4 ms·

What did the Neanderthals do for us?

34 points by JacobAldridge 11y ago

carsongross 11y ago
This is a very interesting topic, but the article is fluff: smoking, red hair, some diseases. I am 2.5% Neanderthal. Pffff. If you are < 3% are you even european? ;)
- puredemo 11y ago
  If she had over 3% she would have written a smarter article. ;)
lholden 11y ago
"It may seem strange that we inherited disease-causing genes at all. After all, only beneficial genes should survive, so surely over hundreds of generations we should have shaken off these unwanted contributions?" Certainly not my field, but my understanding is that unless a mutation has a direct impact on survival and fertility... then there is no evolutionary drive for it to go away. All animals have negative genes that just stick around as random "junk" which has accumulated over the years. It's not surprising that we have picked them up too.
- beloch 11y ago
  Some genes exhibit pretty complex behaviour. For example, the gene for sickle cell anemia manifests as sickle cell disease only when an individual is homozygous in that gene (i.e. They have inherited a copy of this gene from both parents). Such individuals have a host of health problems, including being more susceptible to malaria. However, individuals who are heterozygous (i.e. they inherited just one copy from one parent) for the sickle cell gene do not typically have sickle cell disease, and being heterozygous in this gene actually confers resistance to malaria. In areas where malaria is a major cause of death, the gene for sickle cell anemia is much more common than it is elsewhere.
- BurningFrog 11y ago
  > Certainly not my field, but my understanding is that unless a mutation has a direct impact on survival and fertility... then there is no evolutionary drive for it to go away. Well, genes get corrupted by random mutations, and if they have no survival value, there is no correcting force. So they drift out of the genome.
  - rtl49 11y ago
    Are you referring to genetic drift? This is a statistical phenomenon by which alleles that are near neutral for viability change in frequency until one becomes fixed. This doesn't mean that neutral mutations will invariably push the wild type out of the genome. Actually, that would be improbable in the absence of a selective pressure or an accident of history.
    - BurningFrog 11y ago
      I'm saying genes that have no survival-value will fade away due to accumulating random mutations. That's probably different from whatever you're describing.
- rtl49 11y ago
  'Junk' DNA doesn't actually contain genes. By definition, a gene encodes a functional polypeptide or RNA. This is different from alleles that are neutral for viability. An example of such an allele might be connected earlobes -- this phenotype is genetically determined, but unless there's sexual selection I'm not aware of, you are correct that we wouldn't necessarily expect the alleles involved in this phenomenon to go away. However, they might as a result of an accident of history or genetic drift.
danieltillett 11y ago
The most interesting part of this article is how much of the Neanderthal genome is still present in the non African population. I would be really interested to see the same analysis applied to the Melanesian population who are 6% or so denosovian [1]. 1. https://en.m.wikipedia.org/wiki/Denisovan https://en.m.wikipedia.org/wiki/Denisovan
Retric 11y ago
We share a lot more than 20% of our DNA with Neanderthal's ~99%. So, it's not clear exactly what they mean by this article.
- crusso 11y ago
  They factor out genes attributable to common ancestors we had with Neanderthals. They're talking about genes that were specifically modified along the Neanderthal branch of evolution and then added back to us.
  - Retric 11y ago
    Considering we are the same species and would interbreed, I don't think it's that clear which line started a given mutation. Unless they had a lot of samples to work with. IE, did a trait start with us and move to them. Or did it start with them and move to us.
    - clouddrover 11y ago
      The Tibetan adaptation to high altitudes is a good example of introgression from Denisovans: http://news.nationalgeographic.com/news/2014/07/140702-genetics-tibetan-denisovan-altitude-science/ http://news.nationalgeographic.com/news/2014/07/140702-genet...
blisterpeanuts 11y ago
What advantages did the Neanderthal genes add (or take away)? The only way to really find out is to create a modern day living Neanderthal. There's probably decades of research to do before we can pull that off, but some day it will happen. We need more than just the genome, unfortunately. We already know a surprising amount about Neanderthal humans. They were generally short, around 5'7"/170cm, but their bones and muscle attachment sites were larger, suggesting bigger and more powerful musculature. Combine hereditary strength with a vigorous lifestyle during a brutal epoch, when both predators and prey were dangerous giants, and we are looking at a truly powerful breed of humans who are thought to have been many times stronger than modern Homo Sapiens humans. It seems, though, that this great strength was not a useful enough trait to be passed on through interbreeding; the modern humans displaced H. Neanderthalensis after a few thousand years, and we definitely don't have the musculature they had, not even our Cro Magnon ancestors who were contemporary with them. Their huge braincases are another mystery. They averaged 1600 cubic cm, versus 1400 for modern humans. Were the Neanderthals smarter? Or were their brains larger, as claims one scientist, to accommodate a larger optical center for their enhanced night vision? Ah, what we would give to have a way to warp time and visit that bygone era!
- iamcurious 11y ago
  They were generally short, around 5'7"/170cm Looking at this[1] list, I would call them average. Specially when nutrition was probably less than ideal then. [1] https://en.wikipedia.org/wiki/Human_height#Average_height_around_the_world https://en.wikipedia.org/wiki/Human_height#Average_height_ar...
- zamalek 11y ago
  The other way to approach it is to create a modern human. If 3% out of 20% is Neanderthal per human it must mean that a perfect snapshot exists across multiple donors. Both are interesting but unlikely experiments.
- defen 11y ago
  > What advantages did the Neanderthal genes add (or take away)? The only way to really find out is to create a modern day living Neanderthal. There's probably decades of research to do before we can pull that off, but some day it will happen Do you want to create Khan? Because that is how you create Khan. If you're averaging a bunch of genomes to do this (e.g simple rank-based voting), and assuming most mutations are deleterious, you're probably going to end up with some sort of super-Neanderthal who is way smarter and stronger than the average human.
deleted 11y ago
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34 points by JacobAldridge 11y ago

