How do you know whether you are male or female?

Dec 27, 2007

New research published online this week in the open-access journal PLoS Biology investigates this basic and much-studied question in the fruit fly, and comes to a surprising new conclusion.

In mammals, male or female development depends on the presence of the Y chromosome, which is only found in males because it includes masculinizing genes. But other animal groups have evolved different systems. James Erickson and Jerome Quintero at Texas A&M University studied the mechanism of sex determination in the fruit fly, Drosophila melanogaster.

Previous studies in the fly suggested that it was the ratio of X chromosomes (the “female” chromosome, of which there are two copies in a female fly, and just one in a male) to the non-sex chromosomes (the autosomes) that determined the sex of a fly embryo.

However, this new paper indicates that rather than being dependent on the ratio, it is the number of X chromosomes that is important. Sex is determined during a very specific and short stage in embryo development, and only two X chromosomes can produce enough of a signal to feminize the embryo during this window of opportunity.

Citation: Erickson JW, Quintero JJ (2007) Indirect effects of ploidy suggest X chromosome dose, not the X:A ratio, signals sex in Drosophila. PLoS Biol 5(12): e332. doi:10.1371/journal.pbio.0050332 (www.plosbiology.org)

Source: Public Library of Science

Explore further: Diabetes drug found in freshwater is a potential cause of intersex fish

Related Stories

Sex chromosome evolution tracked in fruit fly

Jul 20, 2012

(Phys.org) -- Fruit flies are commonly used in genetics research because their lifespan is short, they are easy to breed in the laboratory, and mutants are widely available. There are about 1,500 known species. ...

New thinking on regulation of sex chromosomes in fruit flies

Sep 19, 2011

Fruit flies have been indispensible to our understanding of genetics and biological processes in all animals, including humans. Yet, despite being one of the most studied of animals, scientists are still finding the fruit ...

Molecular monkey arranges X-chromosome activation

Jul 25, 2013

X chromosomes are very special genetic material. They differ in number between men and women. To achieve equality between sexes, one out of two X chromosomes in women is silenced. In flies, the opposite happens: ...

Recommended for you

York's anti-malarial plant given Chinese approval

Apr 24, 2015

A new hybrid plant used in anti-malarial drug production, developed by scientists at the University of York's Centre for Novel Agricultural Products (CNAP), is now registered as a new variety in China.

The appeal of being anti-GMO

Apr 24, 2015

A team of Belgian philosophers and plant biotechnologists have turned to cognitive science to explain why opposition to genetically modified organisms (GMOs) has become so widespread, despite positive contributions ...

Micro fingers for arranging single cells

Apr 24, 2015

Functional analysis of a cell, which is the fundamental unit of life, is important for gaining new insights into medical and pharmaceutical fields. For efficiently studying cell functions, it is essential ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.