fru has so far been found only in insects; dsx, however, is found throughout the animal kingdom, where it plays a fundamental role in sex determination, and so is of particular interest to researchers.
Using a transgenic tool generated in his lab, Dr Goodwin and colleagues were able to map dsx throughout the fly's development using a fluorescent protein marker that illuminates areas where DSX is active. This highlighted profound differences in neural architecture between the sexes. In males, the researchers were able to show that dsx complements fru activity to create a 'shared' male-specific neural circuit; in females (where fru is inactive), dsx forms a female-specific circuit.
Importantly the researchers were able to manipulate these cells, impinging their ability to function, and show that these circuits are responsible for behaviours unique to the individual sexes.
"It has been suggested that there are only minor trivial differences between the neural circuits that underlie behaviour in males and females," explains Dr Goodwin. "We have shown that in fact there is quite a bit of difference in the number of neurons and how these neurons connect, or 'talk', to each other. These differences can have big consequences on the structure and function of the nervous system."
In addition, while dsx was known to establish the gender of the adult fly, the pattern of dsx activity in the adult was unknown. Dr Goodwin and colleagues have shown that this pattern is not ubiquitous, but rather is restricted in a specific and telling manner.
Some tissues, such as blood cells, may not require a defined gender in order to function. However, others such as the 'fat body', which in the adult fly functions in part to produce hormones, and the oenocytes, which produce sex-specific pheromones, require a specified sexual identity. It was unsurprising to Dr Goodwin and colleagues to find dsx e
|Contact: Craig Brierley|