Three-stage approach of the Human Genome Project.
  • Cytogenetic map Chromosome banding pattern and location of specific genes by fluorescence in situ hybridization ( FISH ).
  • Genetic (linkage) mapping Ordering of genetic markers.
  • Physical mapping Ordering of fragments cloned in phage and plasmid vectors; this gives the actual distance in base pairs between markers.
  • DNA sequencing Determination of nucleotide sequence of each small fragment and assembly of the partial sequences into the complete genome sequence.