We are building a framework map of known-order anchor markers between the m
ouse T31 radiation hybrid (RH) panel and the recombination map based on The
Jackson Laboratory (TJL) interspecific backcross panels using the establis
hed genetic order to evaluate and strengthen the RH results. In making this
map comparison, we have elucidated several problems inherent in RH mapping
and minimized these by careful attention to data gathering and interpretat
ion methods. We describe lessons and pitfalls of developing radiation hybri
d maps, using the example of mouse Chromosome 18, for which we have built a
framework map of microsatellite anchor loci spanning the entire chromosome
at significant LOD with no gaps. Sixty-five D18Mit- simple sequence length
polymorphism (SSLP) markers form a continuous linkage along the T31 RH Chr
omosome 18 (RH map length 1598 cR, genetic length 41 cM) with all LODs grea
ter than 6. These markers are also placed on TJL interspecific backcrosses,
and the order of the markers in the two systems is in complete agreement.
We are continuing to cross-reference the RH data to TJL backcross data for
the other mouse chromosomes to improve further the power of RH mapping and
to integrate more precisely the extensive existing recombination mapping da
ta for the mouse with the incoming radiation hybrid map data. (C) 2000 Acad
emic Press.