1.Jambo, bonjour, zdraveite, trayo: these are a few of the languages that I’ve spoken little bits of over the course of the last six weeks.
Jambo, bonjour, zdraveite, trayo。这些是几种不同的语言， 我在过去六周里多多少少用到了它们。
2.As I’ve been to 17 countries I think I’m up to on this crazy tour I’ve been doing, checking out various aspects of the project that we’re doing,
我在进行一个非常疯狂的旅行，总共要跑十七个国家， 去为我们正在做的项目做各种各样的事。
3.and I’m going to tell you a little bit about later on.
我现在就要向你们介绍这个项目。
4.And visiting some pretty incredible places.
我也见到了各种绝妙的风土人情。
5.Places like Mongolia, Cambodia, New Guinea, South Africa, Tanzania twice; I was here a month ago.
像是蒙古，柬埔寨，新几内亚，南非，我还来过两次坦桑尼亚。 一个月前来过一次。
6.And the opportunity to make a whirlwind tour of the world like that is utterly amazing, for lots of reasons.
这种旋风式的全球旅行的机会 是绝妙十足的，原因很多，
7.You see some incredible stuff.
（首先）你能长不少见识，
8.And you get to make these spot comparisons between people all around the globe.
同时你还能比较不同的地区， 比较全球的人种。
9.And the thing that you really take away from that, the kind of surface thing that you take away from it, is not that we’re all one, although I’m going to tell you about that,
最重要的是你意识到， 那种最明显的感觉就是， 并不是我们又多么像一个整体，尽管我想和你们讨论这方面。
10.but rather how different we are.
而是我们彼此有多么的不同。
11.There is so much diversity around the globe.
放眼全球多种多样的人，
12.6,000 different languages, spoken by six and a half billion people, all different colors, shapes, sizes.
六十五亿人口，不同肤色，不同高矮胖瘦， 讲着六千种不同的语言。
13.You walk down the street in any big city, you travel like that, and you are amazed at the diversity in the human species.
当你做这样的旅行，当你在任何大城市的大街上漫步， 你会被人类的多样性所惊服。
14.How do we explain that diversity?
怎样解释这种多样性呢？
15.Well, that’s what I’m going to talk about today, is how we’re using the tools of genetics, population genetics in particular, to tell us how we generated this diversity,
这正是我今天要讲的。 就是我们怎样用遗传学的方法， 特别是人口遗传学，来说明我们是怎么进化出多样性的，
16.and how long it took.
还有花了多长时间产生多样性的。
17.Now, the problem of human diversity, like all big scientific questions, how do you explain something like that, can be broken down into sub questions.
现在，人类多样性的问题， 就像是所有那些重要的科学问题， 很难一下子说清楚。 我们可以把这个大问题分解成一些小问题，
18.And you can ferret away at those little sub questions.
然后你就能一个个地解决。
19.First one is really a question of origins.
第一个小问题其实是关于人类的起源。
20.Do we all share a common origin, in fact?
我们到底是不是从同一个起点来的？
21.And given that we do, and that’s the assumption everybody, I think, in this room, would make — when was that?
如果是的话，这也是每个人都赞同的假说， 又是在什么时候？
22.When did we originate as a species?
从什么时候我们作为一个物种开始存在？
23.How long have we been divergent from each other?
我们已经（从一个起源）开始分支了多长时间？
24.And the second question is related, but slightly different.
第二个小问题和这个有关，但是很不一样。
25.If we do spring from a common source, how did we come to occupy every corner of the globe, and in the process generate all of this diversity,
那就是如果我们都是从一个起点来的， 又是怎样散布到世界的各个角落， 怎样一步步产生不同的人种，
26.the different ways of life, the different appearances, the different languages around the world.
不同的生活方式，不同的样貌， 不同的语言的呢？
27.Well, the question of origins, as with so many other questions in biology, seems to have been answered by Darwin over a century ago.
关于起源的问题，就像很多其他生物学上的问题一样， 看起来已经被达尔文在一百年前就回答了。
28.In The Descent of Man, he wrote, “In each great region of the world the living mammals are closely related to the extinct species of the same region.
在他的书“人类的起源”中，他写道： “在世界的每个区域，现存的哺乳动物 都和同一区域灭绝的物种紧密相连。
29.It’s therefore probable that Africa was formerly inhabited by extinct apes, closely allied to the gorilla and chimpanzee.
因此很有可能非洲从前有类人猿，现在灭绝了， 而它们和大猩猩以及黑猩猩相关。
30.And as these two species are now man’s nearest allies, it’s somewhat more probable that our early progenitors lived on the African continent, than elsewhere.”
