Prehistoric Human Migrations

[lpetrich]

Neolithic and Bronze Age migration to Ireland and establishment of the insular Atlantic genome | PNAS

The first ancient whole genomes from Ireland, including two at high coverage, demonstrate that large-scale genetic shifts accompanied both transitions. We also observe a strong signal of continuity between modern day Irish populations and the Bronze Age individuals, one of whom is a carrier for the C282Y hemochromatosis mutation, which has its highest frequencies in Ireland today.

The Neolithic and Bronze Age transitions were profound cultural shifts catalyzed in parts of Europe by migrations, first of early farmers from the Near East and then Bronze Age herders from the Pontic Steppe. However, a decades-long, unresolved controversy is whether population change or cultural adoption occurred at the Atlantic edge, within the British Isles. We address this issue by using the first whole genome data from prehistoric Irish individuals. A Neolithic woman (3343–3020 cal BC) from a megalithic burial (10.3× coverage) possessed a genome of predominantly Near Eastern origin. She had some hunter–gatherer ancestry but belonged to a population of large effective size, suggesting a substantial influx of early farmers to the island. Three Bronze Age individuals from Rathlin Island (2026–1534 cal BC), including one high coverage (10.5×) genome, showed substantial Steppe genetic heritage indicating that the European population upheavals of the third millennium manifested all of the way from southern Siberia to the western ocean. This turnover invites the possibility of accompanying introduction of Indo-European, perhaps early Celtic, language. Irish Bronze Age haplotypic similarity is strongest within modern Irish, Scottish, and Welsh populations, and several important genetic variants that today show maximal or very high frequencies in Ireland appear at this horizon. These include those coding for lactase persistence, blue eye color, Y chromosome R1b haplotypes, and the hemochromatosis C282Y allele; to our knowledge, the first detection of a known Mendelian disease variant in prehistory. These findings together suggest the establishment of central attributes of the Irish genome 4,000 y ago.

So the people of Ireland are much like the rest of Europe's human populations, an overlay of Paleolithic, Neolithic, and steppe migrants, with not much change since then.

 

[lpetrich]

Thousands of horsemen may have swept into Bronze Age Europe, transforming the local population | Science | AAAS

Call it an ancient thousand man march. Early Bronze Age men from the vast grasslands of the Eurasian steppe swept into Europe on horseback about 5000 years ago—and may have left most women behind. This mostly male migration may have persisted for several generations, sending men into the arms of European women who interbred with them, and leaving a lasting impact on the genomes of living Europeans.

"It looks like males migrating in war, with horses and wagons," says lead author and population geneticist Mattias Jakobsson of Uppsala University in Sweden.

noting
Nomadic herders left a strong genetic mark on Europeans and Asians | Science | AAAS
Back to the original article.

Europeans who were alive from before the Yamnaya migration inherited equal amounts of DNA from Anatolian farmers on their X chromosome and their autosomes, the team reports today in the Proceedings of the National Academy of Sciences. This means roughly equal numbers of men and women took part in the migration of Anatolian farmers into Europe.

But when the researchers looked at the DNA later Europeans inherited from the Yamnaya, they found that Bronze Age Europeans had far less Yamnaya DNA on their X than on their other chromosomes. Using a statistical method developed by graduate student Amy Goldberg in the lab of population geneticist Noah Rosenberg at Stanford University in Palo Alto, California, the team calculated that there were perhaps 10 men for every woman in the migration of Yamnaya men to Europe (with a range of five to 14 migrating men for every woman). That ratio is "extreme"—even more lopsided than the mostly male wave of Spanish conquistadores who came by ship to the Americas in the late 1500s, Goldberg says.

 

[lpetrich]

Unraveling ancestry, kinship, and violence in a Late Neolithic mass grave | PNAS

We sequenced the genomes of 15 skeletons from a 5,000-y-old mass grave in Poland associated with the Globular Amphora culture. All individuals had been brutally killed by blows to the head, but buried with great care. Genome-wide analyses demonstrate that this was a large extended family and that the people who buried them knew them well: mothers are buried with their children, and siblings next to each other. From a population genetic viewpoint, the individuals are clearly distinct from neighboring Corded Ware groups because of their lack of steppe-related ancestry. Although the reason for the massacre is unknown, it is possible that it was connected with the expansion of Corded Ware groups, which may have resulted in violent conflict.

Oof. I'm at a loss for words.

Genomic Steppe ancestry in skeletons from the Neolithic Single Grave Culture in Denmark

The Gjerrild burial provides the largest and best-preserved assemblage of human skeletal material presently known from the Single Grave Culture (SGC) in Denmark. For generations it has been debated among archaeologists if the appearance of this archaeological complex represents a continuation of the previous Neolithic communities, or was facilitated by incoming migrants. We sampled and analysed five skeletons from the Gjerrild cist, buried over a period of c. 300 years, 2600/2500–2200 cal BCE. Despite poor DNA preservation, we managed to sequence the genome (>1X) of one individual and the partial genomes (0.007X and 0.02X) of another two individuals. Our genetic data document a female (Gjerrild 1) and two males (Gjerrild 5 + 8), harbouring typical Neolithic K2a and HV0 mtDNA haplogroups, but also a rare basal variant of the R1b1 Y-chromosomal haplogroup. Genome-wide analyses demonstrate that these people had a significant Yamnaya-derived (i.e. steppe) ancestry component and a close genetic resemblance to the Corded Ware (and related) groups that were present in large parts of Northern and Central Europe at the time. Assuming that the Gjerrild skeletons are genetically representative of the population of the SGC in broader terms, the transition from the local Neolithic Funnel Beaker Culture (TRB) to SGC is not characterized by demographic continuity. Rather, the emergence of SGC in Denmark was part of the Late Neolithic and Early Bronze Age population expansion that swept across the European continent in the 3rd millennium BCE, resulting in various degrees of genetic replacement and admixture processes with previous Neolithic populations.

