Future change in genetic linkage analysis?

E. Wijsman wijsman at u.washington.edu
Sun Dec 10 15:30:03 EST 2000

I think the answer is both yes and no.  The physical distance is useful
for establishing marker order, but doesn't otherwise help in determining
meiotic distance.  Since the accuracy of marker order affects the
efficiency of meiotic mapping, but marker order is difficult to accurately
estimate with meiotic methods for tightly linked markers, it is useful to
have a way to establish order that is independent of meiotic mapping
information.  To the extent that more accuracy in the marker order will
help the mapping problem, then, the physical map will be useful.  
However, trait mapping is based on meiotic distance, not physical
distance.  Unless we find some way to relate physical distance to meiotic
distance more accurately than we can at the moment, I doubt that there
will be additional gains in mapping efficiency obtained by using the
physical distance information, over the improvements obtained by having an
accurately ordered map.

Ellen M. Wijsman                        EXPRESS MAIL ADDRESS ONLY:
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On Sat, 9 Dec 2000, Y.F.LEUNG wrote:

> Hi,
> I came up with a question when I realized the real physical distance
> sometimes differs a lot with the estimated physcial distance from
> genetic distance (with the traditional rule of thumb: 1cM roughly equals
> to 1Mbps) in my linkage analysis.When the human genome project is
> finished, the exact physical position of all microsatellite markers and
> SNPs are known.  I wondered if we can incorporate the real physical
> distance in the traditional genetic linkage analysis (depends on
> recombination fractions or genetic distances) to facilitate a faster and
> more accurate disease trait loci mapping.
> --
> Department of Ophthalmology and Visual Sciences
> Chinese University of Hong Kong
> 3/F Hong Kong Eye Hospital
> 147K Argyle Street, Hong Kong
> Tel: (852) 27623152 Fax: (852) 27159490
> email: leungyukfai at hotmail.com, yfleung at cuhk.edu.hk

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