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SvantePaabo_2011G-_我们体内的尼安德特人dna痕迹_
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| What I want to talk to you about is what we can learn from studying the genomes of living people and extinct humans. |
我今天想谈谈 从研究现代人和古人类 基因组的研究中 我们能够学到什么 |
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genomes:n.[遗]基因组(genome复数); extinct:adj.灭绝的,绝种的;熄灭的;vt.使熄灭;
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| But before doing that, |
在此之前 |
| I just briefly want to remind you about what you already know: that our genomes, our genetic material, are stored in almost all cells in our bodies in chromosomes in the form of DNA, which is this famous double-helical molecule . |
我先简短回顾一下你们已有的知识 我们的基因组 基因物质 几乎存在于人体所有细胞的染色体中 由脱氧核糖核酸（DNA）构成 呈双螺旋分子结构 |
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briefly:adv.简要地;简短地;暂时地; remind:v.提醒;使想起; genetic:adj.基因的;遗传学的; chromosomes:n.[遗][细胞][染料]染色体(chromosome的复数形式); molecule:n.[化学]分子;微小颗粒,微粒;
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| And the genetic information is contained in the form of a sequence of four bases abbreviated with the letters A, T, C and G. |
遗传信息 存在于四种脱氧核苷酸 所组成的序列中 这四种脱氧核苷酸分别简称为 A T C G |
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sequence:n.顺序; v.按顺序排列; abbreviated:adj.简短的;小型的;服装超短的;v.缩写;节略(abbreviate的过去分词);
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| And the information is there twice -- one on each strand -- which is important, because when new cells are formed, these strands come apart, new strands are synthesized with the old ones as templates in an almost perfect process . |
信息有两组 每条氢链上各有一组 这很重要 因为 每当新细胞形成 这些氢链会展开 而新的氢链以旧氢链作为模板进行互补配对 这一过程几乎精准无误 |
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strands:n.线; v.搁浅; synthesized:adj.合成的;综合的;v.合成(synthesize的过去分词);综合; templates:n.模板;范本(template的复数);属性单元; process:v.处理;加工;列队行进;n.过程,进行;方法,adj.经过特殊加工(或处理)的;
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| But nothing, of course, in nature is totally perfect, so sometimes an error is made and a wrong letter is built in. |
当然 在自然界中 事事无绝对 错误总有发生的时候 而一旦发生 一个错误的字母就会被编进去 |
| And we can then see the result of such mutations when we compare DNA sequences among us here in the room, for example. |
我们可以等一下会看到 这些突变产生的结果 例如拿在座各位的DNA 序列 进行比对 |
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mutations:n.[遗]突变;变化;转变(mutation的复数形式); compare:v.比较;对比;n.比较; sequences:n.[数][计]序列,顺序;继起的事(sequence的复数形式);
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| If we compare my genome to the genome of you, approximately every 1,200, 1,300 letters will differ between us. |
如果拿我的基因组与你的基因组相比 每1200到1300个字母 就会出现差异 |
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approximately:adv.大约,近似地;近于;
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| And these mutations accumulate approximately as a function of time. |
这些突变像时间一样 不断累积 |
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accumulate:vi.累积;积聚;vt.积攒;
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| So if we add in a chimpanzee here, we will see more differences. |
如果把一只黑猩猩加进来 我们能看到更多差异 |
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chimpanzee:n.[脊椎]黑猩猩;
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| Approximately one letter in a hundred will differ from a chimpanzee. |
大致每100个字母 就会出现差异 |
| And if you're then interested in the history of a piece of DNA, or the whole genome, you can reconstruct the history of the DNA with those differences you observe . |
如果你对一段DNA 或整个基因组的历史感兴趣 你可以通过观察到的这些差异 对DNA的历史进行重组 |
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reconstruct:vt.重建;改造;修复;重现; observe:v.观察;看到;庆祝;监视;
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| And generally we depict our ideas about this history in the form of trees like this. |
我们可以通过这个树状图 来描述这段历史过程 |