More evidence that northern Europeans are largely descended from Yamnaya people, the third wave of prehistoric human migration into Europe. The previous ones were the Paleolithic and the Neolithic-farmer ones.

 

[lpetrich]

A three-population wave-of-advance model for the European early Neolithic
Contains a numerical simulation of the advance of Neolithic farmers. The three populations are the previously-present hunter-gatherers, the initial population of Neolithic farmers in their Anatolian homeland, and hunter-gatherers who learned farming from their farmer neighbors. They get a good fit to what is observed -- farming spreading with farmers moving in -- by finding that the hunter-gatherers did not often learn farming from their farming neighbors.

n order that the model described in this paper apply to the Neolithic transition in Europe, the conversion rate of hunter-gatherers to farming must be low. An ethnological study shows that hunter-gatherers may have profitably coexisted with farmers, for example by trading animal protein and labor for carbohydrates and “luxury” items [38]. An archaeological study of central and western Europe shows that farmers of the Linearbandkeramik culture and hunter-gatherers may have coexisted by spatial exclusion: “People of the LBK settled in exactly those areas only marginally exploited by hunter-gatherers and not … with … more intense hunter-gatherers exploitation” [39]. A definitive study combines information from ancient DNA and dietary stable isotope data to show “persuasive evidence for the prolonged coexistence of genetically distinct hunter-gatherers and farming groups over the course of the Neolithic in Central Europe” [7]. Thus, various lines of evidence argue against the ready conversion of hunter-gatherers to farming. Moreover, Bowles [40] compares the productivity of foraging with early farming and concludes that, if hunter-gatherers converted to farming, they did not do so “because cultivation of crops was simply a better way to make a living.” The motivation for conversion may have been social competition, perhaps for marriage partners [41]. Prolonged coexistence provides opportunities for conversion, but also entails day-to-day competition unless there is active avoidance.

The spatiotemporal spread of human migrations during the European Holocene | PNAS

We present a study to model the spread of ancestry in ancient genomes through time and space and a geostatistical framework for comparing human migrations and land-cover changes, while accounting for changes in climate. We show that the two major migrations during the European Holocene had different spatiotemporal structures and expansion rates. In addition, we find that the Yamnaya expansion had a stronger association with vegetational landscape changes than the earlier Neolithic farmer expansion.

... We find that the spread of Neolithic farmer ancestry had a two-pronged wavefront, in agreement with similar findings on the cultural spread of farming from radiocarbon-dated archaeological sites. This movement, however, did not have a strong association with changes in the vegetational landscape. In contrast, the Yamnaya migration speed was at least twice as fast and coincided with a reduction in the amount of broad-leaf forest and an increase in the amount of pasture and natural grasslands in the continent.

Remember that correlation != causation. Did the Yamnaya people take advantage of droughts? Or did they clear lots of forests to make fields for their cows and horses to graze in?

 

[lpetrich]

Dairying enabled Early Bronze Age Yamnaya steppe expansions | Nature

During the Early Bronze Age, populations of the western Eurasian steppe expanded across an immense area of northern Eurasia. Combined archaeological and genetic evidence supports widespread Early Bronze Age population movements out of the Pontic–Caspian steppe that resulted in gene flow across vast distances, linking populations of Yamnaya pastoralists in Scandinavia with pastoral populations (known as the Afanasievo) far to the east in the Altai Mountains1,2 and Mongolia3. Although some models hold that this expansion was the outcome of a newly mobile pastoral economy characterized by horse traction, bulk wagon transport4,5,6 and regular dietary dependence on meat and milk5, hard evidence for these economic features has not been found. Here we draw on proteomic analysis of dental calculus from individuals from the western Eurasian steppe to demonstrate a major transition in dairying at the start of the Bronze Age. The rapid onset of ubiquitous dairying at a point in time when steppe populations are known to have begun dispersing offers critical insight into a key catalyst of steppe mobility. The identification of horse milk proteins also indicates horse domestication by the Early Bronze Age, which provides support for its role in steppe dispersals. Our results point to a potential epicentre for horse domestication in the Pontic–Caspian steppe by the third millennium bc, and offer strong support for the notion that the novel exploitation of secondary animal products was a key driver of the expansions of Eurasian steppe pastoralists by the Early Bronze Age.

Dental calculus = hard crusty deposits on teeth. These deposits trapped milk proteins, which were analyzed by the researchers. Proteins have amino-acid sequences that can be used to identify the species of their makers, and in this case, the milk proteins were identified as coming from horses. So these people milked horses.

J.P. Mallory in "In Search of the Indo-Europeans" notes that around 1900, many archeologists rather indiscriminately posited migraions. But by 1950, the tide of opinion had turned the other way, to what some archeologists called "immobilism", people staying fixed in place and instead learning things from their neighbors. Pots != people, they warn.

