The C. elegans hermaphrodite can be considered as a female that makes sperm for a short period. This pathway allows the required transient switch of the hermaphrodite germ line during the L4 stage to the male mode and then back again to the female mode. TRA-1 is most closely related to the transcription factor Ci in Drosophila and the gli oncogenes in mammals, which are target proteins of hedgehog and Sonic hedgehog pathways, respectively. However, HER-1 shows no significant similarity to Hedgehog. The her-1 and hedgehog pathways are probably only distantly related if at all.
Dosage compensation equalizes X chromosome expression in the two sexes .
In C. elegans the genes for dosage compensation control X expression by globally regulating transcript levels of X-linked genes, implying a common regulatory element for most of the genes on the X chromosome. The genes controlling dosage compensation have been identified by mutations that effect X chromosome expression and were identified as sex-specific lethals. The SDC gene products are part of a complex in XX animals that binds to the X chromosome at many sites, apparently changing the chromatin configuration to globally turn down X-linked gene expression by a factor of two. All organisms have sex determining genes that direct development along one or the other of two dimorphic pathways. If sex is chromosomally determined, some mechanism of dosage compensation is required to equalize sex chromosome expression in the two sexes.