这两个物种是现今人类的最接近的物种， 由此可见，人类的早期祖先 最有可能生活在非洲大陆上，而不是别处。”
31.So we’re done, we can go home, finished the origin question.
这样问题就解决了，我们可以回家了，我们回答了起源的问题。
32.Well, not quite. Because Darwin was talking about our distant ancestry, our common ancestry with apes.
等等，并没有完全回答。因为达尔文讲的是我们的远祖， 我们和猿类共享的始祖。
33.And it is quite clear that apes originated on the African continent.
很明显猿类是从非洲大陆来的。
34.Around 23 million years ago they appear in the fossil record.
根据化石记载它们是在两百三十万年前出现的。
35.Africa was actually disconnected from the other land masses at that time, due to the vagaries of plate tectonics, floating around the Indian Ocean.
非洲已经和其他大陆分隔开了。 由于捉摸不定的的板块构造，非洲在印度洋上漂浮，
36.Bumped into Eurasia around 16 million years ago, and then we had the first African exodus, as we call it.
大约一百六十万年前，撞到欧亚板块上， 我们就有了第一次的所谓的“非洲物种外流”。
37.The apes that left at that time ended up in Southeast Asia, became the gibbons and orangutans.
那时候离开非洲的猿类到达了东南亚， 演变成了长臂猿和猩猩。
38.And the ones that stayed on in Africa evolved into the gorillas, the chimpanzees and us.
那些留在非洲的猿类 演变成了大猩猩，黑猩猩，和我们人类。
39.So yes, if you’re talking about our common ancestry with apes it’s very clear by looking at the fossil record, we started off here.
所以，如果你指的是我们和猿类的共同祖先， 只要看化石纪录，毫无疑义地，我们是从非洲来的。
40.But that’s not really the question I’m asking.
但是这并不是我想知道的问题。
41.I’m asking about our human ancestry, things that we would recognize as being like us if they were sitting here in the room.
我指的是原始人类， 从它们变成为人类开始算， 就好像是原始人类现在就在这个房间，
42.If they were peering over your shoulder, you wouldn’t leap back like that. What about our human ancestry?
如果它们就在你边上， 你不会吓得往后退。什么是原始人类？
43.Because if we go far enough back, we share a common ancestry with every living thing on Earth.
如果我们追溯起源。 我们能够找到和世界上所有生命的共同起源。
44.DNA ties us all together, so we share ancestry with barracuda, bacteria and mushrooms, if you go far enough back, over a billion years.
DNA把我们联系起来，我们甚至和梭鱼， 细菌，蘑菇，都有共同祖先，如果你真的是往回找上十亿年的话。
45.What we’re asking about though is human ancestry.
我们这里讲的是原始的人类祖先。
46.How do we study that?
怎么研究呢？
47.Well, historically it has been studied using the science of paeleoanthropology, digging things up out of the ground, and largely on the basis of morphology,
古生人类学已经研究了很多年了， 他们挖掘古生物遗迹， 大部分的分类是根据样貌，
48.the way things are shaped, often skull shape, saying, “This looks a little bit more like us than that, so this must be my ancestor.
古生物是什么样子的，多数是根据头骨的样子，好比说 “这个比那个看起来更像我们一点点，那么这个想必是我的祖先。
49.This must be who I’m directly descended from.”
我想必是从这个起源演化来的。”
50.The field of paeleoanthropology, I’ll argue, gives us lots of fascinating possibilities about our ancestry, but it doesn’t give us the probabilities that we really want as scientists.
我得说，古生人类学 向我们提供了很多非常有价值的可能性， 但是没有给我们提供每种可能性的概率，那才是科学家们真正需要的。
51.What do I mean by that?
怎么说呢？
52.You’re looking at a great example here.
这里是个很好的例子：
53.These are three extinct species of hominids, potential human ancestors.
三个灭绝了的原始人种， 每个都可能是人类的祖先。
54.All dug up just west of here in Olduvai Gorge by the Leakey family.
它们都是在 Olduvai Gorge 以西被 Leakey 家族发掘的。
55.And they’re all dating to roughly the same time.
它们也都是从差不多同一个时期来的。
56.From left to right we’ve got Homo erectus, Homo habilis, and Australopithecus — now called Paranthropus boisei, the robust australopithecine. Three extinct species, same place, same time.
从左到右，我们有直立人，能人 和南方古猿 — 现在叫做鲍氏傍人的， 也就是更新世灵长类动物。三个已经灭绝的物种，存在于同一个空间，同一个时间。
57.That means that not all three could be my direct ancestor.
