Svante Pääbo: DNA clues to our inner neanderthal

Translator: Servizo de Normalización Lingüística Reviewer: Xusto Rodriguez

Hoxe quero contarlles

que podemos aprender do estudo do xenoma

de persoas vivas

e de humanos extintos.

Pero antes diso

quero lembrarlles brevemente algo que xa saben:

What I want to talk to you about

que o noso xenoma, o noso material xenético,

is what we can learn from studying the genomes

está almacenado en case todas as nosas células, nos cromosomas,

of living people

and extinct humans.

en forma de ADN

But before doing that,

que é a famosa molécula de dobre hélice.

I just briefly want to remind you about what you already know:

A información xenética

that our genomes, our genetic material,

está contida baixo a forma dunha secuencia

are stored in almost all cells in our bodies in chromosomes

de 4 bases

abreviadas coas letras A, T, C e G.

in the form of DNA,

which is this famous double-helical molecule.

A información está dúas veces:

And the genetic information

unha en cada cadea;

algo importante

is contained in the form of a sequence

xa que cando se forman novas células estas cadeas sepáranse

of four bases

e sintetízanse novas cadeas a partir das vellas

abbreviated with the letters A, T, C and G.

And the information is there twice --

nun proceso case perfecto.

one on each strand --

Pero, claro, na Natureza

which is important,

nada é totalmente perfecto

because when new cells are formed, these strands come apart,

así que ás veces cométese un erro

new strands are synthesized with the old ones as templates

e incorpórase unha letra errónea.

in an almost perfect process.

E podemos ver o resultado

desas mutacións

But nothing, of course, in nature

ao compararmos secuencias de ADN

is totally perfect,

entre as persoas da sala, por exemplo.

so sometimes an error is made

and a wrong letter is built in.

Se comparamos o meu xenoma co seu

And we can then see the result

veremos unhas 1 200 ou 1 300 letras

of such mutations

when we compare DNA sequences

de diferenza entre nós.

among us here in the room, for example.

E estas mutacións acumúlanse

aproximadamente en función do tempo.

If we compare my genome to the genome of you,

Se incorporásemos agora un chimpancé veríamos máis diferenzas.

approximately every 1,200, 1,300 letters

Máis ou menos unha letra de cada 100

will differ between us.

vai ser diferente das do chimpancé.

And these mutations accumulate

approximately as a function of time.

E se nos interesa a historia

dun fragmento de ADN, ou do xenoma enteiro,

So if we add in a chimpanzee here, we will see more differences.

é posible reconstruír a historia do ADN

Approximately one letter in a hundred

a partir desas diferenzas que se observan.

will differ from a chimpanzee.

En xeral, representamos as nosas ideas sobre esta historia

And if you're then interested in the history

con árbores coma esta.

of a piece of DNA, or the whole genome,

Neste caso é moi simple.

you can reconstruct the history of the DNA

As dúas secuencias de ADN humano

with those differences you observe.

chegan ata un devanceiro común de hai pouco tempo.

And generally we depict our ideas about this history

Máis atrás hai un compartido cos chimpancés.

in the form of trees like this.

In this case, it's very simple.

E debido a que estas mutacións

The two human DNA sequences

ocorren máis ou menos en función do tempo

go back to a common ancestor quite recently.

un pode transformar estas diferenzas

Farther back is there one shared with chimpanzees.

para estimar o tempo

en que estes dous humanos, en xeral,

And because these mutations

compartían un devanceiro común hai medio millón de anos;

happen approximately as a function of time,

e cos chimpancés,

you can transform these differences

hai arredor dos 5 millóns de anos.

to estimates of time,

O que aconteceu nos últimos anos

where the two humans, typically,

é que apareceron tecnoloxías

will share a common ancestor about half a million years ago,

que permiten ver moitos fragmentos de ADN moi rapidamente.

and with the chimpanzees,

it will be in the order of five million years ago.

Agora podemos, en cuestión de horas,

determinar un xenoma humano completo.

So what has now happened in the last few years

Todos nós temos, claro, dous xenomas humanos:

is that there are account technologies around

that allow you to see many, many pieces of DNA very quickly.

o que vén das nosas nais e o que vén dos nosos pais.

Teñen unha lonxitude duns 3.000 millóns de letras.

So we can now, in a matter of hours,

determine a whole human genome.

E descubriremos que os meus dous xenomas,

Each of us, of course, contains two human genomes --

ou un xenoma meu que queiramos usar,

one from our mothers and one from our fathers.

terá uns tres millóns de diferenzas,

And they are around three billion such letters long.

nesa orde.