But with genetic evidence, we can test hypotheses of prehistoric migrations, and we find evidence of them. It's like catastrophism in geology. Catastrophist hypotheses were common in early 19th cy. geology, but they were discredited by the mid 19th cy., likely because they were poorly-defined hypotheses. Uniformitarianism became geological orthodoxy, and there was indeed a lot of evidence for uniformity. Catastrophism has made a comeback over the last half-century to last century, because of better ability to test hypotheses of catastrophes, like asteroid impacts. Furthermore, it's not catastrophes vs. uniformity. There continue to be oodles of evidence for approximate uniformity in the geological record.

 

[Swammerdami]

J.P. Mallory in "In Search of the Indo-Europeans" notes that around 1900, many archeologists rather indiscriminately posited migraions. But by 1950, the tide of opinion had turned the other way, to what some archeologists called "immobilism", people staying fixed in place and instead learning things from their neighbors. Pots != people, they warn.

But with genetic evidence, we can test hypotheses of prehistoric migrations, and we find evidence of them. It's like catastrophism in geology....

There were two major initial migrations into Western Europe of farmers beginning near Greece. The Linear Ware (or Danubian) culture noted for its longhouses, traveled up the Danube beginning about 5500 BC, and then down the Rhine reaching the English Channel about 4500 BC. This was a combination of "pots" and people, with the farmers' DNA gradually diluted with DNA of hunter-gatherers who adopted farming. Y-haplogroup I2, which came to Europe with the Solutreans, was dominant among these people.

The second major influx was Impressed Ware (later Cardial Ware) and followed the (northern) Mediterranean coast from Greece and Italy all the way to Gibraltar and a bit beyond, with dates roughly similar to those of Linear Ware. But rather than traveling over-land, some suppose that these were an adventurous sea-faring people, who hop-scotched along the coast. They may have kept their DNA "purer" than Linear Ware did. One of their main Y-haplogroups was G2a2a-PF3147. This is the haplogroup of Ötzi, the famous 5200 year-old mummy found dead of an arrow wound in the Alps. (Although common among ancient skeletons, that haplogroup is almost missing from Western Europe today except in isolated areas like Sardinia. Most G's in Western Europe today are in G2a2b2 and thought to descend from the Alans who migrated westward as the Roman Empire collapsed.

But the overwhelming majority of Y-chromosomes in Europe today are R1a or R1b, and descend from the Indo-European speakers. Texts that describe Bell Beaker (or Corded Ware) as an invasion of "pots" rather than people, are vividly shown to be false. The rate at which these people (Bell Beaker in particular) multiplied is stupendous. Did these invaders indulge in genocide? Or was the Western European population already decimated by famine or epidemic? (Probably both were involved.) I've attached a clading diagram of the Y-chromosome suggesting the rapidity of the Indo-European expansions. (P312-S116 is Bell Beaker.)

P312 himself — for that mutation did occur in one specific man, presumably a Yamnayan prince whose ancestors had recently moved west — lived about 2500 BC. With the clading diagram now available in great detail, one can ALMOST guess the lineages from P312 to historic Kings like Niall of Ireland, Alfred of England, or Charlemagne.

 

[lpetrich]

3,000 Years Ago, Britain Got Half Its Genes From France, DNA Study Suggests - The New York Times
"An extensive study of ancient DNA suggests that a wave of newcomers — and perhaps the first Celtic languages — crossed the English Channel three millenniums ago."

The Beaker phenomenon and the genomic transformation of northwest Europe | Nature - from 2018

From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britain’s gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries.

Large-scale migration into Britain during the Middle to Late Bronze Age | Nature - most recently

Present-day people from England and Wales harbour more ancestry derived from Early European Farmers (EEF) than people of the Early Bronze Age1. To understand this, we generated genome-wide data from 793 individuals, increasing data from the Middle to Late Bronze and Iron Age in Britain by 12-fold, and Western and Central Europe by 3.5-fold. Between 1000 and 875 bc, EEF ancestry increased in southern Britain (England and Wales) but not northern Britain (Scotland) due to incorporation of migrants who arrived at this time and over previous centuries, and who were genetically most similar to ancient individuals from France. These migrants contributed about half the ancestry of Iron Age people of England and Wales, thereby creating a plausible vector for the spread of early Celtic languages into Britain. These patterns are part of a broader trend of EEF ancestry becoming more similar across central and western Europe in the Middle to Late Bronze Age, coincident with archaeological evidence of intensified cultural exchange2–6. There was comparatively less gene flow from continental Europe during the Iron Age, and Britain’s independent genetic trajectory is also reflected in the rise of the allele conferring lactase persistence to ~50% by this time compared to ~7% in central Europe where it rose rapidly in frequency only a millennium later. This suggests that dairy products were used in qualitatively different ways in Britain and in central Europe over this period.

 

[lpetrich]

Ian Armit, an archaeologist at the University of York who collaborated on the research, noted that archaeologists had long known about the trade and exchanges across the English Channel during the Middle to Late Bronze Age. “But while we may once have thought that long-distance mobility was restricted to a few individuals, such as traders or small bands of warriors,” he said, “the new DNA evidence shows that considerable numbers of people were moving, across the whole spectrum of society.”

Lara Cassidy, a geneticist at Trinity College Dublin who was not involved in the research, described the study as “a triumph. It takes a step back and considers Bronze Age Britain on the macro scale, charting major movements of people over centuries that likely had profound cultural and linguistic consequences.”

Where did the Celts emerge from?