这说明不可能每一个都是我们的祖先。
58.Which one of these guys am I actually related to?
到底哪一个是呢？
59.Possibilities about our ancestry, but not the probabilities that we’re really looking for.
都有可能性，但是我们要看的是哪个机率更大。
60.Well, a different approach has been to look at morphology in humans using the only data that people really had at hand until quite recently —
另一个方法是看人体形态 这也是最近才有的方法 —
61.again, largely skull shape.
大部分是靠头骨的形状。
62.The first person to do this systematically was Linnaeus, Carl von Linne, a Swedish botanist, who in the 18th century took it upon himself
第一个系统地做这件事的人叫 Linnaeus， Carl von Linne， 是个瑞士植物学家， 十八世纪的人，自己一个人
63.to categorize every living organism on the planet.
把地球上所有存在的生物分了类。
64.You think you’ve got a tough job?
你还抱怨你的工作难做么？
65.And he did a pretty good job.
他还做得很不错。
66.He categorized about 12,000 species in Systema Naturae.
他把大约一万两千种不同的物种分了类。
67.He actually coined the term Homo sapiens — it means wise man in Latin.
还创造了“智人”这个名词 — 拉丁文中的意思是“有智慧的人”。
68.But looking around the world at the diversity of humans, he said, “Well, you know, we seem to come in discreet sub-species or categories.”
但是看看世界上那么多不同的人种，他说： “你知道，我们看起来是差别细微的亚种，或者只是不同类的智人。”
69.And he talked about Africans and Americans and Asians and Europeans, and a blatantly racist category he termed monstrosus, which basically included all the people he didn’t like,
他提到了非洲人，美洲人，亚洲人和欧洲人， 也公然地把所有他不喜欢的人种 一古脑儿归类成 “monstrosus”，
70.including imaginary folk like elves.
其中还包括了想象中的人物，比如精灵。
71.It’s easy to dismiss this as the perhaps well-intentioned, but ultimately benighted musings of an 18th century scientist working in the pre-Darwinian era.
我们很容易对这个结果嗤之以鼻， 虽然这个研究的意图是好的， 毕竟这是达尔文出现前十八世纪的比较愚昧的研究。
72.Except, if you had taken physical anthropology as recently as 20 or 30 years ago, in many cases you would have learned basically that same classification of humanity.
不过，如果你去上人类学的课， 大概二三十年前， 很多时候你还是学的同样的人类分类法呢。
73.Human races that according to physical anthropologists of 30, 40 years ago — Carlton Coon is the best example — had been diverging from each other — this was in the post-Darwinian era —
人类种族，在三四十年前的人类学家来看 — Carlton Coon 是最好的例子 — 从直立人时代以来，已经相互分离了 — 这已经是后达尔文时代了 —
74.for over a million years since the time of Homo erectus.
一百万年还不止。
75.But based on what data?
但是有什么证据呢？
76.Very little. Very little. Morphology and a lot of guesswork.
很少，几乎没有。形态学和很多猜想而已。
77.Well, what I’m going to talk about today, what I’m going to talk about now, is a new approach to this problem.
我今天要介绍给大家的。 现在要讲的，是一个全新的研究方法。
78.Instead of going out and guessing about our ancestry, digging things up out of the ground, possible ancestors, and saying it on the basis of morphology,
不是光靠出去满处挖掘， 猜想谁是你可能的祖先， 就靠着谁长得像，
79.which we still don’t completely understand.
更别提我们还不太明白怎么确定谁长得像呢。
80.We don’t know the genetic causes underlying this morphological variation.
因为我们并不完全理解基因变异怎么导致了形态的改变。
81.What we need to do is turn the problem on its head.
我们要做的是变被动为主动，
82.Because what we’re really asking is a genealogical problem.
因为说到底这是一个家谱的研究。
83.Or a genealogical question.
或者说是家谱问题。
84.What we’re trying to do is construct a family tree for everybody alive today.
我们试图做的是给每个人画一个家谱，
85.And as any genealogist will tell you — anybody have a member of the family, or maybe you, have tried to construct a family tree, trace back in time?
就像家谱学家对你说的 — 有没有谁家族里有人，或者就是你自己， 试图追根溯源，画出家谱的？
86.You start in the present with relationships you’re certain about.
你从确信对的亲属关系开始，
87.You and your siblings, you have a parent in common.
你和你的兄弟姐妹，同样的父母，
88.You and your cousins share a grandparent in common.
然后加上你的表亲，你们的祖父母是相同的。
89.You gradually trace further and further back into the past, adding these ever more distant relationships.
