that people are attempting to PCR dinosaur bones, but I haven't
>heard anything positive.  
>
>A problem with blood.  Red blood cells contain little DNA.  

Bird and reptile RBCs are nucleated, and contain loads of DNA.

>White blood
>cells do, but are far more rare in blood.  So when looking for dinosaur
>DNA in blood in an insect trapped in amber, it is far more likely that
>you'll end up amplifying insect, plant or some other contaminating DNA.
>You'd need primers VERY specific to dinosaurs or reptiles.

Toby Bradshaw                       |
Department of Biochemistry          |  Will make genetic linkage maps
and College of Forest Resources     |            for food.
University of Washington, Seattle   |
toby at u.washington.edu               |