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generally:adv.通常;普遍地,一般地; depict:vt.描述;描画;
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| In this case, it's very simple. |
在这里 情况非常简单 |
| The two human DNA sequences go back to a common ancestor quite recently . |
这两个人类的DNA序列 可以追溯到较为近期的一位共同祖先 |
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recently:adv.最近;新近;
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| Farther back is there one shared with chimpanzees . |
而进一步追溯下去 就找到了他们和黑猩猩的共同祖先 |
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chimpanzees:n.[脊椎]黑猩猩(chimpanzee的复数);
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| And because these mutations happen approximately as a function of time, you can transform these differences to estimates of time, where the two humans, typically , |
由于这些突变 多少起到了时间的作用 你可以通过这些差异 来对时间进行预测 这两个人类通常 |
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transform:v.使改变;使改观;使转换;n.[数]变换式;[化]反式; estimates:n.估计;估价;估计的成本;v.估价;估算(estimate的第三人称单数和复数) typically:adv.代表性地;作为特色地;
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| will share a common ancestor about half a million years ago, and with the chimpanzees, it will be in the order of five million years ago. |
在50万年前有共同的祖先 而与黑猩猩 则在500晚年前有共同的祖先 |
| So what has now happened in the last few years is that there are account technologies around that allow you to see many, many pieces of DNA very quickly. |
在过去几年里 由于有了先进的技术 你们能够很快地查看许许多多DNA片段 |
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technologies:n.技术;科技(technology的复数);
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| So we can now, in a matter of hours, determine a whole human genome. |
我们现在能够在短短几个小时里 鉴别出一整个人类基因组 |
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determine:v.决定;确定;测定;查明;形成;影响;裁决;安排;
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| Each of us, of course, contains two human genomes -- one from our mothers and one from our fathers. |
当然 我们每个人都有两个基因组 一个来自母亲 而另一个来自父亲 |
| And they are around three billion such letters long. |
长度约为30亿个字母 |
| And we will find that the two genomes in me, or one genome of mine we want to use, will have about three million differences in the order of that. |
我们会发现 我的两个基因组 或者一个基因组 在这样的排列中 有300万个差异 |
| And what you can then also begin to do is to say, "How are these genetic differences distributed across the world?" |
现在你可以开始 分析这些基因差异 如何分布在世界各地 |
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distributed:adj.分布的;分散的;v.分发;分配;使分布(distribute的过去分词和过去式)
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| And if you do that, you find a certain amount of genetic variation in Africa. |
如果你这么做 你会发现一定数量的基因变异发生在非洲 |
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variation:n.变异;变体;变奏;变种;
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| And if you look outside Africa, you actually find less genetic variation. |
如果你看非洲以外 你找到相对较少的基因变异 |
| This is surprising, of course, because in the order of six to eight times fewer people live in Africa than outside Africa. |
这让人大吃一惊 这是因为非洲以外的人口数量 比非洲的人口多了6至8倍 |
| Yet the people inside Africa have more genetic variation. |
但是非洲人 拥有更多的基因变异 |
| Moreover , almost all these genetic variants we see outside Africa have closely related DNA sequences that you find inside Africa. |
更值得注意的是 几乎所有非洲以外的 基因变异 都与非洲境内的DNA序列 关系非常密切 |
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Moreover:adv.而且;此外; variants:n.[计]变体;变异型(variant的复数);
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| But if you look in Africa, there is a component of the genetic variation that has no close relatives outside. |
但如果你看非洲境内 基因变异的组成 在非洲以外并没有近亲 |
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component:n.成分;部件;组成部分;adj.构成的; relatives:n.亲戚;亲属;同类事物;(relative的复数)
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| So a model to explain this is that a part of the African variation, but not all of it, |
