I realise this is a potentially controversial subject but I have been wondering. I have heard it mentioned in several places that modern native Europeans have 'from 2% to 4% of Neanderthal DNA" while other human populations around the world don’t.
Again I realise ‘a very small amount’ is somewhat subjective but that doesn’t seem that small to me, if you were shown a car-park full of identical expensive cars and allowed to take one of your choice but with the caveat that four of them have been randomly wired up to a bomb that will explode when you start it would that be considered a small chance?
Anyway, I was wondering if there are any known or hypothesised effects of this amount of DNA (and on a side-note, is this 4% Neanderthal DNA in addition to 100% shared DNA with other human populations?) on Europeans which aren’t present in the rest of humanity?
And on a side-note I was extremely surprised by this article I came across while searching for the maximum population of Neanderthals that ever existed, which if I’m reading it correctly never rose about 1’500 females, at least in Europe, (and I assume the same number of males)Neanderthals Were Few and Poised for Extinction | Live Science
If that was the case what is the estimated high-point of the Neanderthal population worldwide?
I once read that the last surviving population of Neanderthals are believed to have lived in a cave system on the Mediterranean coast, this lead to a very vivid and quite disturbing dream of the very last Neanderthal sitting looking out to sea as the sun set. What would it have been like, did he or she realise or suspect that they were the last of their kind? Doesn’t really bear thinking about, does it…
We don’t know all of the effects yet but research suggests that Neanderthals may have strongly influenced hair and skin color.
BTW, part of your OP isn’t quite accurate. It isn’t just whites that have significant Neanderthal gene contributions. Every group except for sub-Saharan Africans has them.
You’re right, I don’t know where I got that misconception from (I’m fairly sure it was that BBC article I mentioned, but I had a look and couldn’t locate it), still I don’t think 2% to 4% of DNA in Europeans and even higher in other human populations is a ‘very, very small amount’ as has been suggested.
Let’s leave the exact percentages in particular populations aside for a bit and concentrate on the core question of the OP.
For one, your comparison with an X number of cars of which Y are wired to a bomb is not relevant to your question. The question relates to a percentage of the DNA of every (caucasian) human, not to a chance of 3 in 100 that a random person is a Neanderthal. [insert joke about how 80% of people are likely Neanderthals here]
Next, your comparison suggests you hang on to the traditional but outdated view that Neanderthal hominids were basically half ape half humans with the mental capacities of a toddler at best. They were different from homo sapiens both fysically and mentally for sure, but not particularly dumber as far as we know. They actually had bigger brains. One thing they probably didn’t have btw was articulated speech.
Now for the effects: probably small to the point of not observable (i will check out Shagnasty’s link for sure!). Remember that each mammal species shares at least something like 98% of their genome with any other so humans share about that percentage with a bat. For more closely related extant species like a chimpansee, this percentage rises to 99.5% or so. You probably get where I’m going: the circa 3% you’re talking about in effect comes down to 3% of maybe 0.5% which is only 0.015%.
Lastly, about your vision of the last Neanderthal watching the sun set. I’m pretty sure he or she didn’t know he was the last of his species, but I bet he was feeling lonely as hell since - as member of a social species - must have been quite an ordeal to experience the death or disappearance of all his friends, family, tribe. To make it even sadder: I’m afraid there may have been dozens of lonely ‘last’ Neanderthals separated by tens of miles of wilderness, not knowing about eachother’s existence.
Another thing to remember is that Homo neanderthalensis were already very, very close to Homo sapiens, hence the ability to interbreed easily. Indeed some folks classify them as just a subspecies of H. sapiens, the dividing line is that narrow. Insomuch as ~99.5% of the genome was identical, 2-4% admixture ( or whatever ) does not make for a huge difference.
Thanks for your reply, but just one thing, I didn’t suggest or imply that Neanderthals were lesser people at all, in fact I’m fully aware that they had larger brains than us and were fully human in all respects mentally and physically, so I’m not sure where you’re getting that from.
But they weren’t Homo Sapiens Sapiens which is why I was asked my initial question, though that seems to be based on a misunderstanding/misinformation as I thought Europeans had the remnant Neanderthal DNA while other populations did not.
It’s not surprising. The idea that homo sapiens and neanderthal were completely separated for over 100,000 years never made sense to me. Whatever mixing occurred would have been in the regions where Europe bordered Asia, including the Middle East where Asians and Africans were mixing all along. Eastern Asia may seem far from Europe, but we’re talking about really long time spans for those genes to migrate. Thanks for the interesting links.
On appearance alone I suspect I have a high percentage of neanderthal genes
Some of them might have been born into mixed tribes even.
What effect do the Caucasian genes in African-American populations have? Uh… well… lesser chance of sickle cell anemia… slightly higher chance of not becoming lactose intolerant with age… certain traits in physical appearance… Subsaharian genes in the general white population will have an effect of some chance of sickle cell and on physical appearance, but you need to look at Scandinavian populations to see any type of non-Scandinavian genes add some chance of lactose intolerance, because lactose tolerance happens to be a Scandinavian trait.
To know what are the effects of Neanderthal genes we need to know either traits which are higher in Neanderthal populations (oops) or be able to identify an individual gene whose results are known as being of Neanderthal origin.
Thanks Nava, I think what I’ve taken away from this thread is that genetics etc is a subject I obviously need to do a bit more reading about.
Re mixed tribes, I did read somewhere that Neanderthal/Homo Sapiens offspring were mostly infertile, which would have contributed to the decline of the species.
Which reminds me of this, if you (general ‘you’) can get over the furry thing it actually has some interesting ideas in it, such as this sequence explaining the disapperance of one of the worlds sentient species:
btw there is quite a bit of crudity in that strip, I would have given up on it long ago if it didn’t keep occassionally surprising me with interesting concepts like that one.
Not sure where you are getting this data from. Depending on how one measures things, humans and chimps share somewhere between 95% and 98% of their DNA. I believe it is ~90% for humans and mice, and then it’s going to decline even more after that since rodents and primates are pretty closely related. When you get to the platypus, you’re not going to be anywhere near 90%. OTOH, we share something like 40% of our DNA with a carrot (again, depending on how one measures it).
As for the OP, it is thought that some of those Neanderthal genes affect our immune system. Which sorta makes sense since we invaded an area where they had lived for 200,000 years at least, and probably more like 400,000- 600,000 years (back to the time our evolutionary lines split).
This Science News article suggests that Neanderthal genes are associated with a higher risk of depression, precancerous skin lesions, and blood clots, but also with a stronger innate immune response.
Impossible for us to know that from the info we have right now, so that would have been speculation at best. Can you provide the link where you read this? (Hopefully, it wasn’t The Inheritors )
Which species? Even if it were true that the hybrids were mostly infertile, I don’t see how that would affect the population of either Neanderthals or modern humans. (And if it did, it seems like it would affect both species equally.) The fact that mules are mostly infertile isn’t threatening the survival of either horses or donkeys.
But horse and donkey breeding is done in captivity, controlled by us hoo-mans. That doesn’t tell us anything about Neanderthal/Sapiens interbreeding.
The issue might be that if mating was more likely to be F-Neanderthal to M-Sapiens, that could tie up breeding females for long periods of time in only one of the populations.