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Sex is fun, right? But, what if it wasn't?
啪啪啪很好玩儿，对吧？但是，如果不好玩儿呢？
Finding a partner, maintaining a long-term partnership and procreating at the right time, all that is very difficult.
找个对象，维持长期的恋爱关系，然后在恰当的时间为爱鼓掌是很难的。
Wouldn't it be better to just… make another me?
那何不直接……再制造一个我呢？
Everyone, thank you for watching dnews today, I'm trace.
大家好。感谢大家收看今天的dnews，我是Trace。
Six years ago, biologists discovered the Mycocepurus smithii, a species of ant which are ALL female; they're asexual.
六年前，生物学家们发现了一种学名为Mycocepurus smithii的蚂蚁，这是一种全是雌性的蚂蚁，因为它们的生殖方式为无性繁殖。
The queen clones herself and if the eggs go unfertilized they'll all hatch female.
蚁后能够进行自我克隆，如果产下的卵没有受精，就会孵化出雌性蚂蚁。
Bonus, they then have a whole host of awesome new ants!
接着它们就有了一窝漂亮的新成员了！惊不惊喜，意不意外！
Sexuality is a lot of work,
既然啪啪啪这么麻烦，
while asexual reproduction is exceedingly efficient (if kind of less fun), and sexual dimorphism, or splitting into a binary sex pair, limits the species… doesn't it?
无性繁殖又那么有效（虽然不那么有趣），性别二态性，或分裂成二元性对，又会限制物种的发展......难道不会吗？
Why do we have sex?
那我们为什么还要啪啪啪呢？
Aside from the pleasurable feelings associated with sex, lowering of stress, strengthening of romantic bonds and so on and so on
我是说除了性爱能够带来愉悦，能够减压，能够促进两人的恋爱关系等等这些好处之外
Those things are evolution's way of GETTING US to HAVE sex.
那些好处都是演化为了让我们进行这项运动而赋予它的。
That's not what I mean.
并不是我真正想讨论的内容。
You could say, the WHY is easy,
你可以说，原因很简单，
we have sex to reproduce; sex equals passing on genes and a promise of success!
我们啪啪啪是为了繁衍后代啊；啪啪啪就就意味着传递基因，以及传递成功的可能性啊！
But that's STILL not what I’m trying to get to.
但这还！是！不是我们想问大家的问题。
Like, why, man? The Smithii doesn't get busy! She's ASEXUAL. She just… clones herself.
我想问的是，Smithii蚂蚁不需要为了性爱忙得团团转，因为它是无性爱的物种，她可以直接……克隆自己。
BIOLOGICALLY speaking, WHY sex?
所以，从生物学的角度来说，我们为什么要啪啪啪呢？
The question “why we have sex at all,” has plagued scientists for decades.
“我们究竟为什么要发生性行为”这一问题已经困扰科学家几十年了。
Some basic theories from the 80s assume the genetic variety is beneficial and sex allows us to purge bad DNA.
80年代的一些基本理论声称遗传多样性是个好东西，而性爱能够让我们淘汰掉那些不好的基因。
A book in the 90s invented The Red Queen hypothesis, named after the character from “Through the Looking Glass.
90年代的一本书提出了“红皇后假设”，这一假设是以《爱丽丝镜中奇遇记》里的同名角色命名的。
This describes sexual evolution like a race.
该假设称，性别的演化就像种族一样。
We're all evolving to combat other organisms' mutations, and by doing so, we stay in balance.
我们都在演化，以对抗其他生物的突变。这样一来，我们就一直处于一种平衡的状态。
Essentially, as parasites and predators evolve, the hosts and prey evolve to survive them, facilitating reproduction.
基本上，随着寄生虫和天敌逐渐演化，宿主和猎物也会演化，从而让自己能够活下去，减轻繁殖的困难。
Of course, having two sexes is pretty inefficient when you look at it this way.
当然了，这么看的话，分两种性别其实是非常影响繁殖效率的。
If I'm in a race to the death, I don't want to have to find a date for Saturday too!
如果我的种族连生存都成了问题，那我也不会有找个对象约会的心思！
They call it the “cost” of men in the book, because we don't necessarily NEED men.
