Unusual sex chromosome creates third sex in Hessian flies

Mar 30, 2010 by Brian Wallheimer

(PhysOrg.com) -- Expectant human parents might wish for a boy or girl, but Hessian flies actually have a third option, and, no matter what, the flies are never surprised by the sex of their offspring.

Jeff Stuart, a Purdue University professor of entomology, and graduate student Thiago Benatti found that a in the mother predetermines the sex of Hessian fly . The chromosome carries a gene called Cm (chromosome maintenance) that can create one of three basic sexes.

"When a mother carries this chromosome, she produces two types of females: female-producing females and male-producing females. Without the chromosome, the mother produces only males," Stuart said. "That means the species is composed of three different sex-related groups."

In humans, an egg contains an , and a sperm contains an X or a Y. When and egg unite, offspring with an XX combination become female and offspring with an XY combination become male. In Hessian flies, however, a female with the unusual chromosome, called W-prime (W') produces only females. Half of her offspring will carry the W' and produce only females, whereas the other half lacking the W' will produce only males.

Cm, one or more on the chromosome, has caused the evolution of the W' chromosome. It arose because the chromosome combination in Hessian flies isn't created at conception, as is the case with humans, but is established by chromosome elimination during .

"I think that the mechanism of embryonic chromosome elimination is an evolutionary remnant of when this insect's ancestors were able to produce offspring without having sex," said Stuart, whose findings were released in the March issue of the journal Genetics.

Understanding the sex-determination process in the Hessian fly could lead to a way to control its populations or eliminate it altogether. The Hessian fly is the major pest of wheat crops, causing millions of dollars of damage annually.

Stuart said it might be possible to genetically modify Hessian flies using the Cm gene to eliminate the fly's ability to produce one of the sexes. Those modified flies could be introduced into fly populations to eliminate it as a pest.

"We're hopefully going to be able to manipulate this to bring the insect to its own demise," he said. "We may be able to use it to drive maladaptive traits into the population."

Stuart said the next step in the research would be to study the evolution of the Cm gene and determine the mechanisms it uses to control sex determination.

Explore further: Producing jet fuel compounds from fungus

Related Stories

X chromosome exposed

May 29, 2008

Researchers from the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, and the EMBL-European Bioinformatics Institute (EMBL-EBI) in Hinxton, UK, have revealed new insights into how sex chromosomes are regulated. ...

Does promiscuity prevent extinction?

Feb 25, 2010

Promiscuous females may be the key to a species' survival, according to new research by the Universities of Exeter and Liverpool. Published today (25 February) in Current Biology, the study could solve the my ...

A sex-ratio meiotic drive system in Drosophila simulans

Nov 06, 2007

If you met a person who had 10 children, all of whom were girls, you would probably find this surprising. Yet this kind of distorted sex ratio does occur in groups as diverse as mammals, insects, and plants, ...

Recommended for you

Producing jet fuel compounds from fungus

12 hours ago

Washington State University researchers have found a way to make jet fuel from a common black fungus found in decaying leaves, soil and rotting fruit. The researchers hope the process leads to economically ...

New technology maps human genome in days

14 hours ago

The two 3-by-1-inch glass chips held the unfathomable amount of genetic information contained in 16 human genomes. Last week, a technician placed the chips - called flow cells - in a new genetic sequencing ...

How does a mobile DNA sequence find its target?

May 05, 2015

To understand how transposable elements shape genomes, where they are maintained over generations, it is vital to discover the mechanisms behind their targeted integration. Researchers from the Laboratoire ...

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.