Sexual Dimorphism in Drosophila

Last week, Current Biology released an article about structural differences between sexes in Drosophila melanogaster. It may not be about a human brain, but it’s still neurology and at least semi-related to developmental biology this time.

While the “model” organism displays distinct behavioral differences between sexes, the overall anatomy in regards to dimorphism has been essentially neglected. Previously, the only discernible difference was in the olfactory system. Male olfactory systems have a 25 – 60% larger volume than female flies. Coincidently the male pheromone cVA attracts females while repelling males (however no credible correlation can be made).

Ooooo pretty!

Pretty picture! This is one of many from a collage presented in the article and most interesting to myself as it visibly shows the gender difference in brain size. Magenta is larger in females and green is larger in males.

The article proceeds to explain the fine tunings of specific proteins (fruitless, sex lethal, and transformer) and their effect on dimorphism in a manner that is, quite frankly, far beyond my level of comprehension.

Overall, sexual dimorphism does exist in the Drosophila brain and may influence behavior as a result. A key example of this lies in the activation of fruM (the male version of the fruitless protein) in females and the resulting behavior of courting other females. Now that the anatomical groundwork has been laid the researchers are able to pursue behavioral consequences in future research.


About James R

A twice-over senior at the University of Minnesota - Morris. View all posts by James R

10 responses to “Sexual Dimorphism in Drosophila

  • Rikaishi

    Wait, so someone conducted an experiment which created lesbian flies?

    Not to be immature but these guys deserve medals. And fanart.

    *wanders off back to /u/*

  • Gaebolga

    Sorry to geek you with a question, but I’m a bit curious:

    Do we know if the cool picture shows the differences in the sections of the brain that process olfactory input, or are the differences in other areas?

    Have we even mapped fly brains enough to know?

  • Gaebolga

    Oh, and

    First post!

  • athdead

    And finally, the *only* man in Minnesota who says there is no God has suddenly become an arbiter on mental health…

    *Comment edited by Rev.Frost*

  • andy

    how many neurons do fruit flies have, anyway? and yeah, good question – has any of this been mapped?

  • Gojira 74

    “The article proceeds to explain the fine tunings of specific proteins (fruitless, sex lethal, and transformer) ”

    The ratio of X chromosomes in Drosophila determines the dosage of certain X linked genes that either activate (female) or repress (male) Sexless. Sexless acts as a mRNA splicing enzyme. It targets the mRNA for Transformer making it active. Transformer is a mRNA enzyme that acts on double sex making a unique isoform in females that works to create ovaries, while the “unspliced” double sex in males makes testes.

  • synapse

    @ Rikaishi: They can make males that court other males, too.

  • Moenen

    So what does that mean, a bigger brain area? Are there more neurons? More connections?

    There also seems to be a lot of overlap. Ie both males and females have the circuitry to generate courtship songs. However, only males normally ‘sing’ and females don’t. Miesenbocks group targeted fru expressing neurons in both males and females, and got them both to sing:

  • carldagostino

    Perhaps researchers can map and positively effect the female propensity to buy unneeded shoes and for men to start unneeded wars.( Actually none are needed I suppose)

  • Joan

    Man, can you write – for real! I look forward to reading more of these summaries…a break from the non-developmental-biology community at large can be a fine thing! This is great!

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