所以这个模式说明 来自非洲的一部分变异 |
| [has] gone out and colonized the rest of the world. |
走出了非洲 走向了世界 |
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colonized:vt.将…开拓为殖民地; vi.开拓殖民地;
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| And together with the methods to date these genetic differences, this has led to the insight that modern humans -- humans that are essentially indistinguishable from you and me -- evolved in Africa, quite recently, between 100 and 200,000 years ago. |
再通过使用追溯这些基因差异的手段 我们得到这样一个结论 即现代人 本质上基本相同的你和我 都是在10万至20万年前 在非洲出现并演进的 |
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insight:n.洞察力;洞悉; essentially:adv.本质上;本来; indistinguishable:adj.不能区别的,不能辨别的;不易察觉的; evolved:v.(使)逐渐形成;进化;进化形成;(evolve的过去分词和过去式)
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| And later, between 100 and 50,000 years ago or so, went out of Africa to colonize the rest of the world. |
之后 在大约10万到5万年前 他们走出了非洲 走向了世界 |
| So what I often like to say is that, from a genomic perspective , we are all Africans. |
我常说 从基因组的层面上看 我们都是非洲人 |
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genomic:adj.基因组的;染色体的; perspective:n.观点;远景;透视图;adj.透视的;
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| We either live inside Africa today, or in quite recent exile . |
现代人要么生活在非洲 要么就是以前从非洲走出来的 |
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exile:n.流放,充军;放逐,被放逐者;流犯;v.放逐,流放;使背井离乡;
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| Another consequence of this recent origin of modern humans is that genetic variants are generally distributed widely in the world, in many places, and they tend to vary as gradients , from a bird's-eye perspective at least. |
现代人近期起源的 另一个结果 是基因变异 在世界上广泛分布 到很多地方 至少从总体上看 基因变异的走势成斜线状 |
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consequence:n.结果;重要性;推论; origin:n.起源;起因;源头;出身; vary:vi.变化;变异;违反;vt.改变;使多样化;变奏; gradients:n.渐变,[数][物]梯度(gradient复数形式);
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| And since there are many genetic variants, and they have different such gradients, this means that if we determine a DNA sequence -- a genome from one individual -- we can quite accurately estimate where that person comes from, provided that its parents or grandparents haven't moved around too much. |
既然存在如此多的基因变异 它们的变化率也不同 这意味着如果我们鉴别出一个DNA序列 即某个人的基因组 我们就可以非常准确地推算出 这个人来自何方 假设这个人的父母或祖父母 基本都留在一个地方 |
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individual:n.个人;有个性的人;adj.单独的;个别的; accurately:adv.精确地,准确地; provided that:如果;条件是;倘若;
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| But does this then mean, as many people tend to think, that there are huge genetic differences between groups of people -- on different continents , for example? |
但是这就意味着 比如说 许多人认为 不同大洲的人 其基因存在巨大差异吗？ |
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continents:n.[地理]大陆,大洲(continent复数);
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| Well we can begin to ask those questions also. |
我们也在问这些问题 |
| There is, for example, a project that's underway to sequence a thousand individuals -- their genomes -- from different parts of the world. |
有一个正在进行的项目 在为一千个人的基因组排序 这些人来自世界各地 |
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underway:adj.进行中的;起步的;航行中的;n.[公路]水底通道; individuals:n.[经]个人;[生物]个体(individual的复数);
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| They've sequenced 185 Africans from two populations in Africa. |
他们为来自非洲的两个种群的 185人进行了基因组排序 |
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sequenced:[数][计]序列;
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| [They've] sequenced approximately equally [as] many people in Europe and in China. |
他们也在欧洲和中国也找了同样多的人 对其基因组进行排序 |
| And we can begin to say how much variance do we find, how many letters that vary in at least one of those individual sequences. |
现在可以说我们找到了多少差异了 也就是其中一个序列 有多少字母是不同的 |
