Paul Vanouse's talk was concerning DNA imaging, microorganisms and restriction enzymes.
Restriction enzymes cut double stranded DNA at specific recognition sites. These enzymes were discovered in bacteria. They use them to cut foreign DNA (viral) out of their genome, to prevent self cutting the restriction sites in their own genome which are methylated and cannot be detected by the enzymes (see http://en.wikipedia.org/wiki/Methylation).
The recognition sites are normally 4-8 base pairs long and form an inverted repeat. The enzyme cuts DNA either at the same point leaving blunt ends or in a staggered fashion leaving DNA overhangs, the so called 'sticky hands'.
Restriction enzymes are extremely useful in genetic analysis (DNA fingerprint) and genetic engineering (cloning of genes into a vector). After the introduction Paul gave us the challenge to find the cutter of the lambda DNA, a bacteriophage.
The suspects were:
So we went to the lab bench and started pipetting.