Mapping the genome: some combinatorial problems arising in molecular biology

The ultimate goal of the Human Genome Project and many other efforts in molecular biology is to sequence the chromosomal DNA of humans and other species and elucidate the genetic information contained therein. A less ambitious intermediate goal is to construct physical maps of our 23 pairs of chromosomes. A physical map specifies the locations of markers identifiable fragments of DNA along the DNA molecule. These markers provide a kind of random access to the linear DNA molecule. To locate a feature of interest such as a gene, an experimenter can start at a marker that is known to be close to the gene and “walk” along the DNA until the gene is identified.