E o que se pode comezar a facer é

describir a distribución

And we will find that the two genomes in me,

destas diferenzas xenéticas no mundo.

or one genome of mine we want to use,

will have about three million differences

E ao facelo

un acha unha certa cantidade de variación xenética en África.

in the order of that.

And what you can then also begin to do

E se miramos fóra de África

is to say, "How are these genetic differences

atopamos menos variación xenética.

distributed across the world?"

And if you do that,

Isto é sorprendente, por suposto,

you find a certain amount of genetic variation in Africa.

porque hai de 6 a 8 veces menos xente

And if you look outside Africa,

vivindo dentro ca fóra de África.

Aínda así, as persoas de África

you actually find less genetic variation.

teñen máis variación xenética.

This is surprising, of course,

because in the order of six to eight times fewer people

Ademais, case todas estas variantes

live in Africa than outside Africa.

que vemos fóra de África

teñen secuencias de ADN máis estreitamente relacionadas

Yet the people inside Africa

que as de África entre si.

have more genetic variation.

Pero se vemos en África

hai unha compoñente de variación xenética

Moreover, almost all these genetic variants

we see outside Africa

que non ten parentes próximos fóra.

have closely related DNA sequences

O modelo que explica isto di

that you find inside Africa.

que unha parte da variación africana, pero non toda,

But if you look in Africa,

there is a component of the genetic variation

saíu colonizar o resto do mundo.

that has no close relatives outside.

E xunta estes métodos de datación das diferenzas xenéticas

So a model to explain this

is that a part of the African variation, but not all of it,

isto conduciu á idea

de que os humanos modernos,

[has] gone out and colonized the rest of the world.

humanos que en esencia son indistinguibles de vostedes e de min,

And together with the methods to date these genetic differences,

evolucionaron en África hai moi pouco tempo;

entre 100.000 e 200.000 anos.

this has led to the insight

that modern humans --

E despois, hai entre 100.000 e 50.000,

humans that are essentially indistinguishable from you and me --

saíron de África

evolved in Africa, quite recently,

para colonizar o resto do mundo.

between 100 and 200,000 years ago.

Por iso moitas veces gústame dicir

que, desde un punto de vista xenómico,

And later, between 100 and 50,000 years ago or so,

todos somos africanos.

Ou vivimos hoxe dentro de África

went out of Africa

ou somos exiliados moi recentes.

to colonize the rest of the world.

So what I often like to say

Outra consecuencia

desta orixe recente dos humanos modernos

is that, from a genomic perspective,

we are all Africans.

é que as variantes xenéticas

We either live inside Africa today,

están en xeral amplamente distribuídas polo mundo,

or in quite recent exile.

en moitos lugares,

Another consequence

e tenden a variar como gradientes

of this recent origin of modern humans

polo menos miradas a vista de paxaro.

is that genetic variants

E dado que hai moitas variantes xenéticas

are generally distributed widely in the world,

in many places,

e teñen diferentes gradientes,

and they tend to vary as gradients,

se determinamos unha secuencia de ADN,

from a bird's-eye perspective at least.

un xenoma dun individuo,

podemos estimar con bastante precisión

And since there are many genetic variants,

and they have different such gradients,

de onde vén esa persoa

sempre que seus pais ou seus avós

this means that if we determine a DNA sequence --

non se moveran demasiado.

a genome from one individual --

Pero, significa isto,

como moita xente adoita pensar,

we can quite accurately estimate

que hai grandes diferenzas xenéticas entre grupos de persoas

where that person comes from,

provided that its parents or grandparents

nos distintos continentes, por exemplo?

haven't moved around too much.

Ben, podemos empezar a facer estas preguntas.

But does this then mean,

Por exemplo, hai en marcha un proxecto

as many people tend to think,

para secuenciar o xenoma dun milleiro de individuos

that there are huge genetic differences between groups of people --

de diferentes partes do mundo.

on different continents, for example?

Well we can begin to ask those questions also.

Secuenciáronse 185 africanos

de dúas poboacións en África.

There is, for example, a project that's underway

Secuenciáronse outros tantos máis ou menos

to sequence a thousand individuals --

their genomes -- from different parts of the world.

en Europa e na China.

They've sequenced 185 Africans

E podemos empezar a contar cantas variacións atopamos,

from two populations in Africa.

cantas letras varían,

[They've] sequenced approximately equally [as] many people

polo menos nunha destas secuencias individuais.

in Europe and in China.