This is a very interesting topic, but the article is fluff: smoking, red hair, some diseases. I am 2.5% Neanderthal. Pffff. If you are < 3% are you even european? ;)

puredemo 11y ago
If she had over 3% she would have written a smarter article. ;)

lholden 11y ago

"It may seem strange that we inherited disease-causing genes at all. After all, only beneficial genes should survive, so surely over hundreds of generations we should have shaken off these unwanted contributions?" Certainly not my field, but my understanding is that unless a mutation has a direct impact on survival and fertility... then there is no evolutionary drive for it to go away. All animals have negative genes that just stick around as random "junk" which has accumulated over the years. It's not surprising that we have picked them up too.

beloch 11y ago
Some genes exhibit pretty complex behaviour. For example, the gene for sickle cell anemia manifests as sickle cell disease only when an individual is homozygous in that gene (i.e. They have inherited a copy of this gene from both parents). Such individuals have a host of health problems, including being more susceptible to malaria. However, individuals who are heterozygous (i.e. they inherited just one copy from one parent) for the sickle cell gene do not typically have sickle cell disease, and being heterozygous in this gene actually confers resistance to malaria. In areas where malaria is a major cause of death, the gene for sickle cell anemia is much more common than it is elsewhere.
BurningFrog 11y ago
> Certainly not my field, but my understanding is that unless a mutation has a direct impact on survival and fertility... then there is no evolutionary drive for it to go away. Well, genes get corrupted by random mutations, and if they have no survival value, there is no correcting force. So they drift out of the genome.
- rtl49 11y ago
  Are you referring to genetic drift? This is a statistical phenomenon by which alleles that are near neutral for viability change in frequency until one becomes fixed. This doesn't mean that neutral mutations will invariably push the wild type out of the genome. Actually, that would be improbable in the absence of a selective pressure or an accident of history.
  - BurningFrog 11y ago
    I'm saying genes that have no survival-value will fade away due to accumulating random mutations. That's probably different from whatever you're describing.
rtl49 11y ago
'Junk' DNA doesn't actually contain genes. By definition, a gene encodes a functional polypeptide or RNA. This is different from alleles that are neutral for viability. An example of such an allele might be connected earlobes -- this phenotype is genetically determined, but unless there's sexual selection I'm not aware of, you are correct that we wouldn't necessarily expect the alleles involved in this phenomenon to go away. However, they might as a result of an accident of history or genetic drift.