书里面将这一问题称之为有男人的“代价”，因为我们并不真的需要男人。
Or do we? You know, I'm biased here, but I hope we do.
还是说需要呢？我对这个问题我是有偏见的，但我还是希望我们需要男人的。
A new study in Nature Genetics claims to have a scientific way to look at this… sharing our genetic material makes us stronger and better able to fight disease.
《自然-遗传学》期刊发布的一项新的研究声称他们有研究这一问题的科学手段……共享我们的遗传物质能够让我们变得更加强大，更能抵抗疾病。
Using genetic material from the 1,000 Genomes Project, researchers compared genomes from Africans, Asians, Europeans and Canadians of French descent
通过研究1000个基因组项目的遗传物质，研究人员比较了非洲人，亚洲人，欧洲人，法国血统的加拿大人的基因组，
and found some parts of our DNA are rewritten more often than others.
发现我们DNA的某些部分重写的频次比其他部分更高。
When binary species like humans mate,
人类这样存在两种性别的物种在结合时，
they EACH release genetic material that can allow the building blocks of genes and chromosomes to combine and mutate beneficially.
双方都会释放能够让彼此的基因和染色体的组成部分进行有益的结合和变异的遗传物质。
Some mutations help us, while others increase our risk of diseases.
有些突变对我们有利，其他的则会增加我们患病的风险。
The rarely overwritten “coldspots” they refer to in the research, it turns out, is where bad mutations survive.
事实证明，很少重写的“冷区”就是恶性基因突变存活的地方。
But thanks to sex and these mutations, our genetic material “worsens, and then gets better,” and eventually, bad DNA is overwritten.
不过，幸好有了啪啪啪和这些突变，我们的遗传物质才得以“恶化之后又优化”，最终实现恶性基因的重写。
According to a separately published research by the same 1,000 Genomes Project,
根据1000个基因组项目单独发表的一项研究，
each human offspring has 60 genetic mutations, or about one for every 100 million letters of DNA.
每个人类后代身上都会发生60个基因突变，换句话说，大约每1亿个DNA字母中就有一个突变。
Both asexual and sexual organisms mutate,
无性生物和有性生物都会发生变异，
but asexual organism mutations have to be SO GOOD that they overcome the wider population size, fitness, and mutation rate.
但无性生物的突变必须得格外好，才能克服更广泛的种群规模，适应能力和突变率的问题。
It's less likely a single mutated clone will succeed in a colony, versus the constant trial-and-error of all of sexual organisms.
与所有有性生物的不断试错相比，单个突变的克隆在群体中成功的几率很小。
That doesn't mean sexuality is better of course, just means it's another way to get to that same success.
但这并不意味着有性生殖就更好，有性生殖只不过是繁殖成功的另一个手段而已。
Bacteria aren't the only asexual animals, some reptiles, insects, and fish will reproduce without males around just like those ants; so binary sexuality isn't a hard and fast rule.
细菌并不是唯一的无性动物，一些爬行动物，昆虫和鱼类在没有雄性的情况下都能像前面提到的那种蚂蚁那样繁殖；所以二元性别并不是什么硬性规则。
You know, some are longer and seductive, you know what I'm saying? Don't worry about that.
有些不仅长而且很有诱惑力，你懂的。这个我们先不说了。
Why we have sex at all is still a mystery, but this pulls back the curtain just a little.
我们究竟为什么要啪这个问题至今仍然是个谜，但我们今天的讨论算是将这一问题的神秘面纱掀开了那么一丢丢。
And in the end, asexuality might be faster, but sexuality's DNA lottery has it's benefits too!
归根到底，无性繁殖或许速度上更胜一筹，但有性繁殖的DNA突变也有它的好处！
I know you're gonna comment on this one, so maybe you have already started commenting.
我知道你们会评论这期视频的，或许你们已经开始在下面评论了
Why do you think, BIOLOGICALLY, we humans are not asexual?
那你认为，从生物学的角度来讲，我们人为什么不是无性生物呢？
Get down there and talk it out.
赶紧到评论里告诉我们吧。
Thanks for watching dnews today and make sure you sucscribe for more.
感谢大家收看本期dnews视频，记得订阅查看更多内容噢。