E son unha chea: 38 millóns de posicións variables.

And we can begin to say how much variance do we find,

Pero podemos preguntarnos: hai diferenzas absolutas

how many letters that vary

entre africanos e non africanos?

in at least one of those individual sequences.

Se cadra a maioría de nós

pensamos que hai unha gran diferenza.

And it's a lot: 38 million variable positions.

E con diferenza absoluta

quero dicir unha diferenza

But we can then ask: Are there any absolute differences

en que a xente de África teña unha posición

between Africans and non-Africans?

todos os individuos, o 100%, teñan unha letra

Perhaps the biggest difference

most of us would imagine existed.

e todos fóra de África teñan outra diferente.

And with absolute difference --

and I mean a difference

E a resposta a esa pregunta, entre eses millóns de diferenzas,

where people inside Africa at a certain position,

é que non nin unha posición en que iso ocorra.

where all individuals -- 100 percent -- have one letter,

and everybody outside Africa has another letter.

Isto pode ser sorprendente.

Se cadra, un individuo está mal clasificado.

And the answer to that, among those millions of differences,

Por iso podemos relaxar algo o criterio

is that there is not a single such position.

e dicir: cantas posicións atopamos

en que o 95% da xente de África teña

This may be surprising.

unha variante

e o 95% fóra de África teña outra,

Maybe a single individual is misclassified or so.

e o total son 12.

So we can relax the criterion a bit

Isto é moi sorprendente.

and say: How many positions do we find

Iso significa que ao observarmos persoas

where 95 percent of people in Africa have

e ver unha de África

one variant,

95 percent another variant,

e unha de Europa ou Asia

and the number of that is 12.

non hai ningunha posición no xenoma para a que poidamos predicir ao 100 %,

So this is very surprising.

It means that when we look at people

a súa carga xenética.

and see a person from Africa

E só para 12 posicións

podemos esperar estar seguros ao 95 %.

and a person from Europe or Asia,

we cannot, for a single position in the genome with 100 percent accuracy,

Isto pode sorprender

porque, obviamente, podemos mirar para eles

predict what the person would carry.

e dicir facilmente de onde veñen eles ou os seus devanceiros.

And only for 12 positions

can we hope to be 95 percent right.

Xa que logo, isto significa

que eses trazos que ao mirarmos

This may be surprising,

vemos tan facilmente...

because we can, of course, look at these people

trazos faciais, cor da pel, estrutura do cabelo...

and quite easily say where they or their ancestors came from.

non están determinados por xenes únicos con grande influencia,

So what this means now

is that those traits we then look at

senón por moitas variantes xenéticas diferentes

and so readily see --

que se presentan con frecuencias diversas

facial features, skin color, hair structure --

en diferentes partes do mundo.

are not determined by single genes with big effects,

Hai outra cousa en relación con estes trazos

que observamos con facilidade nos outros

but are determined by many different genetic variants

que me parece digno de mención:

that seem to vary in frequency

nun sentido moi literal,

between different parts of the world.

There is another thing with those traits

están realmente na nosa superficie corporal.

that we so easily observe in each other

Son, como acabamos de dicir,

trazos faciais, estrutura do cabelo, cor de pel.

that I think is worthwhile to consider,

Hai tamén unha serie de características

and that is that, in a very literal sense,

que varían entre continentes, coma as anteriores,

they're really on the surface of our bodies.

que teñen que ver con como metabolizamos os alimentos que inxerimos

They are what we just said --

facial features, hair structure, skin color.

ou coa forma

en que o noso sistema inmune enfronta os microbios

There are also a number of features

que tratan de invadir os nosos corpos.

that vary between continents like that

that have to do with how we metabolize food that we ingest,

Pero todas esas son partes do corpo

coas que interactuamos directamente co medio,

or that have to do

en confrontación directa, se se quere.

with how our immune systems deal with microbes

that try to invade our bodies.

É fácil imaxinar

como esas partes do corpo

But so those are all parts of our bodies

se viron rapidamente influídas pola selección do medio ambiente,

where we very directly interact with our environment,

in a direct confrontation, if you like.

o que alterou as frecuencias de xenes

involucradas nelas.

