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
accomodate
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 650Kbp BAC.