For most of the 20th century, the standard theory, “Celtic from the East,” held that the language started around Austria and southern Germany sometime around 750 B.C. and was taken north and west by Iron Age warriors. An alternative theory, “Celtic from the West,” saw Celtic speakers fanning out from the Atlantic seaboard of Europe, perhaps arising in the Iberian Peninsula or farther north, and settling in Britain by as long ago as 2,500 B.C.

In 2020, Dr. Sims-Williams published a third theory, “Celtic from the Centre,” in the Cambridge Archaeological Journal. His premise was that the Celtic language originated in the general area of France in the Bronze Age, before 1,000 B.C., and then spread across the English Channel to Britain in the Late Bronze Age and Early Iron Age.

Did Celtic speakers go to Ireland straight from the mainland? Or did they cross over from Great Britain?

Wherever they originated, they also spread over much of the rest of Europe, though they later disappeared into the local populations of many places.

The closest relative of the Celtic family of Indo-European is the Italic family, though the possible existence of an Italo-Celtic group has been a contentious issue for a long time. Italic's best-known members are Latin and its descendants, the Romance languages. But there were other ancient members of Italic, like Faliscan, Oscan, and Umbrian, spoken in Italy in the 1st millennium BCE.

Finally,

The milk of Neolithic kindness

By leveraging their large data set of ancient DNA, Dr. Reich and his colleagues also found that lactase persistence — the ability of adults to digest the sugar lactose in milk — increased 1,000 years earlier in Britain than in Central Europe. At the dawn of the Iron Age, Dr. Reich said, overall lactase persistence on the island was about 50 percent, compared to less than 10 percent in the region stretching from the Baltic Sea to the Adriatic.

Curiously, analysis of the hardened dental plaque coating ancient teeth, and of traces of fat and protein left on ancient pots, showed that dairy products were a dietary staple in Britain thousands of years before lactase persistence became a common genetic trait.

“Either Europeans tolerated stomachaches prior to the genetic changes or, perhaps more likely, they consumed processed dairy products like yogurt or cheese where the lactose content has been significantly reduced through fermentation,” Dr. Reich said.

Paul Pettitt, a Paleolithic archaeologist at Durham University, said, “The results sound fascinating, although in terms of what drink the English adapted to before their continental neighbors, it amazes me that it’s not beer.”

 

[Swammerdami]

The attested Celtic languages divide roughly into four groups: Q-Celtic [Celtiberian] in Spain, P-Celtic in the Continent east of Spain, Q-Celtic in Ireland (and its Scots colony), and P-Celtic in Britain (and eventually Brittany). Note that the two P- groups are adjacent to each other, as are the two Q's, the two Insulars and the two Continentals.

Some say the uppermost split in Celtic was between Continental and Insular; others that it was between Q and P. Some say the splitting began early in the Bronze Age; others that the splitting was a response to the expansion of the Hallstatt Iron Age more than a millennium later.

I think all four theories are correct!

The Bell Beaker warriors, whose population expanded rapidly a few centuries before the sudden eruption of bronze usage in Western Europe, most probably spoke a language — call it pre-Celtic — ancestral to the Celtic family. These people were fast moving and quickly came to dominate lands they conquered; I've previously mentioned that a man ["Amesbury Archer"] who might be a grandson of P312 himself and who was born near the Alps is buried in a place of honor in pre-Bronze^* Stonehenge.

Did these Bell Beaker conquerors have good ocean navigation? I think they traveled across the Bay of Biscay from Spain to Brittany or Ireland. What's the evidence? Did they ride on horseback? They surely had animal-drawn wagons, but archaeological evidence may be meager. Experts? In any event, it seems fair to assume the people, or at least their elites, did much travel during the Bronze Age throughout the large Bell Beaker domains.

Therefore these people, the pre-Celts, frequently came in contact with other pre-Celtic people who spoke either a language intelligible to their own, or which was easily learned. Rather than splitting up along a definite tree model, the pre-Celtic dialects evolved via contact. Just as present-day dialects in Northern England retain traits of Old Norse [cite?], so the Insular language of Ireland retains traits (e.g. the Q sound) from its Bronze Age contacts with Spain.

* - Even Wikipedia doesn't agree with itself about when Britain entered "the Bronze Age." Amesbury Archer's tomb is described as "Early Bronze Age" despite having zero bronze artifacts [cite?]. The discovery of tin in Cornwall may have been 2100 BC but with big error bars. And: Do experts use the term "Bronze Age" to involve something other than the use of bronze?

 

[lpetrich]

Khoisan hunter-gatherers have been the largest population throughout most of modern-human demographic history | Nature Communications

The Khoisan people from Southern Africa maintained ancient lifestyles as hunter-gatherers or pastoralists up to modern times, though little else is known about their early history. Here we infer early demographic histories of modern humans using whole-genome sequences of five Khoisan individuals and one Bantu speaker. Comparison with a 420 K SNP data set from worldwide individuals demonstrates that two of the Khoisan genomes from the Ju/’hoansi population contain exclusive Khoisan ancestry. Coalescent analysis shows that the Khoisan and their ancestors have been the largest populations since their split with the non-Khoisan population ~100–150 kyr ago. In contrast, the ancestors of the non-Khoisan groups, including Bantu-speakers and non-Africans, experienced population declines after the split and lost more than half of their genetic diversity. Paleoclimate records indicate that the precipitation in southern Africa increased ~80–100 kyr ago while west-central Africa became drier. We hypothesize that these climate differences might be related to the divergent-ancient histories among human populations.