It's easy to imagine

Pero se observamos outras partes do corpo

how particularly those parts of our bodies

coas que non interactuamos directamente co medio

were quickly influenced by selection from the environment

-riles, fígados, corazóns-

and shifted frequencies of genes

non hai xeito de dicir

that are involved in them.

só mirando eses órganos

But if we look on other parts of our bodies

de que parte do mundo veñen.

where we don't directly interact with the environment --

Hai outra cousa interesante

our kidneys, our livers, our hearts --

que deriva desta constatación

there is no way to say,

de que os seres humanos teñen unha orixe común recente en África:

by just looking at these organs,

where in the world they would come from.

cando eses seres humanos apareceron

So there's another interesting thing

hai uns 100.000 anos

that comes from this realization

non estaban sós no planeta.

that humans have a recent common origin in Africa,

Andaban arredor outras formas de humanos,

os máis famosos, se cadra, os neanderthais,

and that is that when those humans emerged

--esas variedades robustas de humanos

around 100,000 years ago or so,

da esquerda comparadas

they were not alone on the planet.

cos esqueletos modernos da dereita--

There were other forms of humans around,

que existiron no oeste de Asia e en Europa

most famously perhaps, Neanderthals --

desde hai centos de miles de anos.

these robust forms of humans,

compared to the left here

Así que unha pregunta interesante é:

with a modern human skeleton on the right --

que pasou cando nos atopamos?

Que lles sucedeu aos neanderthais?

E para empezar a responder estas preguntas

that existed in Western Asia and Europe

o meu grupo de investigación traballa --desde hai máis de 25 anos--

since several hundreds of thousands of years.

So an interesting question is,

en métodos para extraer ADN

what happened when we met?

en restos de neanderthais

What happened to the Neanderthals?

e animais extintos

And to begin to answer such questions,

que teñen decenas de miles de anos.

my research group -- since over 25 years now --

Isto implica unha chea de cuestións técnicas

works on methods to extract DNA

sobre a forma de extraer o ADN,

from remains of Neanderthals

sobre como convertelo en algo que poida secuenciarse.

and extinct animals

that are tens of thousands of years old.

Hai que traballar con moito coidado

para evitar a contaminación dos experimentos

So this involves a lot of technical issues

co ADN propio.

in how you extract the DNA,

E así, xunto con eses métodos

how you convert it to a form you can sequence.

que permiten secuenciar moi rapidamente moitas moléculas de ADN,

You have to work very carefully

to avoid contamination of experiments

permitiunos presentar o ano pasado

with DNA from yourself.

a primeira versión do xenoma neanderthal

And this then, in conjunction with these methods

de xeito que calquera de vostedes

pode agora velo en Internet,

that allow very many DNA molecules to be sequenced very rapidly,

ou polo menos o 55% do total

allowed us last year

que fomos quen de reconstruír ata agora.

to present the first version of the Neanderthal genome,

E pódese empezar a comparalo cos xenomas

so that any one of you

da xente que vive na actualidade.

can now look on the Internet, on the Neanderthal genome,

or at least on the 55 percent of it

E unha pregunta

que poden querer formular

that we've been able to reconstruct so far.

é... que ocorreu cando nos coñecemos?

Mesturámonos ou non?

And you can begin to compare it to the genomes

E a maneira de responder esa pregunta

of people who live today.

é observar os neanderthais procedentes do sur de Europa

And one question

e comparar os seus xenomas

that you may then want to ask

cos da poboación actual.

is, what happened when we met?

Así, buscamos

Did we mix or not?

facer isto con pares de individuos

And the way to ask that question

empezando con dous africanos,

is to look at the Neanderthal that comes from Southern Europe

observando dous xenomas africanos,

and compare it to genomes

atopando lugares onde difiren un do outro,

of people who live today.

e en cada caso preguntámonos: a quen se parece o neanderthal?

So we then look

to do this with pairs of individuals,

Con cal dos africanos coincide?

starting with two Africans,

looking at the two African genomes,

O esperable sería non achar diferenzas

finding places where they differ from each other,

porque os neanderthais nunca estiveron en África.

and in each case ask: What is a Neanderthal like?

Deberían ser iguais, non hai razón para que estean máis cerca

Does it match one African or the other African?

dun africano ca do outro.

E así é na realidade.

We would expect there to be no difference,

Estatisticamente falando, non hai diferenzas

because Neanderthals were never in Africa.

na frecuencia en que os neanderthais coinciden cun africano ou con outro.

They should be equal, have no reason to be closer

to one African than another African.

Pero as cousas cambian

se comparamos un individuo europeo e un africano.

And that's indeed the case.

Statistically speaking, there is no difference

Entón, con moita máis frecuencia

in how often the Neanderthal matches one African or the other.

o neanderthal coincide co europeo

antes ca co africano.

