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 locusBRCA1
(~80Kbp) to Band 21
near the centromere region
of the long-arm of Chromosome 17
by means of a 650KbpBAC.