danieltillett 11y ago

The most interesting part of this article is how much of the Neanderthal genome is still present in the non African population. I would be really interested to see the same analysis applied to the Melanesian population who are 6% or so denosovian [1]. 1. https://en.m.wikipedia.org/wiki/Denisovan https://en.m.wikipedia.org/wiki/Denisovan

Retric 11y ago

We share a lot more than 20% of our DNA with Neanderthal's ~99%. So, it's not clear exactly what they mean by this article.

crusso 11y ago
They factor out genes attributable to common ancestors we had with Neanderthals. They're talking about genes that were specifically modified along the Neanderthal branch of evolution and then added back to us.
- Retric 11y ago
  Considering we are the same species and would interbreed, I don't think it's that clear which line started a given mutation. Unless they had a lot of samples to work with. IE, did a trait start with us and move to them. Or did it start with them and move to us.
  - clouddrover 11y ago
    The Tibetan adaptation to high altitudes is a good example of introgression from Denisovans: http://news.nationalgeographic.com/news/2014/07/140702-genetics-tibetan-denisovan-altitude-science/ http://news.nationalgeographic.com/news/2014/07/140702-genet...

blisterpeanuts 11y ago

What advantages did the Neanderthal genes add (or take away)? The only way to really find out is to create a modern day living Neanderthal. There's probably decades of research to do before we can pull that off, but some day it will happen. We need more than just the genome, unfortunately. We already know a surprising amount about Neanderthal humans. They were generally short, around 5'7"/170cm, but their bones and muscle attachment sites were larger, suggesting bigger and more powerful musculature. Combine hereditary strength with a vigorous lifestyle during a brutal epoch, when both predators and prey were dangerous giants, and we are looking at a truly powerful breed of humans who are thought to have been many times stronger than modern Homo Sapiens humans. It seems, though, that this great strength was not a useful enough trait to be passed on through interbreeding; the modern humans displaced H. Neanderthalensis after a few thousand years, and we definitely don't have the musculature they had, not even our Cro Magnon ancestors who were contemporary with them. Their huge braincases are another mystery. They averaged 1600 cubic cm, versus 1400 for modern humans. Were the Neanderthals smarter? Or were their brains larger, as claims one scientist, to accommodate a larger optical center for their enhanced night vision? Ah, what we would give to have a way to warp time and visit that bygone era!

iamcurious 11y ago
They were generally short, around 5'7"/170cm Looking at this[1] list, I would call them average. Specially when nutrition was probably less than ideal then. [1] https://en.wikipedia.org/wiki/Human_height#Average_height_around_the_world https://en.wikipedia.org/wiki/Human_height#Average_height_ar...
zamalek 11y ago
The other way to approach it is to create a modern human. If 3% out of 20% is Neanderthal per human it must mean that a perfect snapshot exists across multiple donors. Both are interesting but unlikely experiments.
defen 11y ago
> What advantages did the Neanderthal genes add (or take away)? The only way to really find out is to create a modern day living Neanderthal. There's probably decades of research to do before we can pull that off, but some day it will happen Do you want to create Khan? Because that is how you create Khan. If you're averaging a bunch of genomes to do this (e.g simple rank-based voting), and assuming most mutations are deleterious, you're probably going to end up with some sort of super-Neanderthal who is way smarter and stronger than the average human.

deleted 11y ago

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