Rec-1, isolated and characterized by Rose and Baillie (1979), produces a threefold increase in recombination frequency. Currently our laboratory is investigating the spontaneous mutation frequency of
rec-1 by using the balancing system eT1 developed by Rosenbluth and Baillie (1983). Rec-1 is currently not mapped and its phenotype is scored by examining the recombination frequency as measured in an individual's progeny. In order to have a standardized method for measuring 'high' versus 'low' recombination, we used the frequency of recombination across the
dpy-5 . Strain construction was accomplished in the following manner: Unc-46 hermaphrodites were crossed with Rec-1 males. The resulting male heterozygotes were crossed with Dpy-5 Rec-1 hermaphrodites. The progeny of this cross were
dpy-5 ; or +/+); (
rec-1/rec-1 or
rec-1/+). These individuals were allowed to self fertilize and their progeny were brooded. Crossover frequency was calculated by scoring for Dpy-5 and Dpy-14 progeny. Those plates segregating Unc-46 and exhibiting an elevated recombination frequency were selected and Unc-46 hermaphrodites picked ie.
unc-46/unc-46; -1. The above was then repeated for Dpy-18 and eT1. The three Rec-1 strains were then crossed using Rec-1 males to produce
dpy-18 1; -1.In addition to determining the spontaneous mutation frequency, one month competition experiments between Rec-1, wild type and various mutant populations are being run to determine the differences in life history traits (eg. developmental time, fecundity). These data will provide initial values for parameters such as selection coefficients and mutation frequencies in future experiments. We are beginning several long term experiments to study the evolutionary advantage of recombination.