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

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