Tag Archives: Asia

Macrohaplogroup M in Asia, one clade estmated at over 84,000 years old.

This MtDNA Macrohaplogroup was recently nailed down to an Asian origin.

In situ origin of deep rooting lineages of mitochondrial Macrohaplogroup ‘M’ in India
Kumarasamy Thangaraj* 1 , Gyaneshwer Chaubey* 1,2 , Vijay Kumar Singh1 , Ayyasamy Vanniarajan1 , Ismail Thanseem1 , Alla G Reddy1  and Lalji Singh1

© 2006 Thangaraj et al; licensee BioMed Central Ltd.

Macrohaplogroups ‘M’ and ‘N’ have evolved almost in parallel from a founder haplogroup L3. Macrohaplogroup N in India has already been defined in previous studies and recently the macrohaplogroup M among the Indian populations has been characterized. In this study, we attempted to reconstruct and re-evaluate the phylogeny of Macrohaplogroup M, which harbors more than 60% of the Indian mtDNA lineage, and to shed light on the origin of its deep rooting haplogroups.

Results
Using 11 whole mtDNA and 2231 partial coding sequence of Indian M lineage selected from 8670 HVS1 sequences across India, we have reconstructed the tree including Andamanese-specific lineage M31 and calculated the time depth of all the nodes. We defined one novel haplogroup M41, and revised the classification of haplogroups M3, M18, and M31.

Conclusion
Our result indicates that the Indian mtDNA pool consists of several deep rooting lineages of macrohaplogroup ‘M’ suggesting in-situ origin of these haplogroups in South Asia, most likely in the India. These deep rooting lineages are not language specific and spread over all the language groups in India. Moreover, our reanalysis of the Andamanese-specific lineage M31 suggests population specific two clear-cut subclades (M31a1 and M31a2). Onge and Jarwa share M31a1 branch while M31a2 clade is present in only Great Andamanese individuals. Overall our study supported the one wave, rapid dispersal theory of modern humans along the Asian coast

The dazzling array of basal branches in the mtDNA macrohaplogroup M from India as inferred from complete genomes.

Sun C, Kong QP, Palanichamy MG, Agrawal S, Bandelt HJ, Yao YG, Khan F, Zhu CL, Chaudhuri TK, Zhang YP.
Laboratory of Cellular and Molecular Evolution, and Molecular Biology of Domestic Animals, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.

Many efforts based on complete mitochondrial DNA (mtDNA) genomes have been made to depict the global mtDNA landscape, but the phylogeny of Indian macrohaplogroup M has not yet been resolved in detail. To fill this lacuna, we took the same strategy as in our recent analysis of Indian mtDNA macrohaplogroup N and selected 56 mtDNAs from over 1,200 samples across India for complete sequencing, with the intention to cover all Indian autochthonous M lineages. As a result, the phylogenetic status of previously identified haplogroups based on control-region and/or partial coding-region information, such as M2, M3, M4, M5, M6, M30, and M33, was solidified or redefined here. Moreover, seven novel basal M haplogroups (viz., M34-M40) were identified, and yet another five singular branches of the M phylogeny were discovered in the present study. The comparison of matrilineal components among India, East Asia, Southeast Asia, and Oceania at the deepest level yielded a star-like and nonoverlapping pattern, reflecting a rapid mode of modern human dispersal along the Asian coast after the initial “out-of-Africa” event.

Ancient mitochondrial M haplogroups identified in the Southwest Pacific
D. Andrew Merriwether†,‡, Jason A. Hodgson†, Françoise R. Friedlaender§, Robin Allaby†, Salvatore Cerchio†, George Koki¶, and Jonathan S. Friedlaender§
(received for review June 6, 2005)

Abstract
Based on whole mtDNA sequencing of 14 samples from Northern Island Melanesia, we characterize three formerly unresolved branches of macrohaplogroup M that we call haplogroups M27, M28, and M29. Our 1,399 mtDNA control region sequences and a literature search indicate these haplogroups have extremely limited geographical distributions. Their coding region variation suggests diversification times older than the estimated date for the initial settlement of Northern Island Melanesia. This finding indicates that they were among the earliest mtDNA variants to appear in these islands or in the ancient continent of Sahul. These haplogroups from Northern Island Melanesia extend the existing schema for macrohaplogroup M, with many independent branches distributed across Asia, East Africa, Australia, and Near Oceania

This gives the founder dates for one of these M (M27) variants as ~84,000 years old. Which asks the question how can the MRCA of all M be less than about 90,000 years plus-suggesting that the current est. date for M in South Asia at about 74,000 might be a wee bit too young. This would push the exit date from Africa back quite a long way, if it’s accurate.

