frigate.book

https://big5.backchina.com/?236905

成功女性都隱藏著一個男性大腦？

作者：frigate.book 於 2007-8-22 23:38 發表於最熱鬧的華人社交網路--貝殼村

作者分類:science nature|通用分類:其它日誌

天氣: 陰雨

心情: 平靜

離子通道，trpc2基因敲除鼠,雌性鼠表現雄性行為特徵。
沒有男性/女性的大腦
只有男性/女性的鼻子
因為鼻子接受不同的信息，從而刺激大腦產生不同男性/女性行為

First this week, news that will shock feminists everywhere because it looks like there is a male mind lurking inside every female, at least in mice. Catherine Dulac told Kerri Smith how on activating a single gene can turn sedate females into sex-craze man-eaters. Nature advance online publication 5 August 2007

Catherine Dulac: Everyone observing animal behaviour knows that the biggest difference in individual behaviour is between males and females. So, these comprise productive behaviour, maternal behaviour, social behaviour, very large array of different behaviours. And so people for many many years have been looking at the brain and tried to identify what is the nerve origin of these behavioural differences between males and females. To everybody's surprise those differences have been extremely minor and so we observed the behaviour of a mutant mouse that is affected for a gene called Trpc2, which encode an ion channel that is required for a sensory organ called the vomeronasal organ to function. And astonishingly the female mouse then behaves exactly like a male and so that tells us that within the female brain exists a perfectly functional male behaviour circuits and that the circuit is actually repressed in the normal animal. So, the male and female brains are probably very similar in nature and that is why people did not see those distinct differences and what makes male and female behave differently are sensory input that makes sure that the right gender behaviour is activated and wrong one is repressed.

Kerri Smith: Let us go back to this gender behaviour then. How do you mean they act like males?

Catherine Dulac: They act like a male in two types of behaviours, one is sexual behaviour. So, basically the female attempts to mount other mice exactly like male. They have pelvic thrust exactly like male. You would see the video of these mice. You would not be able to distinguish from a behavioural point of view, the behaviour of these mutant female to the behaviour of a genuine male. So, the sexual behaviour is identical to that of a male and what we call the courtship behaviour is also the one of a male. So, the courtship behaviour if you wish is the way a male normally approaches a female. It raises its snout and over the body of the female it made ultrasound vocalization typically and very specifically to a female. So, all these very male-specific traits are all shown and displayed by the mutant female.

Kerri Smith: And this is the doing of just one mutant gene then, this Trpc2 gene that you were telling us about. What does this gene do when it is working normally?

Catherine Dulac: It is essential for the sensory function of a set of olfactory neurons that are located on the tip of the nose in a structure called vomeronasal organ. In rodents and in animals that have a functional vomeronasal organ, this structure was thought to be essential for detecting pheromones. Pheromones are chemicals that are used among animals to communicate with each other to provide social cues. In the male, we have found that it is essential for sex discrimination so for an animal to be able to tell apart a male from a female and our story that we are publishing now shows that in the female it is also essential to ensure that the female behaves like a female.

Kerri Smith: Now, that was going to be my next question. You have found that female mice with these Trpc2 mutations, or would have their vomeronasal organs removed acted just like males, is the reverse true that males with this mutation act like females?

Catherine Dulac: We already know that the Trpc2 mutant males are much less aggressive. So, you could say this could be a trait that resembled that of a female, but overall, you know, I think the expectation is that, it is very likely that what we found in the female also exists in the male because from a developmental point of view it makes total sense. Instead of building a male brain and then the female brain, you build a mouse brain and then there is a sensory switch that makes sure that the animal behaves appropriately according to its gender. So, what we found in the female presumably also exists in the male.

Chris Smith: And I have heard there is a human homologue for that knock out. It is called alcohol and going to university. Harvard's Catherine Dulac has found how to de-repress the circuits for male behaviour in the brains of female mice.

http://www.nature.com/nature/podcast/v448/n7154/nature-2007-08-09.html