你渐渐回溯到越来越早， 加上更多的远亲。
90.But eventually, no matter how good you are at digging up the church records, and all that stuff, you hit what the genealogists call a brick wall.
但是最终，不管你有多么能干，发掘了教堂的记载， 所有的来源，你还是会遇到一个家谱学家所说的“碰壁”。
91.A point beyond which you don’t know anything else about your ancestors, and you enter this dark and mysterious realm we call history,
也就是你实在找不出更多的信息了。 你会陷入历史的迷雾，
92.that we have to feel our way through with whispered guidance.
只能靠着细小的声音找寻出路。
93.Who were these people who came before?
这些人是谁？谁先谁后？
94.We have no written record. Well, actually we do.
我们没有纸上记载。事实上，我们有记录保存下来。
95.Written in our DNA, in our genetic code.
信息都记在我们的DNA里，在我们的基因书中。
96.We have an historical document that takes us back in time to the very earliest days of our species. And that’s what we study.
就像一本历史长卷，把我们带回过去， 带到我们人种最早的年代去。这就是我们要研究的。
97.Now, a quick primer on DNA.
现在，简单介绍一下DNA。
98.I suspect that not everybody in the audience is a geneticist.
我猜不是每个听众都是遗传学家。
99.It is a very long, linear molecule, a coded version of how to make another copy of you. It’s your blueprint.
DNA是个非常长的线状物，一个如何复制你自己的密码书， 也是你的蓝图。
100.It’s composed of four subunits: A, C, G and T, we call them.
DNA有四个成分组成：A，C，G和T。
101.And it’s the sequence of those subunits that defines that blueprint.
这四个成分的组合顺序决定了蓝图，
102.How long is it? Well, it’s billions of these subunits in length.
DNA有多长？有上百亿个成分组成。
103.A haploid genome. We actually have two copies of all of our chromosomes.
我们的基因是双份的，我们的染色体有一式两份，
104.A haploid genome is around 3.2 billion nucleotides in length.
每份基因有三十二亿核酸那么长，
105.And the whole thing, if you add it all together, is over six billion nucleotides long.
如果你把所有的染色体连起来， 就有多于六十亿核酸长。
106.If you take all the DNA out of one cell in your body and stretch it end to end, it’s around two meters long.
如果你把你体内一个细胞的DNA拿出来， 头尾相连，大概是两米长。
107.If you take all the DNA out of every cell in your body and you stretch it end to end, it would reach from here to the moon and back,
如果你把你体内每一个细胞的DNA都拿出来， 头尾相连，可以从地球到月球再回来，
108.thousands of times. It’s a lot of information.
往返成千上万次。这里包含了很多的信息。
109.And so when you’re copying this DNA molecule to pass it on, it’s a pretty tough job.
当你复制这些DNA时，试图把信息传到下一代时，是个很难的工作。
110.Imagine the longest book you can think of, War and Peace.
想象你知道得最长的书，比如战争与和平，
111.Now multiply it by 100.
乘上一百倍，
112.And imagine copying that by hand.
然后想象你手抄这些书，
113.And you’re working away until late at night, and you’re very, very careful, and you’re drinking coffee and you’re paying attention, but occasionally,
直到深夜， 你非常非常小心，喝咖啡保持清醒， 你注意力高度集中，但是时不时地，
114.when you’re copying this by hand, you’re going to make a little typo — a spelling mistake.
当你手抄的时候， 还是会出错 — 抄错字母。
115.Substitute an I for an E, or a C for a T.
本来是 I 写成了 E，本来是 C 写成了 T。
116.Same thing happens to our DNA as it’s being passed on through the generations.
这种事情在DNA复制的时候也会发生。
117.It doesn’t happen very often. We have a proofreading mechanism built in.
不常发生，因为我们有查错和纠错的系统，
118.But when it does happen and these changes get transmitted down through the generations, they become markers of descent.
但是一旦发生了，这些改变会传到下一代， 刚好变成了世代相传的标签。
119.If you share a marker with someone, it means you share an ancestor at some point in the past.
如果你和别人有一个相同标签， 这说明你们血脉相连。
120.The person who first had that change in their DNA.
都能连回到那个第一次产生这个标签的人。
121.And it’s by looking at the pattern of genetic variation, the pattern of these markers in people all over the world, and assessing the relative ages when they occurred throughout our history,
通过观察基因变异的类型， 全世界人们携带的标签的类型， 来分析标签产生的年代，
122.that we’ve been able to construct a family tree for everybody alive today.
正是我们用来给每个人创造家谱的方法。
暂无讨论，说说你的看法吧