The overall (average) age of M had been estimated with the Saillard and Mishmar approach at 64,800 years with a standard error of 7,100 years, taken to conform to proposed dates for a “Southern Route” expansion between 55,000 and 85,000 YBP (39). With our data, the combined estimate for Near Oceanic Ms becomes 72,100 ± 8,000, with the estimate for the M27 branch, taken alone, as 84,400 ± 14,300 years (Table 3). Our calculation for the Australian Aboriginal M42 haplogroup age estimate is in the same range. Link

 

Paleolithic Europe populated from Asia

First Europeans Came From Asia, Not Africa, Tooth Study Suggests
Kate Ravilious
for National Geographic News
August 6, 2007
Europe’s first early human colonizers were from Asia, not Africa, a new analysis of more than 5,000 ancient teeth suggests.
Researchers had traditionally assumed that Europe was settled in waves starting around two million years ago, as our ancient ancestors—collectively known as hominids—came over from Africa.
But the shapes of teeth from a number of hominid species suggest that arrivals from Asia played a greater role in colonizing Europe than hominids direct from Africa.
These Asian hominids may have originally come from Africa, the scientists note, but had evolved independently for some time.
“Asia was also an important center for hominid speciation,” said Maria Martinón-Torres, a scientist at the National Research Center on Human Evolution in Burgos, Spain, who led the study.
The finding suggests that the hominid family tree could be much more complex than previously thought (explore an interactive atlas of human migration).
Species from the genus Australopithecus and the genus Homo arrived in Europe between two million and 300,000 years ago.
Until recently, a lack of fossils from this time period had made it difficult to piece together hominid evolution and migration patterns.
But using the latest fossil findings, Martinón-Torres and colleagues were able to examine more than 5,000 teeth from two-million-year-old Australopithecus and Homo skeletons from Africa, Asia, and Europe.
The shape of the teeth offered clues about each species’ genetic lineages.
“Teeth are like the safe-box of the genetic code,” Martinón-Torres said.
That’s because—compared to bones—teeth change shape very little once they are formed, and their shape is strongly influenced by genetics.
The researchers classified each of the teeth using more than 50 indicators, such as fissure patterns, overall size, and length-to-width ratio.
“We looked at the entire landscape of the teeth—the mountains, valleys, ridges—everything,” Martinón-Torres said.
What they found is that European teeth were more similar to Asian teeth than they were to African teeth.
However, the results don’t rule out African influence on European genes.
“This finding does not necessarily imply that there was not genetic flow between continents,” Martinón-Torres and colleagues write in their paper, “but emphasizes that this interchange could have been both ways.”
The work will be published in tomorrow’s issue of the Proceedings of the National Academy of Sciences.
Fluid Migrations
Rather than a one-way stream of people coming from Africa, Martinón-Torres and colleagues think there must have been a more fluid pattern of migrations.
“Just because people had come out of Africa didn’t mean that they couldn’t turn around and go back again,” she said.
The researcher also believes that climate, food, and geography were major influences on hominid migration patterns.
The Sahara, for example, presented a big barrier for movement out of Africa and directly into Europe (see photos and read a related feature about athletes who ran across the Sahara earlier this year).
Rather than struggling across the Sahara, it appears that human ancestors spread in many directions before arriving in Europe.
Erika Hagelberg, a geneticist from the University of Oslo in Norway, is impressed with the study, but cautious about how it should be interpreted.
“The study shows that the genetic impact of Asia on Europe is stronger than that of Africa. But the teeth can’t tell us the direction or the time when people migrated,” she said.
Nonetheless, the new study does complement direct gene studies and supports the idea that hominids evolved independently in many different parts of the world.
“The fossil teeth are a way to study the traits of past peoples,” Hagelberg said, “and help balance the work being done on the genes of people alive today.”

Well, duh, we knew that from the fossils. Nice to have corroborating evidence though.

People in Asia before Toba?

by Stephen Oppenheimer,

Borrowed from The Bradshaw foundation, a site well worth several visits.
Dating the arrival of Anatomically Modern Humans in East Asia: Who made the Kota Tampan tools and when?



No one has done more research into Kota Tampan and the Lenggong Valley culture than archaeologist Zuraina Majid, of the Universiti Sains Malaysia in Penang. Her extensive work at a number of sites in the Lenggong Valley suggests that a local pebble-tool culture may have existed from the days of that great Toba volcanic eruption right up until 7,000 or even only 4,000 years ago. If that is so, it may provide the answer to one of the most nagging questions about the unifacial oval pebble tools: who made them? On the face of it, these are by no stretch of the imagination sophisticated tools. Better-looking tools were made long before in Africa and Europe by archaic humans, so why should anyone think that the unifacial pebbles encased in volcanic ash had been made by modern humans living at the time of Toba?
 