So the largest early modern-human population was in Southern Africa before the dispersal into Eurasia and the Americas.

African mitochondrial haplogroup L7: a 100,000-year-old maternal human lineage discovered through reassessment and new sequencing | Scientific Reports
Originally interpreted as part of L0 to L6, it is closest to L5. The oldest divergence in the L's was about 140,000 years ago.

he earliest modern human population divergences are thought to include: (1) foraging peoples from the ancestors of non-foraging peoples by ~ 160 kya, and (2) Khoisan from other foragers such as RFHGs and Hadza and Sandawe ancestors by ~ 120–100 kya26,27. Subsequent divisions between Niger-Congo, Nilo-Saharan, and Afro-Asiatic lineages and between eastern and western branches of Khoisan and RFHGs occurred less than 55 kya. Modern-day populations such as Hadza and Sandawe illustrate the complexity that ensued: after a ~ 88 kya split from each other, they admixed with Afro-Asiatic groups such as Omotic and Cushitic, and with the Khoisan from whom they likely derive their click-language110. Gradual population growth followed by several major demographic expansions in the Middle Stone Age ~ 75–55 kya35,111,112,113 were the likely catalysts for advancing new terrestrial and marine foraging abilities, microlithic technology, novel pigments in art, and possibly even syntactic language114,115,116,117,118,119. Although most African populations retain a genetic signal of expansion from ~ 70 kya or as early as ~ 110 kya in East African Nilotic groups, serial bottlenecks have largely erased this expansion signal from hunter-gatherer groups120.

RFHG = rainforest hunter-gatherers

Such oscillating periods of population divergence followed by major expansion events with admixture between groups may reflect episodic climatic change across the continent. During glacial maxima, reduced forestation has resulted from increased aridity and desertification, restricting humans to lakeshores, river margins, oceansides, and highlands of Kenya and Ethiopia with persistent canopy cover121. Such oases of habitat may have been important refugia during the arid OIS 6 period from ~ 200–125 kya, if woodland habitat was favored by humans as a source of water, food, and protection from heat and predation. Archaeological and climatic evidence suggests an improvement after this period, however East and tropical Central Africa show inverse population abundances, especially from 130–60 kya, with an increase in Central Africa and a decrease in East Africa122. Changing monsoonal patterns caused wet periods in East Africa during 145–120, 110–95, 80–65, and 55–50 kya, and simultaneous arid periods in Central Africa, including a “megadrought” from 115 to 90 kya122,123,124. Volcanic activity caused by a series of caldera collapses along the Eastern African Rift System also likely made the region uninhabitable for segments of time122. Thus, asynchronous pulses of climatic and tectonic instability125 likely forced human dispersals back and forth across the African continent during much of prehistory.

Yet more evidence that we are all mutts.

 

[lpetrich]

A weakly structured stem for human origins in Africa | Nature

We infer a reticulated African population history in which present-day population structure dates back to Marine Isotope Stage 5. The earliest population divergence among contemporary populations occurred 120,000 to 135,000 years ago and was preceded by links between two or more weakly differentiated ancestral Homo populations connected by gene flow over hundreds of thousands of years. Such weakly structured stem models explain patterns of polymorphism that had previously been attributed to contributions from archaic hominins in Africa2,3,4,5,6,7.

 Marine Isotope Stage 5

Marine Isotope Stage 5 or MIS 5 is a marine isotope stage in the geologic temperature record, between 130,000 and 80,000 years ago.[1] Sub-stage MIS 5e, called the Eemian or Ipswichian, covers the last major interglacial period before the Holocene, which extends to the present day.[2]

I've seen a lot of news stories about this discovery of two early-modern-human populations.

Ancient West African foragers in the context of African population history | Nature

Our knowledge of ancient human population structure in sub-Saharan Africa, particularly prior to the advent of food production, remains limited. Here we report genome-wide DNA data from four children—two of whom were buried approximately 8,000 years ago and two 3,000 years ago—from Shum Laka (Cameroon), one of the earliest known archaeological sites within the probable homeland of the Bantu language group1,2,3,4,5,6,7,8,9,10,11. One individual carried the deeply divergent Y chromosome haplogroup A00, which today is found almost exclusively in the same region12,13. However, the genome-wide ancestry profiles of all four individuals are most similar to those of present-day hunter-gatherers from western Central Africa, which implies that populations in western Cameroon today—as well as speakers of Bantu languages from across the continent—are not descended substantially from the population represented by these four people. We infer an Africa-wide phylogeny that features widespread admixture and three prominent radiations, including one that gave rise to at least four major lineages deep in the history of modern humans.

 

[lpetrich]

Widespread Denisovan ancestry in Island Southeast Asia but no evidence of substantial super-archaic hominin admixture | Nature Ecology & Evolution

Like erectus-like species: Homo luzonensis and H. floresiensis

Ancient genomes from the last three millennia support multiple human dispersals into Wallacea | Nature Ecology & Evolution
Wallacea: islands in present-day Eastern Indonesia and Timor-Leste that were never part of the Sunda or Sahul continental shelves
Sunda: connected to Eurasia
Sahul: connected to Australia

The population history of northeastern Siberia since the Pleistocene | Nature

Northeastern Siberia has been inhabited by humans for more than 40,000 years but its deep population history remains poorly understood. Here we investigate the late Pleistocene population history of northeastern Siberia through analyses of 34 newly recovered ancient genomes that date to between 31,000 and 600 years ago. We document complex population dynamics during this period, including at least three major migration events: an initial peopling by a previously unknown Palaeolithic population of ‘Ancient North Siberians’ who are distantly related to early West Eurasian hunter-gatherers; the arrival of East Asian-related peoples, which gave rise to ‘Ancient Palaeo-Siberians’ who are closely related to contemporary communities from far-northeastern Siberia (such as the Koryaks), as well as Native Americans; and a Holocene migration of other East Asian-related peoples, who we name ‘Neo-Siberians’, and from whom many contemporary Siberians are descended. Each of these population expansions largely replaced the earlier inhabitants, and ultimately generated the mosaic genetic make-up of contemporary peoples who inhabit a vast area across northern Eurasia and the Americas.

