WOOD WITHIN A POLAR DINOSAUR BONE

In recent years much attention has focused on the preservation of dino saur bone.(1-3) In such molecular palaeontological studies contaminati on of ancient DNA by human DNA is a major concern, yet contamination b y contemporary plants and organisms may pose an even more serious prob lem since sequences amplified from such material would be less likely to be recognised as contaminants. In this study, we report several mic roscopic fragments of fossil wood located within the marrow cavity of a hypsilophodontid femur from the Early Cretaceous Otway Group, Dinosa ur Cove, south-eastern Australia.(3) The wood is not recognisable macr oscopically and it was only identified as such by thin sectioning proc edures and light microscopy. Thus, if this sample was pulverised for D NA extraction, the extreme sensitivity of the polymerase chain reactio n (PCR) technique could result in amplification of DNA templates of ei ther or both the dinosaur and the wood. The specificity of the PCR app roach should normally preclude amplification of non-animal DNA.(2) How ever in order to amplify ancient and degraded DNA samples successfully it may be necessary to lower the annealing temperature to a level whe re this specificity becomes compromised.