Male mice have unexpectedly been found to switch sex if they lack a gene previously linked with lung development.

If the same is true in humans, it might help to explain why some people who are genetically "male" - they have a Y chromosome - develop female genitals.

"It could be involved in cases of human sex reversal," says David Ornitz, head of the team that made the discovery at Washington University Medical School in St Louis, Missouri.

The researchers suggest screening the DNA of people with sex reversal to see if they have mutations in the gene, or in other genes which activate it.

Arrested development

Sex reversal occurs in one person in every 20,000, but only 10 per cent of cases have been traced to known genetic causes. Could it be, says Ornitz, that defects in a gene called Fgf9 are to blame for some of rest? The gene makes a substance called fibroblast growth factor nine.

Ornitz and his colleagues stumbled upon the sex link during experiments to investigate how lungs develop in mice. They genetically engineered the mice so that Fgf9 no longer worked.

Sure enough, the lungs did not develop and the mice were all stillborn. But the surprises came when he took a look at the prostate gland, which was also suspected to rely on Fgf9 for development. To his surprise, there were no prostate glands, or male genitals in the 10 of the 12 "male" mice with Y chromosomes.

"It looked like complete sex reversal," says Ornitz. "The male sex organs had completely regressed." Instead, the "males" had all developed female sex organs.

Down stream

Geneticists in Britain established in 1990 that in mice, and probably in humans, the master gene determining maleness isSRY. The gene makes a switch called a transcription factor that activates other genes and sets in motion the formation of male sex organs in most mammals.

Ornitz believes that Fgf9 works further along the production line. He suggests that fibroblast growth factor nine performs at least two crucial functions. First, it triggers multiplication of cells crucial to the development of the testes. Second, it tells them to migrate to the site where the testes develop.

"In the absence of these first two events, the testicular cords fail to develop," says Ornitz. Ultimately, female sex organs develop instead by default.

Sending signals

Robin Lovell-Badge, the geneticist at the National Institute of Medical Research in London who discovered SRY in 1990, says that the finding is important.

The crucial thing is that unlike the transcription factors produced by SRY and another important "downstream" gene called SOX3, the newly discovered gene leads to signalling between cells.

"That seems to be very important," says Lovell-Badge. "The evidence for migration looks very strong."


BAGHDAD -- Finally responding to nonstop attacks against American soldiers and citizens in Iraq since the U.S. invasion last year, the White House today announced that it had rehired Saddam Hussein as the country's dictator.

"It's pretty clear that, at this time, Iraqis can't deal with being free," Press Secretary Scott McClellan said during the announcement. "Being free doesn't mean free to kill Americans, you know. We think Saddam can correct the situation."

"Oh shit!" said the nation's Sunni, Shiite and Kurd populations in a joint statement, suddenly remembering life under the brutal dictator. "Can we start over?"

The move comes after Iraqis in the northern city of Fallujah attacked and killed four U.S. contractors, mutilating their corpses and chanting, "Fallujah is the graveyard of Americans!" and "We sacrifice our blood and souls for Islam!"

"Fallujah's probably gonna be the graveyard to a bunch of stone-throwing heathens now," quipped Defense Secretary Donald Rumsfeld. "Well, fuck 'em -- if they can't appreciate the life of freedom, lets give 'em death courtesy of Saddam."

Asked how America's one-time friend could become America's enemy and then become America's friend again, Rumsfeld scoffed.

"Friend? Look, differences of opinion aside, we've come to recognize that Saddam had a stabilizing effect on the region," Rumsfeld said. "Sure, we're not a fan of his human rights record, invasions or taste in palaces, but he kept those crazy Islamians in line."

"Besides, I don't recall anyone in this Administration ever called Hussein 'a bad guy' in so many words," Rumsfeld added, using finger-quotes. "It's the media who went and made him out to be the Hitler of the Middle East, you know."

Hussein, for his part, appears prepared to take on a new challenge.

"Everyone ask Saddam, 'You ready Saddam?' every minute since Saddam leave cell!" said the once, present and future dictator, whose bedraggled appearance belied his apparent resolve to rule Iraq with an iron fist.

"Saddam say, 'Saddam ready! Give Saddam rifle!' Ah, thank you, American infidel people -- Uncle Saddam so very happy! Celebrate tonight! Slay 10,000 Iraqis for disorderly conduct!"

"Oh shit!" said the nation's Sunni, Shiite and Kurd populations in another joint statement.


Search giant Google announced on Monday that it would acquire the hot young video-sharing website YouTube, in a $1.65 billion stock deal.

Apply-google-adsense YouTube has soared in popularity since launching in February 2005 and estimates that more than 100 million videos are watched by visitors to its website each day. The site offers free content, ranging from home videos to snippets of Hollywood films, television shows and concerts.

"The YouTube team has built an exciting and powerful media platform that complements Google's mission to organise the world's information and make it universally accessible and useful," Google's chief executive Eric Schmidt said in a statement.


Clip culture

"Our community has played a vital role in changing the way that people consume media, creating a new clip culture," said YouTube co-founder Chad Hurley. "By joining forces with Google, we can benefit from its global reach and technology leadership."

Hurley and YouTube's other co-founder, Steve Chen, posted a video to the front page of their site announcing the acquisition and thanking the YouTube community for helping make the site a success.

Once the acquisition is complete, YouTube will continue to operate independently from its headquarters in California, US. All of YouTube's 65 employees will also remain within the company.

The alliance will see Google attempt to apply its expertise in generating revenue through online advertising while YouTube will provide Google with a big slice of the online video-sharing market. Google's own video service, Google Video, has failed to take off.

"We think one of the keys to comprehensive search experience will be video," said Google co-founder Sergey Brin. "On the whole it is hard for me to imagine a better fit with another company. YouTube really reminds me of Google just a few short years ago."

Studio agreements

Google said the deal was done as a stock trade in order to provide YouTube owners with a tax break while making the takeover cost efficient. The acquisition should be finalised by the end of 2006.

The deal was announced on the same day that Google and YouTube unveiled agreements with major studios to post copyrighted music videos online. The deals are seen as an effort to pre-empt accusations of copyright infringement and enlist studios as potential beneficiaries of the online video-sharing trend.

Hurley added that YouTube was putting new systems in place to "fingerprint" copyrighted material so it could be tracked. "We are committed to develop tools that help identify content and monetize it in new ways," Hurley said.

"Most people believe that this is just the beginning of a video internet revolution," Schmidt added. "I think there is a whole new ecosystem and we are expecting to be a part of it." Meanwhile, Schmidt said, Google Video "will not go away now, or ever".