Because skin tone is an environmental response which would be rapidly selected for. Now it seems some of the Neanderthal DNA would be selected against in this environment, seeing as it’s seemingly tied to things like skin and hair colour. But why would the e.g. superior lipid digestion Neanderthal codings be removed? Those would be more likely to be preserved over less-beneficial sapiens equivalents, no?
Good point. One of the interesting things you find genetically is Y-chromosome haplogroup R1b, which is primarily associated with Romance and Celtic language speakers in Europe (e.g. Irish, Scots Highlanders, Spaniards, French) but is also common in Cameroon.
I am not aware of a single population geneticist who thinks the occasional example of backflow of any genes from post-Levant populations is so penetrated into sub-saharan africa that we’ve become essentially similar genetic pools. There are well documented examples of backflow into east african populations and some groups in the Saheel. There are interesting isolated examples of particular genes found in odd places. But the Khoisan, for example, are something like 75% L0; you would not find anything close to that frequency for L0 haplogroups in, say, a Japanese population.
WRT Neanderthal genes in particular, I am not aware of any population geneticist who thinks the reason we haven’t found the same penetration in sub-saharan populations is because we have not looked. While sub-saharan groups are not as well studied, it’s pretty broadly accepted dogma that sub-saharans are considerably isolated historically from eurasian populations, for the migration reasons I mention above. 40kya there are not a lot of Levantine genes flowing back into sub-saharan africa, within any haplogroup.
I am afraid I can’t help you understand this. mtDNA and Y haplogroups are used as markers to track ancestral groups, migration patterns and distance from confluent ancestral groups. It’s not a question of how much mtDNA or Y haplogroups DNA represent as part of the total genome.
Some additional reading on how the world was peopled might help. That picture represents a combination of physical (archaeology, e.g.) evidence and mtDNA/Y haplogroup markers.
Look to the OP for the answer to your question. We’ve addressed it in posts you may have missed.
We self-identify into “black, white, asian” (and a few others, but these are the biggies.
We have a deep interest in making sure the fruits of society are available to all. In the US, we effect that goal with race-based affirmative action. We have historically justified this on the basis of nurturing disadvantage toward those who self-identify as black.
We now have large enough pools of wealthy and educated black families. When we factor out poverty, we are still left with a substantial performance gap. No one has been able to find any correctable nurturing influences to eliminate that gap, and it is quite profound. To give you one statistic, on the SAT, black children from families with incomes of $80-100K scored barely on par with whites from families with incomes at about $10K.
Race-based AA is under attack. Since the core belief is that we are all more or less equivalently abled genetically, the argument is that only lack of opportunity should create preferences, without self-identification of race being considered. When that approach is taken, the best black candidates get eliminated from consideration for the best schools and the best jobs. This is because the best black candidates come from the wealthiest tiers and the highest parental educational backgrounds. Those best black candidates, though, are competing against much higher scores from their socioeconomic peers, and this disparity is present at every SES tier.
The result of this is that, without a race-alone boost up, blacks would suffer a significant setback in participation across many middle class and higher jobs. Whether you are talking about a fireman’s advancement test, or a physician, the qualifying exams always have the same general rank order, with blacks performing at the bottom regardless of opportunity (socioeconomic; parental education) background.
If we decide that all average self-identified pools have about equal potential, then a mindset sets in that a high-opportunity, underperforming black candidate is just not trying, or has some other unacceptable excuse for underperforming. After all, his opportunity was the same or better.
For one individual; no big deal. At a group average, a very big problem.
A broad acceptance of genetic egalitarianism will kill race-based AA. And that will be a very sad day for the US. It is happening already.
We can, instead, simply accept that not all groups have the same average gene pool. We don’t think women have the same genes as men, and we find ways to accommodate that, not obsess about it, and move on. We can do the same for self-identified race, and our society will be better for it.
If neighboring groups have different patterns of mtDNA, this only tells us about how the mother’s mother’s mother’s lines look, genetically, not how the entire group’s genome looks. The neighboring groups might well be closely related, despite the different mtDNA – due to some accident (or something on purpose due to a quirk of culture and history) they just had different maternal lines.
You’re just saying “that’s how it is”. That’s not enough. At the very least, show me two neighboring groups – any two in or around NE Africa or SW Asia – that have been neighbors for a long, long time, but share no recent ancestry.