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variance:n.变异;变化;不一致;分歧;[数]方差;
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| And it's a lot: 38 million variable positions. |
这个数字很大 3千8百万个差异 |
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variable:n.变量;可变因素;可变情况;adj.多变的;易变的;变化无常的;可更改的;
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| But we can then ask: Are there any absolute differences between Africans and non-Africans? |
我们会为 非洲人和非非洲人种 是否存在绝对的差异 |
| Perhaps the biggest difference most of us would imagine existed. |
也许我们许多人所认为的 最大差异曾经存在过 |
| And with absolute difference -- and I mean a difference where people inside Africa at a certain position, where all individuals -- 100 percent -- have one letter, and everybody outside Africa has another letter. |
我所谓的 绝对差异是指 当所有非洲人 在基因序列中 某个特定位置上都有同样一个字母 而所有非非洲人种 在这个位置上都有另一个字母 |
| And the answer to that, among those millions of differences, is that there is not a single such position. |
而在这几百万个差异中 没有任何一个位置有这种情况 |
| This may be surprising. |
这听起来不可思议 |
| Maybe a single individual is misclassified or so. |
也许这是因为个别人被分错组了 |
| So we can relax the criterion a bit and say: How many positions do we find where 95 percent of people in Africa have one variant, 95 percent another variant, and the number of that is 12. |
那我们就把标准放松一些 看看我们在95%的非洲人样本中 能够找到多少个这样的位置 一个变量是 95% 另一个变量 我们得到的数字是12 |
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relax:v.放松,休息;松懈,松弛;变从容;休养; criterion:n.(批评判断的)标准;准则;规范;准据;
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| So this is very surprising. |
这真的很神奇 |
| It means that when we look at people and see a person from Africa and a person from Europe or Asia, we cannot, for a single position in the genome with 100 percent accuracy , predict what the person would carry. |
这意味着我们看到 一个来自非洲的人 和一个来自欧洲或亚洲的人 从单个序列位置来看 我们无法 100%准确判断这个人携带的基因组的序列 |
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accuracy:n.[数]精确度,准确性; predict:v.预报;预言;预告;
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| And only for 12 positions can we hope to be 95 percent right. |
而通过12个序列位置判断 我们也只能期望95%的准确率 |
| This may be surprising, because we can, of course, look at these people and quite easily say where they or their ancestors came from. |
这令人意外 我们从外表上看 很容易就知道他们或其祖先从哪里来 |
| So what this means now is that those traits we then look at and so readily see -- facial features, skin color, hair structure -- are not determined by single genes with big effects, |
这意味着 那些显而易见的特征 包括 面部特征 肤色 毛发结构 都不是由单个其重大作用的基因决定的 |
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traits:n.特性,特质,性格(trait的复数); readily:adv.容易地;乐意地;无困难地; facial:adj.面部的,表面的;脸的,面部用的;n.美容,美颜;脸部按摩; structure:n.结构;构造;建筑物;vt.组织;构成;建造; determined:adj.决定了的:v.决定;(determine的过去分词和过去式) genes:n.基因;(gene的复数)
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| but are determined by many different genetic variants that seem to vary in frequency between different parts of the world. |
而是许多不同基因变体共同作用的结果 而在世界不同的地方 这些变体变化呈现不同频率 |
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frequency:n.频率;发生率;重复率;频繁;
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| There is another thing with those traits that we so easily observe in each other that I think is worthwhile to consider, and that is that, in a very literal sense, they're really on the surface of our bodies. |
关于这些特征的另外一点 我们能够不费吹灰之力就能分辨彼此 我认为这点非常值得思考 那就是 这些特征都体现在我们体表 |
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worthwhile:adj.值得做的,值得花时间的; literal:adj.文字的;逐字的;无夸张的;
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| They are what we just said -- facial features, hair structure, skin color. |
这些都是 面部特征 毛发结构 肤色 |
| There are also a number of features that vary between continents like that that have to do with how we metabolize food that we ingest , or that have to do with how our immune systems deal with microbes that try to invade our bodies. |
