研究發(fā)現(xiàn)，女性的卵子會在受孕的最后時刻選擇幸運的精子

研究發(fā)現(xiàn)，女性的卵子會在受孕的最后時刻選擇幸運的精子

In females, for example, hormones present at ovulation can drive a woman to choose a cocky, confident man with a slight stubble and more masculine features. Men can sniff out an ovulating woman just by smelling her T-shirt, while women appear to prefer the smell of a man with dissimilar genes, which could give her offspring a boost up the evolutionary ladder.

對于女性來說，排卵時的荷爾蒙會促使她們選擇一個有一點胡茬、更男性化的驕傲自信的男人。男人可以通過聞她的t恤來嗅出正在排卵期的女人，而女人似乎更喜歡具有不同基因的男人的氣味，這可能會給她的后代提供一個進化階梯。

A fascinating new study finds those chemical-based preferences continue even after sex.

一項引人注目的新研究發(fā)現(xiàn)，這些基于化學(xué)物質(zhì)的偏好甚至在性行為之后依然存在。

Human eggs appear to "choose" which sperm will become the lucky winner in conceiving a baby.

人類卵子似乎會“選擇”哪一個精子將成為懷孕的幸運贏家。

"Human eggs release chemicals called chemoattractants, which leave a sort of chemical breadcrumb trail that sperm use to find unfertilized eggs," said study author John Fitzpatrick, an assistantprofessor in the department of zoology at Stockholm University in Sweden.

“人類卵子會釋放一種叫做化學(xué)引誘劑的化學(xué)物質(zhì)，這種化學(xué)物質(zhì)會留下一種類似面包屑的痕跡，精子會利用這種痕跡來尋找未受精的卵子，”研究作者、瑞典斯德哥爾摩大學(xué)動物學(xué)系助理教授約翰·菲茨帕特里克說。

"What we didn't know until this study is those chemical breadcrumbs act differently on sperm from different males, in effect choosing which sperm is successful," Fitzpatrick added.

菲茨帕特里克補充道:“在這項研究之前，我們不知道這些化學(xué)物質(zhì)對不同雄性精子的作用是不同的，它們會影響選擇成功的精子。”

"What this is suggesting is that these fluids are giving females one extra chance — long after she's picked her partner — to bias the number of sperm that are going to be coming towards the eggs."

“這表明，這些液體給了雌性一個額外的機會——在她選擇了伴侶很久之后——來改變向卵子靠近的精子數(shù)量。”

The hunt for diverse genes

尋找不同的基因

What makes a partner genetically compatible? One of the driving factors for that, Fitzpatrick said, are a complex set of genes called the "major histocompatibility complex," or MHC for short.

是什么讓一個伴侶在基因上兼容? 菲茨帕特里克說，其中一個驅(qū)動因素是一組被稱為“主要組織相容性復(fù)合體”(MHC)的復(fù)雜基因。

"Basically what these genes are about is fighting infection, fighting diseases and helping our immune system do really well," he said. "The more diverse those genes are, the more diverse are the kinds of infections you can fight.

他說:“基本上，這些基因的作用就是抵抗感染，抵抗疾病，幫助我們的免疫系統(tǒng)發(fā)揮作用。”“這些基因越多樣化，你能對抗的感染就越多樣化。

And if your partner has a slightly different combination of these genes than you do, then you're going to produce offspring that can fight an even broader array of pathogens and diseases."

如果你的伴侶的這些基因組合與你略有不同，那么你的后代將能夠?qū)垢鼜V泛的病原體和疾病。”

And because mammals, including humans, are programmed to give our offspring the best chance for survival, our bodies have developed all sorts of methods to reward the strongest, most diverse and compatible mate possible.

因為哺乳動物，包括人類，都是為了給后代最好的生存機會而設(shè)計的，我們的身體已經(jīng)發(fā)展出各種方法來獎勵最強壯、最多樣化和最兼容的配偶。

Even the female reproductive tract is an obstacle course designed to weed out weaker, less acceptable suitors.

甚至雌性的生殖道也是一個障礙通道，旨在淘汰較弱的、不太受歡迎的追求者。

Reproductive tract fluids, for example, flow downwards, thus forcing sperm to swim upstream, much like salmon must do when they spawn. At the same time, Fitzgerald said, the female's immune system views sperm as a foreign invader, attacking those swimmers as if they were germs.

例如，生殖道的液體向下流動，從而迫使精子逆流而上，就像鮭魚產(chǎn)卵時必須做的那樣。菲茨杰拉德說，與此同時，雌性的免疫系統(tǒng)將精子視為外來入侵者，將那些游泳者當(dāng)成細菌來攻擊。

Once past the obstacle of the cervix's muscular contractions, sperm must then choose and swim up one of two fallopian tubes — yet the egg only travels down one, leaving a "blind alley that they can go down where there's no payoff."

一旦通過了宮頸肌肉收縮的障礙，精子就必須選擇并游上兩根輸卵管中的一根——然而卵子朝一根游下去，留下了一條“沒有回報的死胡同”。