Ancient Jomon genome sequence analysis sheds light on migration patterns of early East Asian populations | Communications Biology

Here, we test the deep divergence of the Jomon lineage and the impacts of southern- versus northern-route ancestry on the genetic makeup of the Jomon. The Jomon forms a lineage basal to both ancient and present-day East Asians; this deep origin supports the hypothesis that the Jomon were direct descendants of the Upper Paleolithic people. Furthermore, the Jomon has strong genetic affinities with the indigenous Taiwan aborigines. Our study shows that the Jomon-related ancestry is one of the earliest-wave migrants who might have taken a coastal route on the way from Southeast Asia toward East Asia.

26 kya: East Asians, 23 kya: (Northeast Asians - East Siberians, Native Americans)

Genomic insights into the formation of human populations in East Asia | Nature
Rather complicated

 

[lpetrich]

Peopling of the Americas as inferred from ancient genomics | Nature

In less than a decade, analyses of ancient genomes have transformed our understanding of the Indigenous peopling and population history of the Americas. These studies have shown that this history, which began in the late Pleistocene epoch and continued episodically into the Holocene epoch, was far more complex than previously thought. It is now evident that the initial dispersal involved the movement from northeast Asia of distinct and previously unknown populations, including some for whom there are no currently known descendants. The first peoples, once south of the continental ice sheets, spread widely, expanded rapidly and branched into multiple populations. Their descendants—over the next fifteen millennia—experienced varying degrees of isolation, admixture, continuity and replacement, and their genomes help to illuminate the relationships among major subgroups of Native American populations. Notably, all ancient individuals in the Americas, save for later-arriving Arctic peoples, are more closely related to contemporary Indigenous American individuals than to any other population elsewhere, which challenges the claim—which is based on anatomical evidence—that there was an early, non-Native American population in the Americas. Here we review the patterns revealed by ancient genomics that help to shed light on the past peoples who created the archaeological landscape, and together lead to deeper insights into the population and cultural history of the Americas.

The genomic landscape of Mexican Indigenous populations brings insights into the peopling of the Americas | Nature Communications
"We find evidence that Aridoamerican and Mesoamerican populations diverged roughly 4–9.9 ka, around the time when sedentary farming started in Mesoamerica."

 

[lpetrich]

Ancient Fennoscandian genomes reveal origin and spread of Siberian ancestry in Europe | Nature Communications
 Fennoscandia - Scandinavia, Finland, the Kola Peninsula, and Karelia

European population history has been shaped by migrations of people, and their subsequent admixture. Recently, ancient DNA has brought new insights into European migration events linked to the advent of agriculture, and possibly to the spread of Indo-European languages. However, little is known about the ancient population history of north-eastern Europe, in particular about populations speaking Uralic languages, such as Finns and Saami. Here we analyse ancient genomic data from 11 individuals from Finland and north-western Russia. We show that the genetic makeup of northern Europe was shaped by migrations from Siberia that began at least 3500 years ago. This Siberian ancestry was subsequently admixed into many modern populations in the region, particularly into populations speaking Uralic languages today. Additionally, we show that ancestors of modern Saami inhabited a larger territory during the Iron Age, which adds to the historical and linguistic information about the population history of Finland.

Some of these people likely brought Uralic languages between them -- the Uralic family is recognizable enough to indicate that its breakup was mid-Holocene, like the breakup of Indo-European.

Palaeogenomics of Upper Palaeolithic to Neolithic European hunter-gatherers | Nature

Modern humans have populated Europe for more than 45,000 years1,2. Our knowledge of the genetic relatedness and structure of ancient hunter-gatherers is however limited, owing to the scarceness and poor molecular preservation of human remains from that period3. Here we analyse 356 ancient hunter-gatherer genomes, including new genomic data for 116 individuals from 14 countries in western and central Eurasia, spanning between 35,000 and 5,000 years ago. We identify a genetic ancestry profile in individuals associated with Upper Palaeolithic Gravettian assemblages from western Europe that is distinct from contemporaneous groups related to this archaeological culture in central and southern Europe4, but resembles that of preceding individuals associated with the Aurignacian culture. This ancestry profile survived during the Last Glacial Maximum (25,000 to 19,000 years ago) in human populations from southwestern Europe associated with the Solutrean culture, and with the following Magdalenian culture that re-expanded northeastward after the Last Glacial Maximum. Conversely, we reveal a genetic turnover in southern Europe suggesting a local replacement of human groups around the time of the Last Glacial Maximum, accompanied by a north-to-south dispersal of populations associated with the Epigravettian culture. From at least 14,000 years ago, an ancestry related to this culture spread from the south across the rest of Europe, largely replacing the Magdalenian-associated gene pool. After a period of limited admixture that spanned the beginning of the Mesolithic, we find genetic interactions between western and eastern European hunter-gatherers, who were also characterized by marked differences in phenotypically relevant variants.