Two of the highest authorities on the Southeast Asian Palaeolithic, Australian archaeologists Peter Bellwood and Sandra Bowdler, agree with Zuraina Majid and Tom Harrison to the extent that these tools were most likely made by Anatomically Modern Humans. For a start, the dates for most of the pebble tools found in the Lenggong Valley are too recent for them to have been made by anyone else. Second, no pre-modern humans have ever been found in the Malay Peninsula, let alone in the Lenggong Valley.  

Perak Man

Zuraina’s trump card in this respect is the much publicized finding by her team of ‘Perak Man’ in the Gunung Runtuh cave in the Lenggong Valley in 1990. Surrounded by the same class of pebble tools, this complete skeleton of a modern human was described by experts as having Australo-Melanesian characteristics. He was about 10,000 years old. This clear recent association of pebble tools with modern humans undermines the argument that the Kota Tampan pebble tools were too crude to be the work of moderns. The same locality also provides a continuity link with the older tools, which Zuraina argues is supported by technical comparisons. So, for the moment at least, Perak Man is the best local evidence that the older pebble tools encased in ash were made by the same (modern) human species.
 
Another venerable expert on the archaeology of Southeast Asia is Richard Shutler. He makes the more general point that these kinds of tools were first brought to Island Southeast Asia (meaning all the islands of Indonesia, Malaysia and the Philippines) by Homo sapiens about 70,000 years ago. Shutler cautions against the view that such tools reflect cultural backwardness, agreeing with others that the quality of the available raw material determined what could be used for tools, and that for more sophisticated implements such as knives, bamboo was more likely to have been used.
 

So how old was the Kota Tampan ash?

When it was first dated, several decades ago, the result came out at 31,000 years old. This date for ash from the Toba volcano has always worried geologists, and even archaeologists such as Peter Bellwood. The trouble is that Toba did not undergo a massive explosion at that time. Toba’s last big bang, the largest explosion in the world in the past 2 million years, came much earlier, 71,000–74,000 years ago. More recently several geologists, including the one who did the original dating, have agreed that the ash surrounding the tools was indeed 74,000 years old. The dating is critical. If the Kota Tampan pebble tools were made by modern humans, they would be the oldest precisely dated evidence for modern humans outside Africa. It therefore looks as though the ancestors of the Australians could well have left Africa and arrived in Malaysia on their beachcombing trail before the great Toba explosion.
 

Liujiang Skull


Another piece of evidence from the region may help place Anatomically Modern Humans in the Far East over 70,000 years ago. This is the famous southern Chinese Liujiang skeleton. Consisting of a well-preserved skull and a few other bones, Liujiang was discovered in a small cave at Tongtianyan in the Guangxi Zhuang Autonomous Region in 1958 by people collecting fertilizer. There is no doubt that this person was anatomically modern, but from the start there has been controversy over its age.

 

A uranium date of 67,000 years was reported, but has been questioned on the basis of its exact location in relation to dated geological strata. In December 2002, a Chinese group headed by geologist Shen Guanjun reported their reinvestigation of the stratigraphy of the cave and dating of the skull (extending to several neighbouring caves) and claim it should be placed in a time bracket between 70,000 and 130,000, and not less than 68,000, years ago. The skull was found in a so-called intrusive breccia, a secondary flow of debris containing jumbled material of different ages. From their paper in the prestigious Journal of Human Evolution, the lower date bracket of 68,000 years seems solid, since it comes from multiple date estimates of the flowstone above and covering the breccia. (A flowstone forms when flowing water deposits calcite down a wall or across a floor.) Their preferred dating of 111,000–139,000 years ago based on unstratified fragments of flowstone and calcite within the breccia seems more speculative.
 
I have stuck my neck out to place modern humans in Malaysia by this date on the basis of the Kota Tampan site where tools were found under a thick layer of volcanic ash from Toba. The key tools were indisputably artefacts, and the ash did come straight from the sky 74,000 years ago. But in spite of majority view that the Kota Tampan tools were the handiwork of modern humans, they could still theoretically have been made by other humans, since no bones have been found on-site which would confirm the identity of their makers. The only modern human remains of that antiquity found in the region are the now re-dated Liujiang skull and partial skeleton from southern China. The dating of the earliest Flores (Eastern Indonesia) occupation by modern humans remains to be published. I have several corroborating reasons for relying on such a connection. First of all, the logic of the low-water colonization of Australia 65,000 years ago fits; and second, increasing numbers of genetic dates outside Africa easily reach back to this time. The next available low-water slot for the colonization of Australia would have been around 50,000 years ago, but that does not fit the other evidence so well.

