Fine-Scale Mapping of a Gene

    Every human chromosome has been extensively mapped with molecular markers (top). A gene is initially mapped to a particular chromosome (in this case Chromosome 17), then to the long (q) arm of that chromosome (17q), and then to a particular band of that arm (17q21). The chromosome segment can then be cloned into a set of bacterial artificial chromosome (BAC) vectors that will accommodate several hundred kilobase pairs.  The diagram shows the genetic mapping of the breast cancer locus BRCA1 (~80Kbp)  to Band 21 near the centromere region of the long-arm of Chromosome 17 by means of a 650Kbp BAC.

Figure ©2002 Griffiths et al.; All text material ©2016 by Steven M. Carr