在食物的新陈代谢方面 以及对抗病菌的 免疫系统方面 不同人种的 相关特征 也有不同 |
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have to do with:与…有关; metabolize:vt.使新陈代谢;使变形;vi.新陈代谢; ingest:vt.摄取;咽下;吸收;接待; immune:adj.免疫的;免于…的,免除的;n.免疫者;免除者; microbes:n.细菌,[微]微生物;微生物类(microbe的复数形式); invade:v.侵犯;侵略;侵袭;干扰;
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| But so those are all parts of our bodies where we very directly interact with our environment, in a direct confrontation , if you like. |
但这些都属于身体特征 直接与环境互动 也可以说是与自然亲密接触 |
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directly:adv.直接地;立即;马上;正好地;坦率地;conj.一…就; interact:v.互相影响;互相作用;n.幕间剧;幕间休息; confrontation:n.对抗;面对;对质;
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| It's easy to imagine how particularly those parts of our bodies were quickly influenced by selection from the environment and shifted frequencies of genes that are involved in them. |
不难想象 身体这些部位 能够很快被自然选择所影响 并改变相关的 基因频率 |
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particularly:adv.特别地,独特地;详细地,具体地;明确地,细致地; influenced:v.影响;对…起作用;支配;左右;(influence的过去分词和过去式) selection:n.选择;选拔;挑选;被挑选的人(或物); shifted:转移;移动(shift的过去式和过去分词); frequencies:n.频率;发生率;重复率;频繁;(frequency的复数) involved:adj.有关的; v.涉及; (involve的过去式和过去分词)
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| But if we look on other parts of our bodies where we don't directly interact with the environment -- our kidneys , our livers , our hearts -- there is no way to say, by just looking at these organs , where in the world they would come from. |
如果我们看看那些 不直接接触外界环境的部位 如肾脏 肝脏 心脏 就完全不可能 通过观察这些器官 来判断人种 |
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kidneys:n.[解剖]肾脏;转炉的附着物;肾形矿脉(kidney的复数); livers:n.肝脏(liver的复数); organs:n.[生物]器官;机构;风琴(organ的复数);
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| So there's another interesting thing that comes from this realization that humans have a recent common origin in Africa, and that is that when those humans emerged around 100,000 years ago or so, they were not alone on the planet. |
由此可推断出 另外一个有趣的观点 那就是人类的共同祖先来自非洲 他们出现在 距今10年以前 但他们不是唯一的人类种群 |
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realization:n.实现;领悟; emerged:v.(从隐蔽处或暗处)出现;暴露;露出真相;显现;(emerge的过去分词和过去式)
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| There were other forms of humans around, most famously perhaps, Neanderthals -- these robust forms of humans, compared to the left here with a modern human skeleton on the right -- that existed in Western Asia and Europe since several hundreds of thousands of years. |
当时还有其他人类种群 最著名的要数尼安德特人 这些体魄强健的人类 在左边 与右边的现代人骨架相对比 他们自千百年前就一直生活在 西亚和欧洲地区 |
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famously:adv.著名地;极好地; Neanderthals:n.穴居人(Neanderthal的复数);尼安德塔人; robust:adj.强健的;健康的;粗野的;粗鲁的; compared:adj.比较的,对照的; v.相比; (compare的过去式和过去分词) skeleton:n.骨架,骨骼;纲要;骨瘦如柴的人;adj.骨骼的;骨瘦如柴的;概略的;
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| So an interesting question is, what happened when we met? |
这里有个问题很有意思 我们两种人相遇的时候 发生了什么 |
| What happened to the Neanderthals? |
尼安德特人后来怎么了 |
| And to begin to answer such questions, my research group -- since over 25 years now -- works on methods to extract DNA from remains of Neanderthals and extinct animals that are tens of thousands of years old. |
为了回答这些问题 我的研究组 从25年前 就一直在对从生活在几万年前的 穴居人以及古生物的 遗骸中提取其DNA的方法 进行研究 |
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extract:v.提取;取出;摘录;榨取;n.汁;摘录;榨出物;选粹;
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| So this involves a lot of technical issues in how you extract the DNA, how you convert it to a form you can sequence. |
提取DNA 并将它转换成可以进行排序的形式 需要用到纷繁复杂的技术 |
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involves:v.包含;需要;牵涉;牵连;影响;(使)参加,加入(involve的第三人称单数) technical:adj.工艺的,科技的;技术上的;专门的; issues:n.重要议题;争论的问题;v.宣布;公布;发出;(issue的第三人称单数和复数) convert:v.转换; n.改变宗教(或信仰、观点)的人;
