centiMorgans & physical distance: a question

junbug maruta at msvax.mssm.edu
Tue Aug 29 15:34:07 EST 1995


>QUESTION: 
>     Is the Gelehrter and Collins quote accurate? In other words,
>although not precisely linear, does physical length tend to
>correspond to centiMorgan length?
>

The following is _not_ my opinion!! - I just remebered seeing something
like what you describe, so I looked it up.  In p484 of Molecular Cell
Biology (Second ed) Darnel, Lodish and Baltimore, it is written:

	At the molecular level, recombination does not occur with
equal frequency at all sites on chromosomes re in different species.
In yeast, for example, the frequency of meiotic recombination can
vary among different chromosomal sites by a factor of 10; the overall
average recombination frequency in yeast is about 1 percent for
genes that are 3000 base pairs apart.  In humans, the overall recombination
frequency is considerably less, averageing about 1 percent for genes
that are 10^6 base pairs apart.  The distance between genes that have
a recombination frequency is oftem referred as 1 centimorgan, a unit
named for ...

No specific reference is given in the text itself but it is listed
at the end of the chapter.  Maybe you can look it up.



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