If you don’t want to, we can move on to the lack of information about the genes for intelligence, much less its prevalence in different groups; the experimental evidence that refutes the genetic explanation and your side’s cowardly dismissal of a good scientific attitude that would seek to recreate what would be a relatively easy experiment; and your absurd assertion that, contrary to pretty much all of human history and especially American history of the last few hundred years, widespread acceptance of the genetic intellectual inferiority of black people would actually help black people.
Not sure that there has been any experimental evidence since James Lee’s 2009 review of Richard Nisbett’s book to further the case. At that point Lee found that the evidence didn’t refute the genetic or partial genetic explanation.
Lee also proposed a means of comparing allele frequencies which as far as I’m aware Nisbett and others haven’t pursued?
So far the only tentative evidence regarding actual genes has been outlined by Piffer (see my post above).
Certainly if there was experimental evidence refuting one side of the argument you wouldn’t get the kind of survey results that were reported in the 1980’s and again a year or so ago. Most researchers surveyed don’t really know. Of those that do hold a view far more consider it a combination of genetic and environmental variation than a sole genetic or environmental cause.
Unfortunately, this kind of information simply reinforces the following:
Average gene pools for sub-saharan and non-african genetic variants is quite different. Reich and everyone else studying population genetics do not think these are the same pools. Instead, they accept that these are quite different pools. If, 2,000 years ago some eurasian gene variants made it back to africa, and if some of those variants made it to some of the Khoisan, we’d see exactly what this kind of research reveals: A very small fraction of the overall sub-saharan population in southern africa has a little bit of the “eurasian” gene pool.
You can spin this to leave an inference that everbody has everybody else’s gene pools, but it is saying exactly the opposite. There is a eurasian gene pool. There is a sub-saharan gene pool. They have been largely separated by tens of thousands of years. Where there has been mixing in recent times, it has been on a small scale, helping us understand some interesting migration patterns.
What has not happened is that these genetic pools have become homogenized. The headline can read “Hey; africans haved neanderthal genes too!” But the content is going to say “A few african populations, a small percentage of the eurasian gene pool, and therefore a much much much smaller overall percentage of neanderthal genes in the total subsaharan pool.”
I am curious if you accept or reject the fundamental pattern of human migration, and the out of africa single-point exit that is outlined in the various cites I’ve given you, above?
And I’m curious if you feel like the population ancestries worked out using mtDNA and Y haplogroups is correct for its approximate coalescence points with common ancestors?
I have not found much support for an alternative paradigm. Have you, and can you cite some sources?
And that’s a difference of precisely 1 SNP (so <0.1% genetic difference) so … ? It doesn’t make the Japanese vastly different genetically from the Khoi-San. In fact, the fact that such tiny variations have to be used to distinguish human populations points to the truth: that there’s no large-scale differentiation, races don’t exist.
If you’re splitter enough to want to distinguish people on a < 0.1% difference, that’s great for you. Don’t expect science to follow suit. Scientists as a whole, as organizations and individuals, have already decided that’s not enough to matter.
And amongst archaeologist 50 years ago, you’d not have found many who would have said African independently developed iron and steel production and agriculture. Then they actually started looking.
Africa is the second-largest continent with the second-largest population and the longest human history. It’s also, for various reasons, the least-studied continent in most every scientific endeavour. I wouldn’t be so certain about what would and wouldn’t be found in Africa - who was expecting a frigging Lost Tribe of Israel to be in South Africa? Or Southern European affiliations in the Bushmen? So no, I’m not going to rely on accepted wisdom about human migration. Especially when the most recent work is saying that the one-way pump model is not accurate.
This says all I need to know about your approach to Science.
Lee performed no experiments. There is specific experimental data (the Scarr study that I’ve linked to numerous times) that refutes the genetic explanation – it shows that greater levels of African ancestry (measured by “blood group loci” – an older DNA marker/method) among self-identified African Americans does not correlate with lower IQ scores.
If you, or Lee, or CP, or anyone else doesn’t like the results from the Scarr study, feel free to actually do some science and use modern methods to recreate the study. It wouldn’t be that hard, and it wouldn’t be that expensive.
Bullshit. You’re just ignoring any data that you don’t like.
The fact that researchers are mostly unsure does not convince me that black people are inherently intellectually inferior on average due to genetics.
I accept it. It doesn’t refute any of my claims.
For rough approximations, sure. But mt and Y DNA can’t account for ancestry across the entire genome between groups (in fact, by your own cites, they often don’t even agree on which groups are closely related or not!). There are many scenarios in which two groups can be closely related but they have significantly different patterns of mt or Y DNA.
Your own cites support an “alternative paradigm”, if your paradigm is that mt and Y DNA can track with close to 100% accuracy whether populations are related. If this were true, then they wouldn’t disagree so often.
Since you have presented no data on relationships across the entire genome, here are some scenarios that should be intuitively easy to understand – say there are two neighboring populations, A and B, living on opposite sides of a river. Occasionally they intermingle. At some point, population B is short on resources and goes on a raid down the river, attacking population C. B is victorious – they lose a big chunk of their male population, but return with several women and children from population C. At the same time, starving stragglers from population D up the river, recently raided themselves, come down and merge with population A.
A and B continue to have occasional interchanges, but in a few generations their mt and Y DNA could be wildly divergent, despite a somewhat close genetic relationship based on mostly shared ancestry.
I am afraid you’ve confused markers (probably 23andMe, in this case)with total variation. The L0 Khoisan lineages have been separated from the M-N descendant lineages we see in east asia for over 100,000 years, and the amount of variance in SNPs is robust. Just for Neanderthal genetic material alone, we would see an average difference of 1-4% for whole gene variants versus some very tiny fraction in the overall predominately L0 groups.
Any number of people were not that surprised to find the “Lost Tribe of Israel” in africa, and found it a more reasonable explanation of how Great Zimbabwe came to be. 
To date, the DNA story unfolding in africa is not going in a direction that vitiates general scientific consensus about how mankind arose and how the world was peopled. Backflow gene stories are interesting and colorful precisely because they are an exception to the general rule of separated source populations; not because they are creating a picture of a homogenized gene pool for all.
Great job sneaking in a “black people are too dumb to build a great civilization” dig, complete with winky face.
The coalescence point for a typical modern predominately L0 sub saharan group and a predominately D4a group in east asia is more than a hundred thousand years.
You are living in a fantasy world of wordsmithing and exceptions if you think these two ends of the spectrum have been living on the opposite sides of a river for lo these thousand centuries. Even in the Holocene there has barely been any transmission of gene variants from one side to the other, and then only enough to make some interesting sidebars. Interesting because they represent such an exception to these widely separated gene pools.
It is for this reason that population geneticists talk about “sub-saharan” and “non-african” groups.
Average. Separation. Tens of thousands of years. Because of the out of africa migration event 70kya.
It wasn’t a river that separated these two groups. See the illustration I gave you in the Tishkoff cite if you want to see the separation graphically.
Here, for example, for a typical use of language around these two pools:
mtDNA Variation in the South African Kung and Khwe—and Their Genetic Relationships to Other African Populations
" …This marker was subsequently found at very high frequencies in mtDNAs of other sub-Saharan African populations but was not observed in populations of non-African origin, with a few exceptions…"
Nothing in my assertions conflicts with the idea that east Asians and sub-Saharan Africans are not closely related at all. I’m talking about clines, and neighboring groups along the way from Africa to Japan (and elsewhere). Each group is pretty closely related to neighboring groups, including in North Africa and the Middle East, for the most part. If you deny this, then show me the neighboring groups that are not closely related – and show me the data across the entire genome (not just mt or Y DNA) that demonstrates this.
Maybe it’s along the Nile River in southern Egypt. Or northern Sudan. Or Somalia. Or Yemen. Or Sinai. If what you’re saying is true, then because humans live pretty much continuously in varying concentrations along the “road” from sub-Saharan Africa to East Asia and Europe and elsewhere, then there must necessarily be a “break” between sub-Saharan African and Eurasian DNA. Where is this break?
I don’t believe you’ll find such a break.
No. I’m pointing out that you pointing out a single point of variance does little to counter the fact that there is minimal variation.
Yes, “many people” are, in fact, racists. This should be a surprise to me because ?
It’s not a “general rule”, it’s the status quo primarily because the work hasn’t been done. Now the work is being done, and we find all these “exceptions” - Bushmen, Lemba, Yoruba…my, how exceptional they all are…:dubious:
Kind of like how your idol Lynn didn’t actually do any IQ testing in Africa, he just relied on received wisdom. And we all know how fucked-up and unscientific his actual dataset was because of it, and what a pathetic excuse for science it makes of his work. Kind of like that, drawing conclusions about African genetics without actually studying African genetics.
“exceptions” again… what a surprise.
Go easy on them, Dibs… studying African genetics would mean that they’d actually have to interact with African people.