But this is different

E o mesmo pasa se comparamos un individuo chinés

if we now look at the European individual and an African.

cun africano:

Then, significantly more often,

o neanderthal coincidirá máis a miúdo co individuo chinés.

does a Neanderthal match the European

Isto tamén pode sorprender

rather than the African.

porque os neanderthais nunca estiveron en China.

The same is true if we look at a Chinese individual

Así que o modelo que propuxemos para explicar isto

versus an African,

the Neanderthal will match the Chinese individual more often.

é que cando os humanos modernos saíron de África

hai uns 100.000 anos

This may also be surprising

atoparon aos neanderthais.

because the Neanderthals were never in China.

So the model we've proposed to explain this

Supoñemos que ocorreu por primeira vez en Oriente Medio

onde vivían neanderthais.

is that when modern humans came out of Africa

Se alí se mesturaron uns con outros

sometime after 100,000 years ago,

entón eses humanos modernos

que acabaron sendo devanceiros

they met Neanderthals.

de todos nós fóra de África

Presumably, they did so first in the Middle East,

levaron consigo no seu xenoma o compoñente neanderthal

where there were Neanderthals living.

If they then mixed with each other there,

ao resto do mundo.

then those modern humans

Así que hoxe, a xente que vive fóra de África

that became the ancestors

ten preto do 2,5% do seu ADN

of everyone outside Africa

carried with them this Neanderthal component in their genome

de orixe neanderthal.

Ao termos hoxe un xenoma neanderthal

to the rest of the world.

dispoñible como punto de referencia

So that today, the people living outside Africa

e ao termos as tecnoloxías

have about two and a half percent of their DNA

para observar restos antigos

from Neanderthals.

e extraer deles o ADN,

So having now a Neanderthal genome

podemos empezar a aplicalas en calquera lugar do mundo.

on hand as a reference point

E o primeiro lugar onde o fixemos foi no sur de Siberia,

and having the technologies

to look at ancient remains

nas montañas Altai,

and extract the DNA,

nun lugar que se chama Denisova,

nunha cova desa montaña

we can begin to apply them elsewhere in the world.

na que en 2008 os arqueólogos

And the first place we've done that is in Southern Siberia

acharon un anaquiño de óso

in the Altai Mountains

--velaquí unha copia--

at a place called Denisova,

e decatáronse de que proviña da última falanxe

a cave site in this mountain here,

dun maimiño humano.

where archeologists in 2008

found a tiny little piece of bone --

E estaba tan ben conservado

this is a copy of it --

que foi posible determinar o ADN deste individuo

that they realized came from the last phalanx

incluso nunha extensión maior

que para os neanderthais,

of a little finger of a pinky of a human.

e comezouse a relacionalo co xenoma neanderthal

And it was well enough preserved

e co de persoas de hoxe.

so we could determine the DNA from this individual,

E descubrimos que este individuo

even to a greater extent

compartía unha orixe común para as súas secuencias de ADN

than for the Neanderthals actually,

cos neandertais de hai preto de 640.000 anos.

and start relating it to the Neanderthal genome

and to people today.

E máis atrás, hai 800.000 anos

And we found that this individual

hai unha orixe común

shared a common origin for his DNA sequences

cos humanos actuais.

with Neanderthals around 640,000 years ago.

Este individuo provén dunha poboación

que comparte unha orixe cos neanderthais

And further back, 800,000 years ago

pero indo cara a atrás, ten unha longa historia independente.

is there a common origin

Chamámoslles a este grupo de humanos,

with present day humans.

que describimos por vez primeira

So this individual comes from a population

a partir deste diminuto anaco de óso,

that shares an origin with Neanderthals,

denisovanos,

polo lugar onde se descubriron por primeira vez.

but far back and then have a long independent history.

We call this group of humans,

Podemos preguntarnos sobre os denisovanos

that we then described for the first time

o mesmo que fixemos sobre os neanderthais:

from this tiny, tiny little piece of bone,

mesturáronse con devanceiros dos humanos actuais?

the Denisovans,

after this place where they were first described.

Si nos facemos esa pregunta

e comparamos o xenoma denisovano

So we can then ask for Denisovans

co dos humanos de todo o mundo

the same things as for the Neanderthals:

atopamos con sorpresa

Did they mix with ancestors of present day people?

que non hai evidencia de ADN denisovano

nin sequera entre as persoas que hoxe viven preto de Siberia.

If we ask that question,

and compare the Denisovan genome

Pero atopámolo en Papúa Nova Guinea

to people around the world,

we surprisingly find

e noutras illas de Melanesia e o Pacífico.

no evidence of Denisovan DNA

in any people living even close to Siberia today.

