
Ancient humans, dubbed 'Denisovans', interbred with us - jamesbritt
http://www.bbc.co.uk/news/science-environment-12059564
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Swizec
Perhaps this is being awake for 48 hours straight talking, but this story
makes me sad.

It is plain as day that when new species emerge, old species breed with one
another. Evolution is not a discrete function. Homo Sapiens bred with Homo
Neanderthalensis and evidence to support this has existed for a while afaik.

What's truly amazing here, but sort of goes hidden in the hype around
interbreding (as seen on twitter, this article etc) is that a new species of
humans, previously unknown to science, has been discovered.

 _that_ 's the news story, not the boring interbreeding.

~~~
hugh3
Surely if they can reliably interbreed with us then they're _not_ another
species. Isn't that how "species" is defined? You'll note that the scientists
in the article aren't quoted as calling these dudes a "species", they call
them a "form".

The idea of a "species" isn't terribly well defined over time anyway. Your
mother is the same species as you, her mother is the same species as her, and
so on. But if you keep following your family tree for far enough you'll start
to find things which are clearly a different species from yourself.

~~~
scott_s
The definition I'm aware of is not actually _can_ they interbreed, but do they
do it in practice?

From
[http://www.sciencedaily.com/releases/2005/02/050211082447.ht...](http://www.sciencedaily.com/releases/2005/02/050211082447.htm):

 _Members of closely related species possess no physiological differences that
would prevent them from interbreeding.

But closely related species are distinguished by subtle differences in the
pulse rates of male crickets' simple courtship songs, a secondary sexual trait
that plays a large role in mate attraction.

Among all species of Laupala, pulse rates of male courtship songs range from
.5 to 4.2 pulses per second. Female crickets can detect these differences,
says Mendelson, and they tend to hop towards the pulse rate of their own
species and to reject songs sung at a different tempo._

Despite the fact that these crickets can interbreed (and produce fertile
offspring, unlike when, say, a female horse and a male donkey produce an
infertile mule), we consider them different species because they
systematically do not breed. I recall reading about further experiments with
similar crickets where scientists manipulated the pulse rates of one cricket
species to be the same as the other. Mating occurred.

~~~
dkarl
I think behavioral and genetic barriers are both considered factors that
affect whether crickets "can" interbreed. I'm not sure if scientists would be
consistent in applying that standard to humans, though.

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blahedo
The tone of the article was a bit strange, as was the way it kept referring to
"ancient" genes and such.

If they're genes in modern people (Melanesians), how are they any more ancient
than any other genes that exist chiefly in one population subgroup?

Isn't it becoming increasingly indefensible to talk about "our own" species
(or "us") when we know that all these species interbred and that their genetic
material lives on in modern humans, even "anatomically modern" humans?

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lucraft
Anyone else think: "Battlestar was right!" ?

^^ Also what is the correct punctuation of that sentence??

~~~
CrLf
My first thought... :)

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stcredzero
I'd like to see a more substantive caption on the diagram. I had no idea the
French were a branch of early humans. (I take it, it's actually a name for a
finding.)

~~~
shin_lao
There are very ancient traces of human groups in France and I suppose that's
where the name comes from.

Most famous example: <http://en.wikipedia.org/wiki/Lascaux>

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diego_moita
If all of this is true, then it is really astonishing.

But there's something in this article that sounds very hard to accept: DNA is
extremely fragile, it is very hard to imagine it surviving 50 000 years, even
in Siberian ice. It is even harder to imagine someone to be able to sequence
the entire genome of such species. And also: how can they affirm there's no
contamination from human DNA (e.g.: bones remaining from cannibalism)?

I'll wait to hear more confirmations of this story.

~~~
mechanical_fish
The article does not say that they sequenced the whole "ancient" genome and
indeed it is quite unlikely that they did so. They probably matched lots of
isolated segments, however.

As for contamination issues... Nothing beats the original article when working
out the odds of such a thing.