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| You have to work very carefully to avoid contamination of experiments with DNA from yourself. |
工作的时候要高度谨慎 以免把你的DNA 与试验中的DNA混在一起 |
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contamination:n.污染,玷污;污染物;
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| And this then, in conjunction with these methods that allow very many DNA molecules to be sequenced very rapidly, allowed us last year to present the first version of the Neanderthal genome, so that any one of you |
通过使用这些方法 我们能够在很短的时间里将许多DNA分子排序 我们在去年 成功将首个尼安德特人基因组排序 所有人 |
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in conjunction with:连同,共同;与…协力; molecules:n.[化学]分子,微粒;[化学]摩尔(molecule的复数);
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| can now look on the Internet, on the Neanderthal genome, or at least on the 55 percent of it that we've been able to reconstruct so far. |
现在都能在网络上看到 我们到目前为止重建的 尼安德特人55%的基因组 |
| And you can begin to compare it to the genomes of people who live today. |
你可以开始把它 和现代人类的基因组作对比 |
| And one question that you may then want to ask is, what happened when we met? |
有一个问题 你可能会问到 那就是 我们碰面时 发生了什么 |
| Did we mix or not? |
我们交汇过吗 |
| And the way to ask that question is to look at the Neanderthal that comes from Southern Europe and compare it to genomes of people who live today. |
研究这个问题 就要把来自南欧的尼安德特人基因组 与现代人的基因组 相比对 |
| So we then look to do this with pairs of individuals, starting with two Africans, looking at the two African genomes, finding places where they differ from each other, and in each case ask: What is a Neanderthal like? |
接下来 我们一对对地进行比对 先比对两个非洲人 观察这两个非洲人的基因组 找出它们的差异 每次比对都要问 尼安德特人的情况呢 |
| Does it match one African or the other African? |
它是否与其中一个非洲人相匹配 |
| We would expect there to be no difference, because Neanderthals were never in Africa. |
我们认为这两个非洲人之间没有差异 因为尼安德特人从未去过非洲 |
| They should be equal, have no reason to be closer to one African than another African. |
他们应该是一样的 其中一个非洲人 不会比另一个非洲人与尼安德特人更相近 |
| And that's indeed the case. |
而事实正是如此 |
| Statistically speaking, there is no difference in how often the Neanderthal matches one African or the other. |
数据说明 尼安德特人和两个非洲人的差距是一样的 |
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Statistically:adv.统计地;统计学上;
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| But this is different if we now look at the European individual and an African. |
但是这又不同了 这次我们比对的是欧洲人和非洲人 |
| Then, significantly more often, does a Neanderthal match the European rather than the African. |
尼安德特人与欧洲人 相匹配的情况 远胜于与非洲人的匹配 |
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significantly:adv.意味深长地;值得注目地;
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| The same is true if we look at a Chinese individual versus an African, the Neanderthal will match the Chinese individual more often. |
我们在比对中国人和非洲人的时候 情况也是这样的 尼安德特人与中国人匹配的程度更高 |
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versus:prep.对;与...相对;对抗;
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| This may also be surprising because the Neanderthals were never in China. |
这也让人惊奇 因为 尼安德特人从来没有去过中国 |
| So the model we've proposed to explain this is that when modern humans came out of Africa sometime after 100,000 years ago, they met Neanderthals. |
我们提出的解释是 当现代人在10万年前 走出非洲时 他们碰上了尼安德特人 |
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proposed:adj.建议的;推荐的;v.提议;建议;计划;求婚;(propose的过去分词和过去式)
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| Presumably , they did so first in the Middle East , where there were Neanderthals living. |
他们可能首先到了中东 那里正是穴居人生活的地方 |
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Presumably:adv.大概;推测起来;可假定; Middle East:n.中东(包括亚洲西南部和非洲东北部);
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| If they then mixed with each other there, then those modern humans that became the ancestors of everyone outside Africa carried with them this Neanderthal component in their genome to the rest of the world. |