 

[lpetrich]

Genomes from Verteba cave suggest diversity within the Trypillians in Ukraine | Scientific Reports

Results reveal that the CTCC individuals’ ancestry is related to both western hunter-gatherers and Near Eastern farmers, has no local ancestry associated with Ukrainian Neolithic hunter-gatherers and has steppe ancestry. An Early Bronze Age individual has an ancestry profile related to the Yamnaya expansions but with 20% of ancestry related to the other Trypillian individuals, which suggests admixture between the Trypillians and the incoming populations carrying steppe-related ancestry. A Late Bronze Age individual dated to 980–825 cal BCE has a genetic profile indicating affinity to Beaker-related populations, detected close to 1000 years after the end of the Bell Beaker phenomenon during the third millennium BCE.

CTCC = Cucuteni-Trypillia cultural complex ~ 5000 - 3000 BCE

Ancestral mitochondrial N lineage from the Neolithic ‘green’ Sahara | Scientific Reports
N is a Western Eurasian one.

Ancient DNA reveals admixture history and endogamy in the prehistoric Aegean | Nature Ecology & Evolution

The Neolithic and Bronze Ages were highly transformative periods for the genetic history of Europe but for the Aegean—a region fundamental to Europe’s prehistory—the biological dimensions of cultural transitions have been elucidated only to a limited extent so far. We have analysed newly generated genome-wide data from 102 ancient individuals from Crete, the Greek mainland and the Aegean Islands, spanning from the Neolithic to the Iron Age. We found that the early farmers from Crete shared the same ancestry as other contemporaneous Neolithic Aegeans. In contrast, the end of the Neolithic period and the following Early Bronze Age were marked by ‘eastern’ gene flow, which was predominantly of Anatolian origin in Crete. Confirming previous findings for additional Central/Eastern European ancestry in the Greek mainland by the Middle Bronze Age, we additionally show that such genetic signatures appeared in Crete gradually from the seventeenth to twelfth centuries bc, a period when the influence of the mainland over the island intensified. Biological and cultural connectedness within the Aegean is also supported by the finding of consanguineous endogamy practiced at high frequencies, unprecedented in the global ancient DNA record. Our results highlight the potential of archaeogenomic approaches in the Aegean for unravelling the interplay of genetic admixture, marital and other cultural practices.

Neolithic end - Early Bronze Age: about 3000 BCE, the beginning of the Minoan civilization.

In 17th - 12th cys. BCE, Greeks arrived from mainland Greece and founded the Cretan branch of the Mycenean civilization, complete with writing in Greek with Linear B. Greek-language speakers had traveled to there from Central/Eastern Europe around 2000 BCE.

 

[lpetrich]

The spread of steppe and Iranian-related ancestry in the islands of the western Mediterranean | Nature Ecology & Evolution

Steppe-pastoralist-related ancestry reached Central Europe by at least 2500 bc, whereas Iranian farmer-related ancestry was present in Aegean Europe by at least 1900 bc. However, the spread of these ancestries into the western Mediterranean, where they have contributed to many populations that live today, remains poorly understood. Here, we generated genome-wide ancient-DNA data from the Balearic Islands, Sicily and Sardinia, increasing the number of individuals with reported data from 5 to 66. The oldest individual from the Balearic Islands (~2400 bc) carried ancestry from steppe pastoralists that probably derived from west-to-east migration from Iberia, although two later Balearic individuals had less ancestry from steppe pastoralists. In Sicily, steppe pastoralist ancestry arrived by ~2200 bc, in part from Iberia; Iranian-related ancestry arrived by the mid-second millennium bc, contemporary to its previously documented spread to the Aegean; and there was large-scale population replacement after the Bronze Age. In Sardinia, nearly all ancestry derived from the island’s early farmers until the first millennium bc, with the exception of an outlier from the third millennium bc, who had primarily North African ancestry and who—along with an approximately contemporary Iberian—documents widespread Africa-to-Europe gene flow in the Chalcolithic. Major immigration into Sardinia began in the first millennium bc and, at present, no more than 56–62% of Sardinian ancestry is from its first farmers. This value is lower than previous estimates, highlighting that Sardinia, similar to every other region in Europe, has been a stage for major movement and mixtures of people.

Evidence of the arrival of speakers of early Indo-European dialects.

The genetic history of admixture across inner Eurasia | Nature Ecology & Evolution
Very complicated.

West Asian sources of the Eurasian component in Ethiopians: a reassessment | Scientific Reports

Our results unveil a genomic legacy that may connect the Eurasian genetic component of contemporary Ethiopians with Sea People and with population movements that affected the Mediterranean area and the Levant after the fall of the Minoan civilization.

Eurasians who likely brought with them Semitic languages -- one branch of that family is the Ethiosemitic branch: Amharic, etc.

 

[lpetrich]

 Mitochondrial Eve

In human genetics, the Mitochondrial Eve (also mt-Eve, mt-MRCA) is the matrilineal most recent common ancestor (MRCA) of all living humans. In other words, she is defined as the most recent woman from whom all living humans descend in an unbroken line purely through their mothers and through the mothers of those mothers, back until all lines converge on one woman.

A woman with at least two daughters who then became the mitochondrial ancestors of all present-day human beings, divided among those daughters.

