A. Anand et al., A SEARCH FOR ADDITIONAL X-LINKED GENES AFFECTING SEX DETERMINATION INDROSOPHILA-MELANOGASTER, Journal of Genetics, 77(1), 1998, pp. 27-36
The gene Sex-lethal (Sxl) plays a pivotal role in Drosophila sexual de
velopment. Once activated in response to the X:A ratio signal in XX em
bryos, Sri participates in appropriate implementation of all known asp
ects of sexual differentiation. We have attempted to identify new X-li
nked genes involved in sex determination, especially those involved in
the regulation of Sri. Since misregulation of Sri, or that of the gen
es that regulate it, leads to female-specific lethality, or synergisti
c female-lethal gene interactions, or both, we used these criteria to
screen about 10,000 EMS-treated chromosomes for (i) recessive female-s
pecific lethality or (ii) enhanced female lethality in transheterozygo
us combination with Sri. Four potentially useful mutations-Sxl(dlf), f
l-35, fl-46, l-43-were recovered and a few of their properties were ch
aracterized. Approximate map positions of these mutations were determi
ned by meiotic mapping. To understand their probable position(s) in th
e hierarchy of genes regulating sex determination, we studied dose-dep
endent interactions between them and mutations in genes known to affec
t sex determination by generating double and triple heterozygotes. The
se studies suggest that (i) Sxl(dlf) is not defective in the 'early' r
egulation or functions of Sri, and (ii)fl-35, fl-46 and l-43 are unlik
ely to be a part of the X:A ratio signal, i.e. they are not needed for
the transcriptional activation of Sri. On the other hand, they could
be affecting post-transcriptional processing of Sri transcripts.