如果他们曾在那里交汇过 那么那些现代人 后来成为了非洲以外 人类的祖先 就携带了尼安德特人的基因 并把它传播到了世界各地 |
| So that today, the people living outside Africa have about two and a half percent of their DNA from Neanderthals. |
于是 今天 生活在非洲以外的人们 有2.5%的DNA 来自穴居人 |
| So having now a Neanderthal genome on hand as a reference point and having the technologies to look at ancient remains and extract the DNA, we can begin to apply them elsewhere in the world. |
我们现在有了一个穴居人基因组 作为一个参照点 又有了研究古代遗骸 并从中提取DNA的 技术 我们可以在世界其它地区采用这些技术 |
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reference point:n.参比点;参照标准; apply:v.申请;涂,敷;应用;适用;请求; elsewhere:adv.在别处;到别处;
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| And the first place we've done that is in Southern Siberia in the Altai Mountains at a place called Denisova, a cave site in this mountain here, where archeologists in 2008 found a tiny little piece of bone -- this is a copy of it -- that they realized came from the last phalanx of a little finger of a pinky of a human. |
我们首先在南西伯利亚 阿尔泰山 一个叫做德尼柔娃（Denisova）的地方 这是一个溶洞 考古学家在2008年 发现了一小片骨头 这是骨头的复制品 他们发现这是 人类小手指的趾骨 |
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Siberia:n.西伯利亚; site:n.地点;位置;场所;v.设置;为…选址; archeologists:n.考古学家(archeologist的复数形式); phalanx:n.趾骨,指骨;方阵;密集队形; little finger:n.小指; pinky:adj.带淡红色的;比较激进的;n.小指(=pinkie);
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| And it was well enough preserved so we could determine the DNA from this individual, even to a greater extent than for the Neanderthals actually, and start relating it to the Neanderthal genome and to people today. |
它的保存状态很好 让我们能够从中鉴别出这个人的DNA 其序列长度比先前 尼安德特人的DNA还要长 并将它与尼安德特人的基因组 和现代人的基因组相联系 |
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preserved:v.保护;维护;保留;保存;保养;(preserve的过去式和过去分词) extent:n.程度;范围;长度;
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| And we found that this individual shared a common origin for his DNA sequences with Neanderthals around 640,000 years ago. |
我们发现 这个人的DNA序列 源自64万年前的尼安德特人 |
| And further back, 800,000 years ago is there a common origin with present day humans. |
进一步追溯下去 到了80万年前 这个人和现代人 有共同的祖先 |
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present day:adj.现代的;当今的;现在的;现时的;
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| So this individual comes from a population that shares an origin with Neanderthals, but far back and then have a long independent history. |
这个人来自一个 与尼安德特人拥有共同祖先的种群 而在更久以前 他们有很长的独立历史 |
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independent:adj.独立的; n.无党派议员(或候选人等);
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| We call this group of humans, that we then described for the first time from this tiny, tiny little piece of bone, the Denisovans, after this place where they were first described. |
从这小小一片的骨头 通过这小小一片骨头 我们首次发现这个人种 于是我们用发现地点的名字 将他们命名为德尼柔娃人 |
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described:v.描述;形容;把…称为;做…运动;(describe的过去分词和过去式)
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| So we can then ask for Denisovans the same things as for the Neanderthals: |
对于德尼柔娃人 我们也问了同样的问题 |
| Did they mix with ancestors of present day people? |
他们与现代人的祖先何时进行交汇的？ |
| If we ask that question, and compare the Denisovan genome to people around the world, we surprisingly find no evidence of Denisovan DNA in any people living even close to Siberia today. |
如果我们问这个问题 并把德尼柔娃人的基因组 如世界各地人们的基因组相比 我们惊奇地发现 没有证据证明德尼柔娃人的DNA 与现在生活在西伯利亚的人有关系 |
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surprisingly:adv.令人惊讶地;出乎意料地 evidence:n.证据,证明;迹象;明显;v.证明;
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| But we do find it in Papua New Guinea and in other islands in Melanesia and the Pacific. |
但是 我们在巴布亚新几内亚 和一些美拉尼西亚和太平洋岛屿上找到了证据 |
