cM to kbp

Anne Gillen ez049617 at
Mon Sep 13 18:33:31 EST 1999

On Thu, 9 Sep 1999, Bas Jansen wrote:

> In article <19990908182134.15270.qmail at>, ips98 at HOTMAIL.COM
> ("inderpal singh") wrote:
> > Dear All
> >      Hi!
> >      Could anyone tell me what is the relationship between cM (centimorgan) 
> > and kbp (kilo base pairs)? 
> Sure. CentiMorgans (or Morgans for that matter) are derived from
> recombination percentages, thus reflecting the distance between two
> markers on a DNA molecule, a chromosome for example. The distance in
> kbps (or bps for that matter) is simply determined by the number of
> basepairs (A, C, G or T, the buildingblocks of DNA) between two markers
> on a DNA molecule. One cM equals approximately 1 Mbps (not megabits per
> second in our case, but mega basepairs), but I believe one has to take
> into account that the more cM the distance between two
> markers/genes/whatever is, the less accurate the estimate will be for
> the distance in Mbps.
> Bas
> -- 
> bjhj at

I would add that certain areas of a genome may experience more or
less than the average number of recombinations thus not conform to any
simple relationship of cM to bp.  Also,1 cM equals approx 1 Mbp may work
in some organisms but not in others.   


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