Using labelled dndps have a terminating group. One nucleotide incorporated, cannot add another nucleotide. Using ccd cameras study minute details. Looking at what colour follows cycles & cycles. Short pieces of dna (50-100 bases: real time sequencing. Making use of a polymerize molecule which is fixed to a bottom of a well. Incorporates each nucleotide with a dye on it b/c of the signal attached it, the nucleotide provides a signal and bursts releasing a marker: sequenced genomes. Large variation genome size & gene # In any classifications there are huge amount of variation similarity bacteria & archaea -- dna is densely packed = smaller genomes no introns. Bacteria & archaea increase in genome size = increase in. # of genes doesn"t mean more complexity. Eukaryotes a lot more non-coding, repetitive dna: repetitive dna in human genome. Left over remnants of viral infections: phylogenetic relationships based on sequence data.