32
Chromosome, Microdissection and Microcloning
(g)
(a)
(b)
(c)
(d)
(e)
(f)
Fig. 4
Sequential steps in chromosome
microdissection. (a) Locate a chromosome
spread on the dissection slide at 10
×
magnifcation, (b) switch to higher magnifcation
to identiFy the target chromosome For
microdissection, (c) rotate the slide to orient the
target chromosome perpendicular to the
dissection micropipette, (d) lower the dissection
micropipette and position the tip proximal to the
target chromosomal band (e) cut the
chromosomal Fragment by scraping across the
band in one Forward motion, (F) apply suction to
the pipette to collect and secure the Fragment to
the tip oF the micropipette, (g) liFt the
micropipette slowly; rotate the stage to bring the
depression slide into the feld oF view. Lower the
pipette, while holding suction, into the aqueous
drop under the oil. Eject the Fragment into the
drop by switching to injection mode.
his colleagues at the European Molecular
Biology Laboratory in Heidelberg. The
methodology was an outgrowth of the
microchemistry work that Edstr¨om had
developed in the 1960s. During the next
twenty years, new technologies emerged
and facilitated both the performance of
precise chromosome microdissection and
the efFciency of cloning chromosomal
DNA.
A
major
contribution
to
these
advances was the introduction of PCR
technology. PCR permits the ampliFca-
tion of minute quantities of template
DNA and generates a product in quan-
tities sufFcient for genetic and molec-
ular analysis. Procedures for preparing
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