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Papua:n.巴布亚岛(新几内亚岛NewGuinea的旧名); Guinea:n.几内亚;基尼(英国旧时金币名);
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| So this presumably means that these Denisovans had been more widespread in the past, since we don't think that the ancestors of Melanesians were ever in Siberia. |
由于我们认定 美拉尼西亚人的祖先从未到过西伯利亚 所以我们推测 德尼柔娃人在过去分布的地区更广 |
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widespread:adj.普遍的,广泛的;分布广的;
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| So from studying these genomes of extinct humans, we're beginning to arrive at a picture of what the world looked like when modern humans started coming out of Africa. |
通过研究 这些消亡了的人类种群的基因组 我们对现代人祖先走出非洲时的世界 有了逐步的认识 |
| In the West, there were Neanderthals; in the East, there were Denisovans -- maybe other forms of humans too that we've not yet described. |
西有尼安德特人 东有德尼柔娃人 也许还有其他 我们尚未发现的人种 |
| We don't know quite where the borders between these people were, but we know that in Southern Siberia, there were both Neanderthals and Denisovans at least at some time in the past. |
我们并不确定这些人种的分界在哪里 但我们知道尼安德特人 和德尼柔娃人都曾在南西伯利亚生活过 他们至少曾经一度共同生活在那里 |
| Then modern humans emerged somewhere in Africa, came out of Africa, presumably in the Middle East. |
现代人随后在非洲出现 走出了非洲 我们认为他们去到了中东 |
| They meet Neanderthals, mix with them, continue to spread over the world, and somewhere in Southeast Asia, they meet Denisovans and mix with them and continue on out into the Pacific. |
他们和尼安德特人交汇 接着继续分散到世界各地 到了东南亚 他们又和德尼柔娃人尼安德特人交汇 接着去到太平洋岛屿 |
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spread over:传遍,延续;遍布于…; Southeast:adj.东南的;来自东南的;n.东南;东南地区;adv.来自东南;
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| And then these earlier forms of humans disappear , but they live on a little bit today in some of us -- in that people outside of Africa have two and a half percent of their DNA from Neanderthals, and people in Melanesia |
后来 这些早期人类都消亡了 但是今天 在我们某些人 也就是那些后来走出非洲的人仍然有2.5%的DNA 来自尼安德特人 而生活在美拉尼西亚的人们 |
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disappear:v.消失;失踪;不复存在;
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| actually have an additional five percent approximately from the Denisovans. |
另有5%的DNA 来自德尼柔娃人 |
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additional:adj.附加的,额外的;
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| Does this then mean that there is after all some absolute difference between people outside Africa and inside Africa in that people outside Africa have this old component in their genome from these extinct forms of humans, whereas Africans do not? |
这是否意味着 非洲以外的人 与非洲人之间存在绝对的差异 非洲以外的人们 拥有已消亡 古人类的基因 而非洲人却没有 |
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whereas:conj.然而;鉴于;反之;
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| Well I don't think that is the case. |
我不这么认为 |
| Presumably, modern humans emerged somewhere in Africa. |
现代人被认为 最早出现在非洲 |
| They spread across Africa also, of course, and there were older, earlier forms of humans there. |
他们当然也遍布整个非洲 那里有更古老的人类种群 |
| And since we mixed elsewhere, |
既然我们曾经与其他种群杂居 |
| I'm pretty sure that one day, when we will perhaps have a genome of also these earlier forms in Africa, we will find that they have also mixed with early modern humans in Africa. |
我敢肯定 当我们找到一个 更早期人类的基因组 我们可能会发现 他们曾与早期现代人在非洲交汇 |
| So to sum up, what have we learned from studying genomes of present day humans and extinct humans? |
总结一下 从比对现今人类 与已消亡的古人类的基因组研究 我们学到了什么 |
| We learn perhaps many things, but one thing that I find sort of important to mention is that I think the lesson is that we have always mixed. |
我们也许学到了很多东西 我认为最重要的是 我们的基因交汇在了一起 |
| We mixed with these earlier forms of humans, wherever we met them, and we mixed with each other ever since. |
我们拥有这些古人类的基因 不管现代人曾在哪里与他们相遇 从那以后 我们的基因就交汇在了一起 |
| Thank you for your attention. |
非常感谢 |
| (Applause) |
（众人鼓掌） |