Worm Breeder's Gazette 10(1): 14

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Recombinant Inbred Lines Can be Used to Conveniently Map Cloned DNA Fragments

T.E. Johnson

We generated recombinant inbred (RI) lines of the worm to answer 
questions regarding the genetic specification of life span in wild 
populations.  RI lines in both Neurospora and mice are being used to 
map genes based solely on differences in RFLP's between the parental 
strains used to generate the RI lines.  The lines we generated were 
derived from Bristol/Bergerac F1 self crosses and so are segregating 
the several hundred RFLP's that result from Tc1 insertions as well as 
many others.  Any visible single-gene difference segregating in the RI 
lines can be scored to generate a strain distribution pattern (SDP) 
for that marker.  If a second unmapped gene has a similar SDP, that 
gene must be near to the previously mapped gene.  It has been obvious 
for some time that the generation of a linkage map based on the SDP's 
of many RFLP's would be possible, albeit a bit tedious to construct.
Such a map might be useful to us in mapping genes specifying life 
history traits that are segregating in the Bristol/Bergerac background;
but the RFIP map might also be useful as a general mapping strategy.  
Once the RFLP map was well developed one could reveal linkage to 
within 1 map unit, on the average, by simply probing the 43 RI strains 
with the clone of interest; these analyses could be carried out on the 
same set of blots time after time.  RFLP's from different contigs 
could be used to map contigs onto the map relative to each other and 
relative to mapped RFLP's even if some regions of overlap remain 
unclonable using yeast cloning vectors.  Hi-Recombination Inbred lines 
could be generated that would allow fine structure mapping to the 
finest resolution of available RFLP's without necessitating the 
scoring of more than 25 to 50 strains.
The major problem with this idea is that it might be more worm than 
it's worth at the current time.  Nevertheless, I'd appreciate help 
from the worm community in sending me any information which you may 
have collected on RFLP's, mapped or unmapped, or any other single-gene 
trait that is known to differ between Bristol and Bergerac and thus 
should be segregating in the RI strains.