The present invention relates to a method of comparing at least one
chromosome or part thereof from a cell with a first karyotype with the
corresponding chromosome or part thereof from a cell with a second
karyotype. The method includes the steps of: (a) amplifying DNA from an
isolated chromosome or part of an isolated chromosome; (b) attaching the
amplified DNA to a solid substrate; (c) amplifying DNA from one or more
cells with a first karyotype and amplifying DNA from one or more cells
with a second karyotype; (d) labelling the amplified DNA from the one or
more cells with a first karyotype with a first label, and labelling the
amplified DNA from the one or more cells with a second karyotype with a
second label, wherein the first and second labels are detectably
different; (e) hybridizing the amplified and labelled DNA from the one or
more cells with a first karyotype to the amplified DNA attached to the
solid substrate, and hybridizing the amplified and labelled DNA from the
one or more cells with a second karyotype to the amplified DNA attached
to the solid substrate; and (f) comparing the relative amount of first
and second labels hybridized to the amplified DNA attached to the solid
substrate.