Question: How To Convert Centimorgan To Base Pair
gravatar for Aurgha
5.3 years ago by
Aurgha70 wrote:

I want to know is there any webtool that can convery centimorgan to base pair

genetics distance • 22k views
ADD COMMENTlink modified 5.1 years ago by Mdperry40 • written 5.3 years ago by Aurgha70
gravatar for Casey Bergman
5.3 years ago by
Casey Bergman17k
Manchester, UK
Casey Bergman17k wrote:

There is no fixed relationship between physcial and genetic distance, so as @vitis points out you need to use empirical estimates from your species/population. If you have this data from markers you can generate a MareyMap to interpolate the relationship between genetic and physical maps (see also this paper).

ADD COMMENTlink modified 5.3 years ago • written 5.3 years ago by Casey Bergman17k
gravatar for Vitis
5.3 years ago by
New York
Vitis1.5k wrote:

Linkage distances (centimorgans) have to be estimated from the populations your study (i. e. counting the recombinants), while physical distances can be identified by mapping your markers back to the genome, if you're lucky enough to have the reference and markers.

ADD COMMENTlink modified 5.3 years ago • written 5.3 years ago by Vitis1.5k
gravatar for Pierre Lindenbaum
5.3 years ago by
France/Nantes/Institut du Thorax - INSERM UMR1087
Pierre Lindenbaum92k wrote:

have a look at the ucsc table stsMap. For some markers it contains both the positions in cM and in pb. You could use those values to make the conversions.

ADD COMMENTlink written 5.3 years ago by Pierre Lindenbaum92k
gravatar for Gustavo
5.3 years ago by
Gustavo510 wrote:

If you need coordinates for the current human reference, you could get the HapMap data set from:


There's one file per chromosome there, listing the chromosomal bp positions for many cM coordinates. The map is dense - for example chr1 lists 256895 positions.

What exactly are you trying to achieve?

ADD COMMENTlink written 5.3 years ago by Gustavo510

I don't know what the OP was trying to achieve, but I found this thread because I'm looking for a relationship chart like this: only using 23&me's Mb/Gb values instead of cM. Using an Average Mb/Gb value and then a range. When comparing my own DNA with others I'm sharing with 23&me does the work for me to predict our relationship, but 23&me allows me to compare DNAs of people sharing with me, but not any predicted relationship between them.

ADD REPLYlink written 20 months ago by dragonbeary0
gravatar for xenophiliuslovegood
5.3 years ago by
xenophiliuslovegood160 wrote:


there is no fixed ratio between a distance given in cM and a distance in bp: it varies according to chromosomes, organism, sex, etc...

If you need a number for a back-of-the-envelope estimation possibly you can use table 1 in this paper:

which gives you (sex-average on human genome) 1.30 cM/Mb (plus or minus 0.80 cM/Mb)

A fine scale analysis seems to be contained here :

(although I haven't read the paper myself)

ADD COMMENTlink written 5.3 years ago by xenophiliuslovegood160
gravatar for Gjain
5.3 years ago by
Göttingen, Germany
Gjain4.9k wrote:

you can use this tool

ADD COMMENTlink written 5.3 years ago by Gjain4.9k
gravatar for Mdperry
5.3 years ago by
Mdperry40 wrote:

This number varies along each eukaryotic chromosome because the meiotic recombination rate can vary along each chromosome (see, for example Barnes at al., Genetics, 1995; for an early analysis comparing genetic map distances in cM to the C. elegans physical map in bp). So there is no simple "conversion" between the two. The previous posts describe the correct approach to calculate the Marey Map (which is what you want).

ADD COMMENTlink written 5.3 years ago by Mdperry40
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