DNA from Neandertal relative may shake up human family tree | Hacker News Reader

DNA from Neandertal relative may shake up human family tree

news.sciencemag.org

18 pointsdiodorus18 comments

So let me get this straight. The whole of Eurasia was already inhabited by human-like creatures as early as 650,000 years ago, but homo sapiens didn't leave Africa until about 100,000 years ago?

What's strange about this? Homo sapiens evolved later.

Also the dates depends on your definition of human-like. Homo erectus migrated to Euroasia 1.2 mln years ago already.

It's just weird to think that we drove them all to extinction so quickly and so effectively in a relatively short space of time. Long before we had agriculture or non stick-and-rock technology. How did we do it? A few Homo sapiens wander into Eurasia, which already has a population of millions of Homo, and all the other Homos die off?

I'm not advancing an alternative theory or saying its wrong, I'm just saying its surprising.

Survival of the fittest.

It's also possible that Neanderthals prevented modern humans from leaving Africa until their populations were already in decline for other reasons (disease? inbreeding? infighting? overhunting?). In that case we may have just sped up the inevitable.

Climat changes were very important, populations varied greatly, and many regions became uninabited and inhabited again many times over.

There are minor "ice ages" on 40 000 and 100 000 year long cycles. Every time these happen (especially when they combine) - animals and plants change, and hunter-gatherers have to migrate or starve (most starve anyway). It's almost like game reset. So neanderthals advantage wasn't that big.

Since we have ~2% Neanderthal DNA, I don't think you can say they're quite extinct.

Exactly. The current theory, I believe, is that humans didn't "exterminate" Neanderthals, we just out bred them. This might be due to differences in "character". I can't reproduce the argument here, and I don't have a link, so I'm being a bit vague but the point is, something in the Human mental make up caused us to form more successful communities than the Neanderthals. The several Hominins running around Europe in the past seem to have coexisted for some time, and interacted enough that some interbreeding took place. Over time, Neanderthal faded away, leaving only the bits of DNA we got from them.

There were never more than a few thousands Neanderthals. The rising tide from Africa just diluted them to 2%. They're not gone; they're here in you and me and Aunt Hilda.

We have 99% of chimpansee DNA and 60% of banana DNA. I don't understand how they measure the 2%, obviously it's a different metric.

EDIT: so apparently there is a way to distinguish DNA that originated in Neanderthals and we got it from them as opposed to DNA we both got froum common ancestors.

Yes. ...?

Yup. Neanderthals lived in Europe during the last ice age and followed a K-selected breeding pattern. Sapiens were in Africa and followed an R-selected breeding pattern. When the ice finally melted, Sapiens flooded into Europe and wiped the neanderthal out, apparently by eating them.

I like it when things like this happen.

When a new discovery mucks up what was assumed to be established knowledge, it causes a lot of scientists with a stake in either side to push themselves hard to do more research.

Science and society itself benefits.

I'm surprised they were allowed to publish. This has been known in some circles for at least a decade, maybe longer.

It's funny that we humans think we know things about the ancient past, everything is always a guess with data that we have no concept of how incomplete it is.

That's right; we can't know for sure and I'm sure you'll get some backlash for this comment. As with everything though, we need a balance.

If we say that we can't know for sure and give up, then no advancements would ever be made in any field. On the other hand, we should recognize that science does not claim to provide us with certainty. Many of us speaking "objectively" with scientific "facts" often become emotional and arrogant when speaking to anyone who doesn't agree with our conclusions.

I always find it really interesting how thin the evidence is, in many cases, when some of these paleontological discoveries are announced. Somebody digs up a partial skeleton, or even sometimes a single, fractured bone, and bam, it's a new, previously undiscovered species. Then we get artists renderings and theories about how this long-dead animal lived. There are some great examples from dinosaur studies - Brontosaurus vs Apatosaurus (which it seems are not the same thing anymore, haha), or the initial discoveries of the Igaunodon.

I think the DNA work is interesting and somewhat more credible than purely physiological bone work, but I'd be skeptical to read into it too much. The article says they retrieved "1 to 2 million base pairs of ancient nuclear DNA" from fragments as small as 25-40 basepairs. Wikipedia tells me that humans have over 3 billion base pairs in their genome. Assuming the Sima hominid genome is somewhere within the same order of magnitude, they found less than 1% of the total genome. I'm not a geneticist, so I have no idea how they figured out how to piece those tiny fragments of 1% of the genome together in the right order, but it seems a thin branch to go out on to draw serious conclusions.

That's true for history, as well. Archeological digs in the US have rewritten colonial history, and even Civil War history. I've often wondered how much we "know" about history is completely false.

For one small example, some years back, an office building had a natural gas leak, and at one point the roof blew off. (I was a witness.) The fire trucks came, the news choppers, and the reporters on the ground. That evening, I taped each of the local news broadcasts.

Every one of them got the fundamental facts wrong (such as calling the office building a warehouse), the timeline was wrong, etc. But those news reports are probably the only record of the event, and will go down in history as what happened.

Not that what happened there mattered, but it has made me suspicious of the veracity of news reports ever since. It doesn't even have to be malicious, the errors were just sloppy work in their desire to be done with it and move on to the next story.

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