ABOVE: © ISTOCK.COM, URFINGUSS
The tiny, transparent worm Caenorhabditis elegans can be born either as a male, typically with one X chromosome, or as a hermaphrodite, with two. When Barbara Meyer began a professorship at MIT in the 1980s, she wanted to pinpoint the genetic pathway that determined the worm’s sexual fate. There was evidence that this process was tied to dosage compensation, a delicate balancing act that ensures X-chromosome expression is matched between the two forms—a condition necessary for survival not only in worms, but also in humans, fruit flies, and other animals in which one sex carries two X chromosomes, while the other carries only one.
Meyer suspected that the gene responsible would control the levels of X chromosome expression in only one form of the worm—either it would limit expression in XX C. elegans, or it would boost expression in individuals with only a single X—and failure ...
