研究表明女性基因其實更“強勢”

While women have for centuries been labelled as the weaker sex, new research suggests the truth is quite the opposite。

According to a study, the fairer sex is genetically programmed to better resist infections and cancer, and also have a back-up system for fighting disease。

The discovery sheds light on why members of the so-called stronger sex succumb to "man-flu"。

The reason why women are more robust appears to be microRNAs - short strands of RNA encoded on the chromosome, scientists believe. RNA is a genetic cousin of DNA and can have important biological effects。

The microRNAs have the effect of "silencing" immunity genes on X-chromosome, according to the new research. This leaves men at a disadvantage since they only have one X chromosome. Women have two, so that even when immunity genes are silenced on one the other can compensate. So man's immune systems are no match for those of wives and girlfriends

Study leader Dr Claude Libert, from Ghent University in Belgium, said: "Statistics show that in humans, as with other mammals, females live longer than males and are more able to fight off shock episodes from sepsis, infection or trauma. We believe this is due to the X chromosome. "

From a biological point of view, the difference has probably evolved because women are more likely to ensure the survival of the species. They need to be able to resist infection when pregnant and when nuturing a child。

The research is published today in the journal BioEssays。據英國《每日電訊報》9月28日報道，幾世紀以來，女性都被打上弱勢性別的標籤，但一項新研究表明，事實可能正好相反。

根據該研究，女性基因更能有效抵抗傳染病和癌症，同時其基因還具備一套抵禦疾病的支持體系。

這一發現解釋了所謂的強勢性別——男人總易患流感的原因。

科學家認爲，女性更健康的原因可能在於微RNA(核糖核酸)，它是染色體上RNA編碼的短片段。而RNA是DNA(脫氧核糖核酸)的基因表親，具有重要的生物學效應。

根據這項新研究，微RNA具有“屏蔽”X染色上的免疫基因的效果。這使只有一條X染色體的男性處於不利地位，而女性擁有兩條，所以即使一條上的免疫基因不能發揮作用，另一條上的也能起到彌補作用。所以，男性的免疫系統無法與他們妻子和女朋友的匹敵。

來自比利時根特大學的研究領導者克勞德•力博特博士說：“數據表明，在人類和其他哺乳動物中，女性壽命更長，更能抵禦因敗血症發作引起的休克、感染病和創傷。我們認爲這可以歸因於X染色體。”

從生物學角度來說，這種差異的演化可能是出於女性更有可能確保種族生存。她們需要在懷孕和養育子女的時具備抵禦傳染的能力。

該研究發表在今日(28日)的《生物》雜誌上。