The enormous difference between male and female sexual behavior may be explained, in animals at least, by a tiny organ in the nose rather than by any gender difference in brain circuitry.
So say investigators in the US, who admit to being stunned by the finding and the implications for the understanding of sexuality.
In a study published yesterday by the British journal Nature, the team engineered female lab mice so that the rodents lacked a gene called TRPC2, effectively short-circuiting the so-called vomeronasal organ.
This tiny organ in the nose is packed with receptor cells that pick up pheromones -- primitive scents that trigger aggression and sexual responses in land-dwelling vertebrates.
To the scientists' surprise, the mutant female mice behaved like men at a Seventies disco night.
They sniffed and ran after females, flounced their pelvises, mounted and thrust at male mice, issuing ultrasonic squeaks of the kind that males emit to show lurve.
The behavior was not all-male, though. The engineered mice mated with males in a female-typical manner. And, unlike normal males, they did not attack other males.
But when their babies were born, they again became like feckless males, insouciant about raising their offspring and keen on having more sex.
Usually, female mice spend around 80 percent of their time in their nest nursing their newborns and while lactating will attack male intruders and reject any attempt at a cuddle.
But, for the mutant mother mice, it was party time.
Just two days after giving birth, they started to wander away from the nest and eventually abandoned the babies altogether -- and when a male showed up, they were docile and receptive to courtship.
"These results are flabbergasting," said Catherine Dulac, a professor of molecular and cellular biology at Harvard University and a researcher with the Howard Hughes Medical Institute, who led the work. "Nobody had imagined that a simple [genetic] mutation like this could induce females to behave so thoroughly like males."
To check whether there could be any factors in the mutant mice that could induce this dramatic behavior change, the scientists surgically removed the vomeronasal organs from the noses of normal female mice -- and the same thing happened.
The findings are important, because they amount to a massive blow to those who for decades have looked for underlying differences in brain structure to explain why sexual behavior between males and females is so dissimilar.
The answer appears to be this: in the mice at least, there is no difference. The hard-wiring of the brains is the same.
"In the big picture, it suggests that the female brain has a perfectly functional male behavior circuit" which is repressed by signals from the vomeronasal organ, said Dulac.
Seen from the perspective of developmental biology, "the finding is very satisfactory," she said.
"It means you only have to build one brain in a species and that the one brain is built, more or less, the same in the male and female," she said.
The results do not apply directly to humans, as we and other higher primates lack a vomeronasal organ. But they may open up new paths of investigation into gender-specific human behavior.
FOX HUNT: To suppress dissent, Chinese living abroad that Xi Jinping sees as threats are told to either return to China or commit suicide, Christopher Wray said Chinese agents have been pursuing hundreds of Chinese nationals living in the US in an effort to force their return, as part of a global campaign against the country’s diaspora, known as Operation Fox Hunt, FBI Director Christopher Wray said on Tuesday. In a speech about the security threat posed by China, during which he said Beijing’s counterintelligence work was the “greatest long-term threat to our nation’s information and intellectual property, and to our economic vitality,” Wray gave the example of one Fox Hunt target who was given a choice of going back to China or killing themselves. Fox Hunt was launched
INTERNET CURBS: People are rushing to erase their digital footprints after police given powers over online activity, although it might take years for the full effect to be felt At midnight on Tuesday, the Great Firewall of China, the vast apparatus that limits the country’s Internet, appeared to descend on Hong Kong. Unveiling expanded police powers as part of contentious new national security legislation, the Hong Kong government enabled police to censor online speech, and force Internet service providers to hand over user information and shut down platforms. Many residents, already anxious since the legislation took effect last week, rushed to erase their digital footprint of any signs of dissent or support for the past year of protests. Hong Kong Legislator Charles Mok (莫乃光), a pro-democracy member of the Legislative
‘FIGHT FOR FREEDOM’: Hong Kongers will never bow to Beijing, the advocate said, while the US’ envoy to the territory called China’s new security law a ‘tragedy’ The world must stand in solidarity with Hong Kongers after Beijing imposed sweeping national security legislation on the semi-autonomous territory, advocate Joshua Wong (黃之鋒) said yesterday, vowing to continue campaigning for democracy. Wong, one of the territory’s most prominent young advocates and a figure loathed by Beijing, was speaking outside a court where he and fellow advocates are being prosecuted for involvement in last year’s pro-democracy protests. China last week enacted sweeping security legislation for the restless territory, banning acts of subversion, secession, terrorism and collusion with foreign forces. The legislation has sent a wave of fear through the territory, and criminalized dissenting
‘SUICIDE’: Media reports said Park Won-soon went missing on Thursday after a staff member filed a sexual harassment claim against him this week Seoul mayor Park Won-soon, viewed as a potential candidate for the 2022 presidential election, was found dead of an apparent suicide hours after he was reported missing, police said, adding that he was the subject of an undisclosed investigation. In a note he is thought to have left behind on his desk, Park offered his apologies. “I thank everyone who was with me in my life. I apologize to my family for only making them suffer from pain,” according to the note that was released by his office yesterday. Park, in his letter, asked to be cremated and have his remains spread