Isto significa, probablemente,

que estes denisovanos estiveron máis dispersos no pasado

But we do find it in Papua New Guinea

porque non cremos que os devanceiros dos melanesios

and in other islands in Melanesia and the Pacific.

estiveran en Siberia.

Así, a partir do estudo

So this presumably means

destes xenomas de humanos extintos

that these Denisovans had been more widespread in the past,

estamos a empezar a ter unha imaxe de como era o mundo

since we don't think that the ancestors of Melanesians

cando os humanos modernos saíron de África.

were ever in Siberia.

So from studying

En Occidente había neanderthais;

these genomes of extinct humans,

en Oriente había denisovanos...

e se cadra tamén outras variedades de humanos

we're beginning to arrive at a picture of what the world looked like

que aínda non describimos.

when modern humans started coming out of Africa.

Non coñecemos ben as fronteiras entre estas xentes

In the West, there were Neanderthals;

pero sabemos que no sur de Siberia

in the East, there were Denisovans --

había tanto neanderthais como denisovanos,

maybe other forms of humans too

polo menos nalgún momento do pasado.

that we've not yet described.

Os humanos modernos xurdiron nalgún lugar de África;

We don't know quite where the borders between these people were,

saíron de África, probablemente cara ao Oriente Medio.

but we know that in Southern Siberia,

there were both Neanderthals and Denisovans

Atoparon os neanderthais, mesturáronse con eles,

at least at some time in the past.

continuaron estendéndose polo mundo

Then modern humans emerged somewhere in Africa,

e nalgún lugar no sueste de Asia

came out of Africa, presumably in the Middle East.

atoparon os denisovanos e mesturáronse con eles

e continuaron cara ao Pacífico.

They meet Neanderthals, mix with them,

continue to spread over the world,

Despois estas formas temperás de humanos desapareceron

and somewhere in Southeast Asia,

pero hoxe viven un pouco

they meet Denisovans and mix with them

nalgúns de nós

nesas persoas de fóra de África que teñen o 2,5% do seu ADN

and continue on out into the Pacific.

And then these earlier forms of humans disappear,

de orixe neanderthal

e nas persoas de Melanesia

but they live on a little bit today

que teñen máis ou menos un 5% adicional

in some of us --

de orixe denisovana.

in that people outside of Africa have two and a half percent of their DNA

Significa isto que existe a pesar de todo

from Neanderthals,

algunha diferenza absoluta

and people in Melanesia

entre as persoas de fóra de África e as de dentro

actually have an additional five percent approximately

no feito de que as persoas de fóra de África

from the Denisovans.

teñan este compoñente ancestral no seu xenoma

Does this then mean that there is after all

con orixe nestas formas humanas extintas

some absolute difference

mentres que os africanos non?

between people outside Africa and inside Africa

Ben, non creo que sexa así.

in that people outside Africa

Probablemente, os humanos modernos

xurdiron nalgún lugar de África.

have this old component in their genome

Espalláronse por África, claro,

from these extinct forms of humans,

whereas Africans do not?

e había alí formas humanas máis vellas, máis temperás.

Well I don't think that is the case.

E como nos mesturamos nalgún lado

Presumably, modern humans

estou bastante seguro que un día

emerged somewhere in Africa.

cando quizá teñamos un xenoma

They spread across Africa also, of course,

destas formas temperás de África

and there were older, earlier forms of humans there.

imos atopar que tamén se mesturaron

con humanos modernos temperáns en África.

And since we mixed elsewhere,

I'm pretty sure that one day,

Para resumir:

when we will perhaps have a genome

que aprendemos ao estudar xenomas

of also these earlier forms in Africa,

de humanos actuais

we will find that they have also mixed

e humanos extintos?

with early modern humans in Africa.

Se cadra, aprendemos moitas cousas,

pero unha que me parece importante mencionar

So to sum up,

what have we learned from studying genomes

é que creo que a lección é que sempre nos mesturamos.

of present day humans

and extinct humans?

Mesturámonos con estas formas temperás de humanos

We learn perhaps many things,

onde for que nos atopamos

but one thing that I find sort of important to mention

e mesturámonos uns con outros desde aquela.

is that I think the lesson is that we have always mixed.

Grazas pola súa atención.

(Aplausos)

We mixed with these earlier forms of humans,

wherever we met them,

and we mixed with each other ever since.

Thank you for your attention.

(Applause)