Department of Biology, Queens College, CUNY, Flushing, NY 11367 We are interested in understanding TGFb signaling pathway. One of the newest members of this pathway that has been identified is
sma-9. In the last article we published in the Worm Gazette, we wrote about the male tail ray patterning exhibited by
sma-9 mutant males. Besides characterizing male tail ray patterning, we are also interested in figuring out where
sma-9 maps and how
sma-9 may function in TGFb signaling pathway. When we crossed
sma-9 hermaphrodites with wild type males, we got small males in the next generation. That proved to us that
sma-9 mapped to the X chromosome and it had to be recessive because we also got wild type hermaphrodites. We decided to use two-factor mapping to figure out where exactly
sma-9 mapped on the X chromosome. We made three
sma-9unc doubles using three unc genes (
unc-2,
unc-7, and
unc-9) and crossed them with wild type males. In the F2 generation, we looked for rare recombinants (in this case, small nonuncs and unc nonsmalls). Using the data we obtained, we found the map distance (p; Brenner, 1974) of
sma-9 relative to each unc gene and obtained the following results: