Deep ancestry thread - where did different ethnicities originate genetically?

[Professor Emeritus]

I've been fascinated by this stuff for a long time. For reference, the main resource I'm going to use in this thread is this study, published in Nature in 2017. This study isn't definitive and I'm sure more and more accurate work will appear over time, but I like it because it's one of the most comprehensive to date and appears to agree with the results of most of the other recent large-scale studies. Feel free to add other studies and information, as I will add to some parts as I post.

Human ancestry correlates with language and reveals that race is not an objective genomic classifier​

main article: Human ancestry correlates with language and reveals that race is not an objective genomic classifier

supplemental data (pdf download): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5431528/bin/41598_2017_1837_MOESM1_ESM.pdf

Genetic and archaeological studies have established a sub-Saharan African origin for anatomically modern humans with subsequent migrations out of Africa. Using the largest multi-locus data set known to date, we investigated genetic differentiation of early modern humans, human admixture and migration events, and relationships among ancestries and language groups. We compiled publicly available genome-wide genotype data on 5,966 individuals from 282 global samples, representing 30 primary language families. The best evidence supports 21 ancestries that delineate genetic structure of present-day human populations. Independent of self-identified ethno-linguistic labels, the vast majority (97.3%) of individuals have mixed ancestry, with evidence of multiple ancestries in 96.8% of samples and on all continents. The data indicate that continents, ethno-linguistic groups, races, ethnicities, and individuals all show substantial ancestral heterogeneity. We estimated correlation coefficients ranging from 0.522 to 0.962 between ancestries and language families or branches.

Basically, they're saying that mathematically it makes more sense to split mankind into 21 different ancestral groups than to split them into 4 races. And in reality, the divisions between groups are so vague that they could have split humanity up into 12 groups or into 30 groups and the math would still have worked out pretty similarly. And in reality there are likely more groups than that - for example, even though they put together 282 global studies with nearly 6,000 genomes combined, I don't think they have any Australian aborigines in the sample, or the Andaman Islands, and they're probably missing other genetically unique groups as well.

But with the 21 group-division they ended up using because it was slightly more mathematically supportable than other groups, this is the ancestry tree they got:

Notice that it's not just a straight "tree", but that there were also multiple mixing events in ancient history that helped to form those groups.



However, it must be noted that these are not modern ethnic groups but rather ancient ancestries, ones that formed perhaps 10,000 years ago at the latest. In reality, modern people no matter where they live are a mix of multiple different ancient ancestries. Here are what their 6000 individuals from 282 ethnic samples look like with the different colors representing different ancestries.

Ancestry analysis of the global data set. The 282 samples are labeled alternating in the left and right margins. The 21 ancestral components are Kalash (black), Southern Asian (dark goldenrod), South Indian (slate blue), Central African (magenta), Southern African (dark orchid), West-Central African (brown), Western African (tomato), Eastern African (orange), Omotic (yellow), Northern African (purple), Northern European (blue), Southern European (dark olive green), Western Asian (white), Arabian (light gray), Oceanian (salmon), Japanese (red), Southeastern Asian (coral), Northern Asian (aquamarine), Sino-Tibetan (green), Circumpolar (pink), and Amerindian (gray).

That graphic is small and some of the names of the various ancestries are unclear, so I'm going to make more posts with clarifications.

 

[Professor Emeritus]

Since the names are sometimes a bit unclear, the authors listed the current ethnic group out of the ones tested that best matches each historical ancestry. In some cases there's a perfect match, but for most ancestries they found NO living group that still carries that ancestry 100%. Of course, as the genetics of more and more isolated aboriginal groups are tested, that may change.

Let me know if you have more representative pictures of any group, I did the best I can.



Here are the ancestries defined by the study and the group that best matches them today:


Karretjie (South Africa) are 100.0% "Southern African"

Mbuti Pygmy (Congo) are 100.0% "Central African"

Esan (southern Nigeria) are 66.3% "West-Central African"

Mandenka (Mali/Gambia/Guinea) are 89% "Western African"

Anuak (Ethiopia/Sudan/South Sudan) are 70.4% "Eastern African"

Aari Blacksmith (Ethiopia) are 97.3% "Omotic"

Nihali (west-central India) are 82% "South Indian"

Melanesians (Papua New Guinea, Fiji, Solomon Islands) are 100.0% "Oceanian"

Tibetans of the Tuo-Tuo River region (southwest China) are 89% "Sino-Tibetan"

Cambodians are 80% "Southeastern Asian"

Japanese are 91% "Japanese"

Yakut (Siberia) are 89% "Northern Asian"

Surui (Brazilian Amazon) are 100% "AmerIndian"

Greenlandic Inuit (East Greenland) are 94% "Circumpolar"

Kalash (Chitral district of Pakistan) are 100% "Kalash"

Brahui (western Pakistan and Afghanistan) are 54% "Southern Asian"

Abkhasian (south Caucus Mountains of Georgia) are 57% "Western Asian"

Basque (Pyrenees Mountains of Spain/France border) are 76% "Southern European"

Tunisians are 92% "Northern African"

Qataris are 85% "Arabian"

Finns are 79% "Northern European" [ran into photo limit so just imagine a really white Scandinavian person]




Note, again, that these are the LEAST "mixed" ancestries out of those 21 that are being used in the study. The vast majority of people on Earth are mixed between numerous different ones from this group.


For example, the typical Ethiopian Somali is 38% Eastern African, 30% Arabian, 23% Omotic, and 8% North African

The typical South Moroccan is 53% North African, 18% West African, 11% Southern European, 10% Arabian, 4% East African, 2% West-Central African, and 1% Omotic

The Burusho people of Pakistan are 34% Southern Asian, 25% South Indian, 11% Northern European, 9% Western Asian, 8% Sino-Tibetan, 8% Kalash, 2% AmerIndian, 1% Northern Asian, and 1% Oceanian

And the average Russian is 59% Northern European, 19% Southern European, 6% Western Asian, 6% Southern Asian, 5% Northern Asian, 2% Kalash, 1% Circumpolar, 1% AmerIndian, and 1% Arabian



A couple clarifications. These are generally NOT recent admixtures between modern ethnic groups, but usually represent the crossing of ancient ancestral lines many hundreds or thousands of years ago to produce the current ethnic groups. And the name of each ancestral group reflects its current region, but may not reflect its origin. For example, the AmerIndian group may have originated in Asia, the SinoTibetan group may have originated on Taiwan, the Oceanian group may have originated on mainland Asia, etc.

These also are NOT going to reflect the results that commericial programs like "23 and me" will give you. Those programs aren't as scientifically rigorous and are meant to reflect matching to modern populations, not analysis of ancient ancestry.

I'll do more breakdowns later, but just gonna sit on that for now.

 

[Professor Emeritus]

I wanted to make a general comment about genetic proximity before getting into more specifics.


First, I want to say again that the split into 21 ancestries isn't arbitrary, it was the mathematical best fit, but there were numerous other options that would have only made a small difference. If the paper authors had gone with 15 ancestries then some of the most closely-related ancestries would have ended up lumped together (like western african and west-central african, japanese and sino-tibetan, western asian and southern european), whereas if the paper authors had gone with 25 ancestries then some of the more diverse groups would have been split up further into new names. And that would change all the admixtures. The next paper someone writes on the same subject, possibly with thousands and thousands more genomes to work with from dozens or hundreds more ethnic groups, might give a different best fit number.

But we'll work with what we have, so we'll split human ancestry into those 21 main lines.


Now to genetic distance. Obviously, Africa was the origin of ancient humanity, as well as the origin of modern humans. As a result, there is more genetic diversity in Africa than in the rest of the world combined. The fact that there are more named ancestries outside Africa doesn't mean there's more diversity outside Africa, but just that those ancestries more easily split into differentiated groups because they had a lot more physical space to spread out over. But since those splits are more recent, the distance between them is relatively small and the overall genetic diversity is less. Whereas in Africa the splits are far older and the genetic distances and diversity far greater, but there aren't quite as many separated ancestries because African populations were too geographically close to fully differentiate into separate ancestries as many times.



For example, the Southern African ancestry, which is represented in the modern day by Khoi-San peoples who speak click languages (known to Europeans as "Bushmen" and Hottentots") split off from other groups in more ancient times than any other group, and thus is the most genetically unique ancestry on Earth. Its closest ancestral group is the Central African ancestry, which today is represented by the Mbenga and Mbuiti people of Congo and surrounding areas (known as "African pygmy" tribes). But the genetic distance between the Southern African ancestry and the Central African ancestry is large - to give you an idea, the genetic distance between the Northern European ancestry, the Southern Asian ancestry, and the North African ancestry is as small or smaller than the distance between Southern African and Central African ancestry. In total, Northern European ancestry has 6 other ancestries which are closer related to it than the Southern African ancestry is related to any ancestry.

Most of the other subsaharan african ancestries are closer to each other but still diverse - the distance between Western African ancestry and Eastern African ancestry is about the same as the difference between Northern European and Western Asian. The distance between Western African ancestry and Central African ancestry is about the same as the difference between Northern European and South Asian.

One other especially unique African ancestry is the "Omotic" group, which today is best represented by the Aari peoples of Ethiopia, and to a lesser extent the Wolayta of Ethiopia and Hadza of Tanzania. The fascinating aspect is that while the Omotic ancestry is not closely related to any other ancestry, it is somewhat related to a lot of other ancestries. Thus the distance between Omotic and Northern African ancestry is only slightly larger than the difference between Omotic and Central African ancestry, and the distance between Omotic and Arabian, Southern European, Western Asian, and South Asian ancestry is only a little bit larger than that. In the genetic mapping it appears that the Omotic line is actually the ancestry that all Northern African, Middle Eastern, European, Asian, and American ancestries branched off of.

In the diagram you can see that at some ancient time in history, the Eastern African and Omotic lines branched off of the Western/Central/Southern African line. That may have been well over 100,000 years ago. Then, perhaps 70,000 years ago, the lines that would form the rest of the world's ancestries branched off of that Omotic line - perhaps a particularly successful Omotic group migrated up over the Isthmus of Suez into the Middle East and began spreading across the globe, with different populations becoming genetically isolated in the different places they reached. Maybe that group had already long before moved up through Northern Africa, and that is how they had become genetically isolated from the other African ancestries in the first place.

Quick aside:

Spoiler

It's worth pointing out that this movement 70,000 years ago out of Africa was NOT the first one, it's just the one that lasted. The ancient human species Homo erectus may have first moved out of Africa about 2 million years ago, eventually spreading across Asia and giving rise to the "Denisovans" there. The ancient human species Homo heidelbergensis moved out of Africa and into Europe over a million years later, eventually giving rise to the "Neanderthals" there. Our own species Homo sapiens probably first moved out of Africa around 300,000 years ago but those populations didn't last, and that happened several more times before the movement out 70,000 years ago that soon wiped out the Denisovans and Neanderthals. By 40,000 years ago there were no Neanderthals left, around 15,000-20,000 years ago there were no Denisovans left either, and all the places they had lived were now full of modern Homo sapiens derived from the Omotic genetic line. But before they disappeared they interbred into the human line, and today all non-African persons have around 1-2% Neanderthal genes, while sub-saharan Africans have about 0.3% Neanderthal genes. Melanasians also have an additional 4-6% Denisovan genes and other Asians and Native Americans also have a small degree of Denisovan admixture. There also appears to be similarly significant admixture from archaic non-Homo sapiens humans throughout African populations, but the exact details are more difficult because we have no preserved DNA samples from these archaic African humans like we have from Denisovans and Neanderthals.

Looking at the graph again, besides the main ancestry trend of the black lines, you also see orange lines shooting their way across. Those are additional admixtures that occurred after those groups had split from each other, but before the final ancestral groups had formed. So you see that a migration of Omotic people came into the Middle East and remixed into the precursors of the Arab/Northern African/West Asian/Southern European groups, and then sometime later after those groups had split, a migration of Eastern African peoples mixed in to the precursors to the North Africans and formed the Northern African group. There was also a migration of the Northern European group at some point that mixed in with the precursors to the American Indian and Circumpolar group, likely in Siberia. Those three admixtures would have happened 20,000 years ago or more, most likely.



Of course, it bears repeating yet again that all of these genetic groups we are naming are ANCIENT genetic lines, not modern groups. Just because the Omotic line isn't closely related to any other line doesn't mean that the descendants of these Omotic peoples aren't related to others, because in reality many people across East Africa are 15-30% Omotic themselves. All that more recent admixture which is not shown in the chart would have happened in the last 5,000 years, after the ancient ancestry groups noted in the paper had already been formed. So even though two ancestries may be a long way apart on the line, there's been so much intermixture since then that their descendants are more closely related than the ancestors ever were.

 

[Professor Emeritus]

Let's get into the specifics. Africa comes first, literally.



This map shows where Southern African ancestry is found today. Each circle is a population where Southern African ancestry was detected, the darker the circle the more complete the ancestry in that population. This is one of the most genetically unique ancestries and not closely related to any other population, though it is slightly more closely related to Central African than to the others.

Notice today that this bloodline is almost entirely found in southern Africa. There are some traces in east Africa and barely discernible traces along the coast of west Africa. You can also see a trace among Black Americans in the South, we'll get to that later.

As I noted above, the Khoisan peoples of South Africa and Tanzania are the main representatives of this ancestry, with all the various Khoisan groups being anywhere from 40%-100% comprised of Southern African line. Interestingly, several "Coloured" groups from South African cities turn out to be 50-60% Southern African ancestry as well, suggesting quite a large migration of Khoisan people from their ancestral homes to the cities. Other south african groups like the Xhosa and south african Bantus are 20-25% Southern African, but the majority of those lines is West-Central African with input from Eastern African, Central African, and Western African.

Remember, just because the ancestry is concentrated in southern Africa today doesn't mean that it originated there. Many east African groups are 2-10% Southern African in ancestry. Is it possible that Southern African ancestry is an ancient East African line, but the groups there either died out or were pushed out and only the ones who migrated out to South Africa survived intact? Or does that Southern African ancestry in east Africa come from a minor migration of Southern Africans that settled in Ethiopia and eventually were absorbed into the population? That likely happened so long ago that archaeology and linguistics will have trouble answering it, though maybe the right fossilized DNA could reveal someday.




Central African ancestry is another fairly unique lineage, roughly equally related to Southern African, Western African, and West-Central African ancestries.

You can see there are only two groups that show primarily Central African ancestry - the Mbuti people of eastern Congo and the Biaka people of western Congo/Central African Republic, both of which are referred to as "Pygmy" tribes. Some other nearby pygmy tribes from the same two regions appear likely to have the same ancestry but were not tested here. There is also significant Central African ancestry among the Hadza people of Tanzania, and many nearby Bantu and other groups as well as some south African groups have 10-15% Central African ancestry, which could be a sign of early migration from Central African regions.



Western African and West-Central African are two very closely related lineages. Besides their very close relationship to each other, they are also fairly closely related to Eastern African ancestry, and a little bit less so to Central African and Omotic ancestries.

Western African ancestry is dominant among the Mande peoples of Guinea and the surrounding regions and to a lesser extent among the Brong of Ghana. To a small degree, Western African is also spread throughout west Africa and into other regions of Africa as well, likely as part of the Bantu expansion.

West-Central African ancestry is the majority ancestry among the Yoruba, Fang, and Bantu peoples, though all of those groups also have a significant amount of Western African ancestry as well as others. It has spread to eastern and southern Africa through the "Bantu expansion", an event around 5,000 years ago when Bantu-speaking people from West-Central Africa migrated to other regions of Africa and became the dominant people group in many places.

Both ancestries also have a degree of influence in the western side of North Africa, especially Morocco and to a lesser extent Algeria.

A study of 120 Black persons in Barbados found them to have 52% West-Central African ancestry and 40% Western African ancestry, along with 3% Central African and 1% each of Southern African, Omotic, Southern European, and Northern European.

A study of 62 unrelated Black persons (identify as African-American and had 4 African-American grandparents from the same area) from southwest USA found on average 37% Western African ancestry, 11% Central African ancestry, 9% West-Central African ancestry, 5% Southern African ancestry, 3% Omotic ancestry, and 2% Eastern African ancestry. They also averaged out to 20% Southern European, 8% Northern European, 2% Southern Asian, 2% Western Asian, and 0.3% Native American.




The Eastern African lineage is somewhat close to the Western African and West-Central African lineages, further from Omotic and much further from Southern African and Central African.

Eastern African ancestry is heavy in east Africa, but because so many other ancestries have influence there even the highest % for this ancestry is just 50-70%, which is found among various Sudanese groups. It is more like 25-40% in various Ethiopian, Kenyan, and Somali groups, and there is a significant amount of spread to the rest of Africa especially in Central African Republic and Chad.

This is also the first African ancestry to show influence in the middle east, with Eastern African ancestry comprising 6-8% of Egyptian and Yemeni ancestry and 1-2% of Jordanian and Lebanese.



Omotic is another unique lineage, not closely related to any other group. It is about equally distant from Eastern African, West-Central African, and Western African ancestries. The most fascinating thing is that despite being relatively far from other African ancestries, it is slightly closer to Eurasian ancestries than the others are, leading researchers to believe that all non-African groups originated from the Omotic ancestry.

The only people in the world with majority Omotic ancestry are the Aari people of Ethiopia (up to 97% Omotic in the Aari Blacksmith caste and 73% in the Aari Cultivator caste). It is around 46% of the ancestry of the Wolayta people of Ethiopia, 42% of the Hadza of Tanzania, and 20-30% of the ancestry of most other Ethiopian and Somali groups. Has a slight influence in Morocco and Egypt (1-2%) and Yemen (4%), but virtually no influence anywhere else in Africa.


It's fascinating that Omotic is the ancestry most closely related to Middle Eastern, European, and Asian groups, yet it has virtually no influence in any of them. That suggests that the ancestors of the Eurasian ancestries most closely related to Omotic (North Africans, Southern Europeans, Arabians, Western Asians, and South Indians) may have actually arisen within Africa first, and then moved out into the Middle East and beyond.



You might notice that there are some gaps that aren't covered in any of the maps. This study was the most comprehensive to date, testing 282 different ethnic groups with an average of over 20 sampled individuals per group. However, there are something like 5,000 different ethnic groups worldwide, meaning that many tribes were missed and in some cases entire regions. The more genetic sampling that is done, the better the picture will get.

 

[Professor Emeritus]

I want to cover a number of really unusual histories in the various African lines. But before I do that, let's follow the rest of the ancestries out quickly.


Now, it bears repeating that there's as much genetic diversity in Africa as in the rest of the world combined, which really kills the idea of "race" being any sort of objective biological category. For example, the Southern African ancestry and the Eastern African ancestry are as far apart as Northern European is from Japanese or Southeast Asian. In fact, Northern European and South Indian (the very dark ones) ancestries are CLOSER related than many African ancestries are to each other. That's basically because of our human species emerging for 300,000 years in Africa, so there has been a lot more time for lines to diverge and diversity to develop there, whereas the rest of the continents were only populated in the last 70,000 years.

So where did all those Eurasian ethnicities come from? As I said, the evidence points to a group emerging from the Omotic community and at some point moving north. From there they formed two main lines.

The first line developed into the South Indian and Oceanian ancestries, apparently moving along the coastal regions of the Indian Ocean. The questions here are fascinating. Did the South Indian line develop in Africa itself and only later move out? Or did Omotic people settle in South India and gradually diverge there? Or did it happen someplace in-between? Did they travel by land, or cross the oceans by very primtive boats? The fact that there isn't the slightest trace of these ancestries in any landmass between the Horn of Africa and South India suggests to me that they must have traveled by boat, first landing in southern India with one population settling there and becoming the South Indians, and others moving on to the Andaman Islands, Indonesia, New Guinea, Australia, etc. and becoming the various Oceanian groups. From the evidence it appears that the Sino-Tibetan, Southeastern Asian, Japanese, Northern Asian, Circumpolar, and American Indian ancestries all later came from these lines.

The second line, perhaps at the same time or perhaps somewhat later, seems to have moved by land rather than by sea, traveling up through Egypt to the Mediterranean region. Once again the question remains - were these Omotic peoples moving up who only later diverged genetically, or had they already diverged into separate populations and then moved later? And when they did diverge, did it happen in Egypt, or much later? It may be impossible to know. But what does appear to have happened is that by some process one group of Omotic-descendants ended up traveling north then east overland and becoming the Kalash and Southern Asian ancestries (basically Pakistan and Afghanistan areas), while the other moved north then west and diverging into the Northern European, Arabian, Western Asian, Southern European, and Northern African ancestries. Again, did the Northern African ancestry diverge off of these Omotic descendants inside of Africa and move west, or did they diverge much later in the Middle East, Western Asian, or Europe, and then return and populate Northern Africa? Once again, really tough to know.

But there are two other critical events that we do seem to be able to know from the genetic record that are important.

First, before the Arabian, Northern African, Western Asian, and Southern European lines split from each other (but after the Northern European line had already split off), there was a major mixing even between that line and the original Omotic line. How did this happen? Is it possible that that line hadn't even left East Africa yet and it was a local event? Or perhaps they had left, but hadn't left Africa, and a migration of Omotic peoples north joined their people? Or did it somehow happen outside Africa due to a new major "out of Africa" migration?

The second event was after those groups had mostly split, the Northern African line seems to have formed via a second admixture event with the Eastern African line. That event isn't quite as big a mystery - due to how late it was, it seems almost certain that some Eastern Africans were populating Northern Africa at the same time that the Omotic-derived line was, and the two lines mixed to form the Northern African ancestry.

Remember, all this shyt happened BEFORE we start talking about any of the mixtures discussed in modern ethnic groups. This isn't how the ancestries mixed, but how they formed in the very first place, starting over 100,000 years ago for the first six African ancestries and around 70,000 or so years ago for the out-of-Africa ancestries, and not becoming fully formed into the 21 ancestries we're discussing until perhaps 6,000-7,000 years ago.

Of course, even though these near-arbitrary 21 ancestries had fully formed by 4500 B.C. or so, that doesn't mean people stopped migrating and mixing. And thus stuff gets really surprising.

 

[Professor Emeritus]

The Malagasy people are quite unique in Africa. Looking at them, they almost look a bit....Blasian

And the language they speak, Malagasy, is...from the Malayo-Polynesian branch of Austronesian? And their architecture is the same as in Borneo? And their musical instruments are the same as those in Borneo?

Crazy as it is to believe, genetic studies prove that the island of Madagascar was first settled by the Banjar people of Borneo, who came west on a ship from over 4,000 miles away to settle Madagascar just like they ended up settling islands even further away across the entire southern Pacific Ocean.


The blue regions show the areas of Austronesian colonization, long after the Oceanian ancestry had become distinct:

The archaeological evidence suggests that this Oceanian-background people arrived in Madagascar around 500 A.D. and found it unpopulated, like most of the islands they had settled in. That seems bizarre, but remember that Madagascar is 250 miles from the African mainland, far too distant to be seen by any reasonable fishing boat, and unlike the seafaring Austroasians, the African people with a whole continent to live in had no reason to just blindly push out into the ocean hoping to run into something. So Madagascar had remained unoccupied until the people from Borneo found it.

Also, the South Equatorial Current runs from Indonesia to Madagascar, so the boat may have simply drifted all the way there. However, that would have taken 6 months, which would have been a mind-blowing length of time to survive at sea in that era.

Genetic studies suggest that the original population was quite small - possibly just 30 women from Borneo were the ancestors of all Malagasy. That means it might have been a one-off event rather than a planned migration - one large ship drifting to the island, with 30-40 women and an unknown number of men. Trade vessels didn't tend to have so any women, so it is hypothesized that perhaps it was a refugee ship, forced to leave their own island due to conflict or natural disaster, and ended up on Madagascar, quite possibly by complete accident. With abundant resources and no one else around, their numbers increased rapidly.

Around 800 years ago, Bantu peoples from South Africa came across the ocean to Madagascar and began mixing with the Borneo-origin population. Today, DNA studies show that Malagasy people are anywhere from 35-75% Bantu origin and 15-55% Borneo origin, with the remainder being East African, Arab, and West Asian influence from Swahilli and Muslim settlement on the island. The most highly Asian groups are in the middle highlands of the island, and the most highly African groups are around the coastal regions, but all Malagasy are some mix of both ancestries. The Bantu genetics dominate on the Y-chromosome and are much lesser in mitochondrial DNA (which is spread from mothers to children). That suggests that the majority of Bantus who came over and settled on the island were men. The Malagasy language is approximately 90% Austronesian and just 10% Bantu in origin. That's likely due to the fact that the Austronesians were already settled on the island first, so the Bantu gradually acculturated into their language moreso than the other way around.

Spoiler

While the genetic and cultural background of the Malagasy people appears to not be in any doubt, the biggest open question is "when did it happen?" Madagascar is a hot wet climate that doesn't lend itself to preservation of artifacts, and the seafaring Austronesians built almost everything out of wood which just plain doesn't last that long. So it's really hard to trace exactly when the island was first settled, and most of the deduction is inferred from the genetic studies, which aren't exact when it comes to tracing timespans rather than simple admixtures. Some of the sources I read thought it happened 2000 years ago, and some said 1500 years ago, and a few thought it was just 900 or so years ago. They appeared to agree more definitively that the Bantu groups arrived about 800 years ago.

 

[null]

as a start:

as these groups spread out from Africa they interbred with "archaic" populations which were already there and which may or may not have themselves developed (sapianized) within africa. off the top of my head erectus was outside of africa over 1 million years ago. surely erectus genetically drifted within those million plus years.

also post these departures (and sometimes even prior) african populations have at least in isolated pockets interbred with local archaic populations which no longer exist.

where are (all of) these factors taken into account in the above discussion?

in limiting the time for drift to the period of these populations original departure from africa is that not ignoring the time of drift within the archaic populations that they met with and bred with outside of Africa.

neanderthals. denosovians. and other archaic african populations (i'm not aware of the names but links below).



https://www.sci.news/genetics/west-africans-dna-archaic-hominin-08123.html

https://www.pnas.org/doi/10.1073/pnas.1109300108

 

[Secure Da Bag]

Japanese are 91% "Japanese"

Interesting I'd thought that would be more like "91% SE Asian" or something. Didn't the Japanese emigrate from China?

 

[Professor Emeritus]

as a start:

as these groups spread out from Africa they interbred with "archaic" populations which were already there and which may or may not have themselves developed (sapianized) within africa. off the top of my head erectus was outside of africa over 1 million years ago. surely erectus genetically drifted within those million plus years.

also post these departures (and sometimes even prior) african populations have at least in isolated pockets interbred with local archaic populations which no longer exist.

where are (all of) these factors taken into account in the above discussion?

The Neanderthal and Denisovan admixtures are mentioned in the 3rd post in the thread, you may have missed it because I put it in a spoiler:

Quick aside:

Spoiler

It's worth pointing out that this movement 70,000 years ago out of Africa was NOT the first one, it's just the one that lasted. The ancient human species Homo erectus may have first moved out of Africa about 2 million years ago, eventually spreading across Asia and giving rise to the "Denisovans" there. The ancient human species Homo heidelbergensis moved out of Africa and into Europe over a million years later, eventually giving rise to the "Neanderthals" there. Our own species Homo sapiens probably first moved out of Africa around 300,000 years ago but those populations didn't last, and that happened several more times before the movement out 70,000 years ago that soon wiped out the Denisovans and Neanderthals. By 40,000 years ago there were no Neanderthals left, around 15,000-20,000 years ago there were no Denisovans left either, and all the places they had lived were now full of modern Homo sapiens derived from the Omotic genetic line. But before they disappeared they interbred into the human line, and today all non-African persons have around 1-2% Neanderthal genes, while sub-saharan Africans have about 0.3% Neanderthal genes. Melanasians also have an additional 4-6% Denisovan genes and other Asians and Native Americans also have a small degree of Denisovan admixture.

I didn't include anything on other archaic groups in Africa, I had heard of that before but looked for it briefly when I made the post and couldn't find it so I left it out. I'll check your papers and add in anything noteworthy I find.

But yes, the study above is only following the trace of Homo sapiens ancestries, they're not showing the trace of outside admixture in the charts.

 

[Professor Emeritus]

Interesting I'd thought that would be more like "91% SE Asian" or something. Didn't the Japanese emigrate from China?

Remember, the names of the ancestries are just based on their current loci, they're not trying to guess where each population originated. That ancestry is called "Japanese" because it's most highly represented today in Japan, but archaeological and genetic evidence shows that Japan was first populated from China about 16,000 years ago, and even those early genetics were mostly knocked out of modern Japanese people by another group that mostly came from China just a few thousand years ago. And many people groups in east/northeast China are around 40% derived from the "Japanese" ancestry, which in my mind is more likely to come from that population already being present in China rather than some massive exodus of Japanese people from the island of Japan. So the "origin" of the Japanese ancestry group is almost certainly somewhere in east Asia, before those people moved into Japan, and just got diluted on the mainland by other groups moving across the continent.

Here are the maps of the main ancestries in that region (ignoring for the moment Circumpolar, AmerIndian, Northern European, Southern Asian, and Oceanian which all have their own degree of admixture in eastern Asia as well).

The Japanese, Sino-Tibetan, and Southeastern Asian ancestries are all extremely closely related, possibly having diverged just in the last 10,000 years. Whereas the Northern Asian, Circumpolar, and American Indian ancestries form their own somewhat further removed clump that would have to have diverged from the others before modern Native Americans crossed the land bridge into the Americas. And the South Indian and Oceanian ancestries diverged away from the others in the region earlier than that.

Besides a large degree of Northern European admixture throughout much of the Asian continent which appears to be quite ancient (i.e. - why there are basically white tribal groups in Russia even quite far to the east), one of the most interesting things in the mix in Asia is the Southern Asian ancestry which is dominant in Pakistan, Afghanistan, and north India but which has some influence all the way from China to throughout western Europe. This ancestry is part of the western side of that early divergence and turns out to be one of the most unique ancestries in Eurasia. While not particularly closely related to any group, it's about equally related to Kalash, Western Asian, and Northern European ancestries.

 

[RageKage]

We can learn a lot about how people migrated & lived during the time we have no written history by studying human genes.