MOLECULAR PALEOBIOLOGY OF PROTISTS - AMPLIFICATION AND DIRECT SEQUENCING OF FORAMINIFERAL DNA

Molecular biological techniques are used to reveal or confirm phylogen ies and biogeographic and ecologic histories of fossilizable organisms with great success. Using the PCR (polymerase chain reaction) techniq ue, we have successfully amplified and sequenced ribosomal DNA (18S-rD NA) from benthic and planktic foraminifera. DNA is first extracted fro m single living specimens and DNA templates are prepared. The DNA is t hen amplified using PCR for single and double strands. The direct meth ods using primers developed for protists and fungi allow amplification of the 18S-rRNA gene, a relatively conservative gene useful in phylog enetic analyses. The amplified DNA is sequenced on acrylomide gels usi ng the chain-terminaton method. The 18S-rDNA nucleotide sequences may then be analyzed using standard phylogenetic analytical techniques suc h as PAUP (Phytogenetic Analysis Using Parsimony) or PHYLIP (Phylogeny Inference Package).