Having at least two daughters is necessary for having the earliest branching.

She lived around 150,000 - 230,000 years ago (150 - 230 kya), in sub-Saharan Africa, likely in East Africa.

Her mitochondria had  Macro-haplogroup L (mtDNA) with branches L0 to L7 in sub-Saharan Africa. Of these branches,  Haplogroup L3 (mtDNA) is the one which departed from Africa. Its immediate descendants are Haplogroups M and N, and those had other descendant haplogroups.

The L3 people then spread outward in the  Southern Dispersal, in the Arabian Peninsula, Iran, the Indian subcontinent, Southeast Asia, and Oceania, around 70 - 50 kya. They had two offshoot haplogroups, M and N, and these ones in turn had more.  Recent African origin of modern humans

There was also a  Y-chromosomal Adam a man with at least two sons who then became the ancestor of all present-day men and boys, though divided between those sons. He lived about 160 - 300 kya, and his Y chromosomes had  Haplogroup A (Y-DNA)

MItochondrial Eve and Y-chromosome Adam are also called the mt-MRCA and Y-MRCA, "most recent common ancestor".

Modern humanity's ancestors split from the ancestors of the Neanderthals and Denisovans about 760 - 550 kya (full genome), 806 - 447 kya (Y chromosome), but Neanderthal - modern-human 498 - 295 kya (mitochondria), an odd discrepancy. Some interbreeding somewhere?

 

[lpetrich]

 Toba catastrophe theory

The Toba eruption, (sometimes called the Toba supereruption or the Youngest Toba eruption) was a supervolcano eruption that occurred around 74,000 years ago[1] at the site of present-day Lake Toba in Sumatra, Indonesia. It is one of the Earth's largest known explosive eruptions. The Toba catastrophe theory holds that this event caused a severe global volcanic winter of six to ten years and contributed to a 1,000-year-long cooling episode, leading to a genetic bottleneck in humans.[2][3]

A number of genetic studies revealed that 50,000 years ago human ancestor population greatly expanded from only a few thousand individuals.[4][5] Science journalist Ann Gibbons posited that the low population size was caused by the Toba eruption.[6] Geologist Michael R. Rampino of New York University and volcanologist Stephen Self of the University of Hawaiʻi at Mānoa supported her suggestion.[7] In 1998, the bottleneck theory was further developed by anthropologist Stanley H. Ambrose of the University of Illinois Urbana-Champaign.[2] However, some physical evidence disputes the links with millennium-long cold event and genetic bottleneck, and some consider the theory disproven.[8][9][10][11][12]

Some other species had genetic bottlenecks around then.

Some evidence points to genetic bottlenecks in other animals in the wake of the Toba eruption. The populations of the Eastern African chimpanzee,[60] Bornean orangutan,[61] central Indian macaque,[62] cheetah and tiger,[63] all recovered from very small populations around 70,000–55,000 years ago.

This was around present-day humanity's first departure from Africa, maybe a little before, maybe a little after. If after, was there some connection?

 

[lpetrich]

 Early expansions of hominins out of Africa and  Recent African origin of modern humans and  Early human migrations

The first of them left evidence:  Oldowan tools, from 2.9 Mya to 1.7 Mya in eastern and southern Africa, and in the southern half of Eurasia. These were stones with one or two pieces knocked off by smashing other stones into them ("knapping"), with those flakes being the desired parts.

It is not known for sure which hominin species created and used Oldowan tools. Its emergence is often associated with the species Australopithecus garhi[8] and its flourishing with early species of Homo such as H. habilis and H. ergaster. Early Homo erectus appears to inherit Oldowan technology and refines it into the Acheulean industry beginning 1.7 million years ago.[9]

Next was  Acheulean from 1.76 Mya to 130 kya, with a similar distribution, with W and NW Africa and NW Europe added. These "hand axes" were made with several smashes, to make tools that were sometimes flattened.

Most notably, however, it is Homo ergaster (sometimes called early Homo erectus), whose assemblages are almost exclusively Acheulean, who used the technique. Later, the related species Homo heidelbergensis (the common ancestor of both Neanderthals and Homo sapiens) used it extensively.[citation needed] Late Acheulean tools were still used by species derived from H. erectus, including Homo sapiens idaltu and early Neanderthals.[36]

 Mousterian from 160 to 40 kya, and including earlier  Levallois technique finds, it goes back as far as 300 - 200 kya. Its main user was Neandethals.

 Aurignacian from 43 kya to 28 kya, by modern humans in Europe, followed by  Gravettian from 33 kya to 21 kya, then by  Solutrean from 22 kya to 17 kya in W and SW Europe, then by  Magdalenian from 17 kya to 12 kya, also in W and SW Europe.

Even in the Paleolithic, our species was more innovative than earlier species, it seems.

 

[lpetrich]

The ancestors of ex-African human populations first left Africa around 70 - 50 kya. and then spread over Southwest, South, and Southeast Asia. But when they did, Neanderthals inhabited Eurasia from Europe to Central Asia, and Denisovans from there to Eastern Asia. The first present-day humans to arrive in Europe arrived around 45 - 43 kya, and the Neanderthals went extinct around 41 - 39 kya.  Neanderthal extinction mentions numerous hypotheses, hypotheses that are not necessarily exclusive.

The  Campanian Ignimbrite eruption around 40 - 39 kya may have combined with competitive exclusion to finish off the Neanderthals.