Do Fruit Flies Have Gender?
WouterA recent study found that the X chromosome is not the sole determinant of fly gender. Instead, the female determinants on the X chromosome and the male determinants on the autosomes determine a fly’s gender. Flies with two copies of the X chromosome are females, while flies with only one copy of the X chromosome are males. In addition, the X chromosome contains genes that are important for the cell’s function, while the Y chromosome is associated with genes related to spermatogenesis.
Geneticists have spent the last 30 years studying fruit flies to uncover the genetics of sex. During this time, they found a cascade of genes that determine the sex-specific development of organs and tissues. One of the genes in the cascade is called the doublesex gene, and a female fly expresses one version of it while a male flies expresses a different form of it. Baker’s group has referred to this gene as a “master switch” that determines the sex of a fly.
Insects are one of the most diverse groups of organisms on the planet, and the genetic differences between their sex chromosomes are remarkable. For example, grasshopper males have a single X chromosome, and the females have a pair of XY chromosomes. Females, on the other hand, have both XY and XX chromosomes. The females have small eyes and an upward-curved body segment where they deliver their eggs.
