Another way to get at this is to look at chromosome spreads from hundreds|
of seedlings in an experimental breeding cross, to learn what the
natural frequency of aneupleoidy or polyploidy is.
Such insanely eye-straining work has actually been done for some plants
(including taro, Colocasia esculenta - by a Japanese research group). In
the case of taro, it was possible to use this approach experimentally to
confirm very low rates of polyploid formation by the rare production of
I do not remember if aneuploids were also found.
>3. How easy is it to break a chromosome in the process of performing the
>preparation and root tip crush?
It is easier to break the cell membranes, and spill chromosomes across
the field of view on a slide - sometimes with the result that it is
unclear which cell the chromosome comes from.
The individual, fully-condensed chromosomes at metaphase are very
resilient in the cell solution, and under the pressures applied a slide
preparation, so they do not break.
Metaphase chromosomes are what we target, usually, when making chromosome
counts. Certain chemicals can be used to arrest cells at this stage in
cell division, in order to increase the chance of being able to make a
Best regards, Peter Matthews (Kyoto)