The mount Toba event

Borrowed from the Bradshaw Foundation
by Stephen Oppenheimer

The Toba explosion 74,000 years ago and the genetic evidence.
 
Perhaps more important than the precision of the dating, the connection between stone tools and Toba volcanic ash in Malaysia puts the first Indians and Pakistanis in the direct path of the greatest natural calamity to befall any humans, ever. The Toba explosion was that disaster, the biggest bang in 2 million years. Carried by the wind, the plume of ash from the volcano fanned out to the north-west and covered the whole of the Indian subcontinent. Even today, a metres-thick ash layer is found throughout the region, and is associated in two Indian locations with Middle and Upper Palaeolithic tools. An important prediction of this conjunction of tools and ash is that a deep and wide genetically sterile furrow would have split East from West; India would eventually recover by re-colonisation from either side. Such a furrow does exist in the genetic map of Asia.
 
In spite of the proximity of Toba to Perak, the Toba ash plume only grazed the Malay Peninsula. The human occupants of the Kota Tampan site were the unlucky ones – others on the peninsula escaped. Some argue, on the basis of comparing skull morphologies, that the Semang aboriginal ‘Negrito’ hunter-gatherers, who still live in the same part of the dense northern Malaysian rainforest, are descendants of people like Perak Man. The continuity of the Kota Tampan culture as argued by Zuraina Majid provides a link back to the 74,000-year-old tools in the Toba ash.
The Semang are perhaps the best known of the candidate remnants of the old beachcombers. Another relict group possibly left over from the beachcombers in Indo-China and the Malay Peninsula are the so-called Aboriginal Malays, who are physically intermediate between the Semang and Mongoloid populations.
 
For a film documentary, The Real Eve (Out of Eden in the UK), with with which Stephen Oppenheimer ‘s book is associated, Discovery Channel helped to fund a genetic survey of the aboriginal groups of the Malay Peninsula which I conducted in collaboration with English geneticist Martin Richards and some Malaysian scientists. This survey was part of a much larger on-going study of East Asian genetics.
 
The mtDNA results were very exciting: three-quarters of the Semang group (i.e. the ‘Negrito’ types) have their own unique genetic M and N lines with very little admixture from elsewhere, which is consistent with the view that their ancestors may have arrived with the first beachcombers. Their two unique lines trace straight back to the M and N roots (the first two daughters of L3 outside Africa). Their M line is not shared with anyone else in Southeast Asia or East Asia (or anywhere else) and, although it has suffered loss of diversity through recent population decline, it retains sufficient diversity to indicate an approximate age of 60,000 years. Their other unique group on the N side comes from R, N’s genetic daughter. This lack of any specific connection with any other Eurasian population is consistent with the idea that after arriving here so long ago, they have remained genetically isolated in the jungles of the Malay Peninsula.
 

The colonisation of Australia over 60,000 years ago was part of the same Exodus

Some are still convinced that Australian aboriginals represent an earlier migration out of Africa than that which gave rise to Europeans, Asians, and Native Americans. Yet again our genetic trail tells us otherwise. Several studies of Australian maternal clans have shown that they all belong to our two unique non-African superclans, M and N, and large studies of Y chromosomes show that male Australian lines all belong to the same Out-of-Africa Adam clan as other non-Africans (M168). The same pattern is seen with genetic markers not exclusively transmitted through one parent. In other words, the combined genetic evidence strongly suggests Australians are also descendants of that same single out-of-Africa migration. The logic of this approach, combined with the archaeological dates, places the modern human arrival in the Malay Peninsula before 74,000 years ago and Australia around 65,000 years ago. It is also consistent with the date of exit from Africa predicted on beachcombing grounds.
 
My date estimates for the trek around the Indian Ocean en route from Africa suggest that the beachcombers could have taken as little as 10,000 years to eat their way down the coastline to Perak and roughly another 10,000 years to reach Australia. Such a time requirement is fulfilled by the difference between leaving Africa around 85,000 years ago and arriving in Australia 65,000 years ago. The former date is consistent with dates estimated for the African L3 cluster expansion using the molecular clock.
 

A genetic furrow in India resulting from the Toba explosion?

There is an abrupt genetic change to the north and east of India. These changes can be inferred even from physical appearance. In Nepal, Burma, and eastern India we come across the first Mongoloid East Asian faces. These populations generally speak East Asian languages, contrasting strongly with their neighbours who mostly speak Indo-Aryan or Dravidian languages. By the time we get to the east of Burma and to Tibet on the northern side of the Himalayas, the transition to East Asian appearance and ethnolinguistic traditions is complete, as is the rapid and complete change of the mitochondrial sub-clans of M and N. In Tibet, for instance, the ratio of M to N clans has changed from 1:5 to 3:1, and there is no convincing overlap of their sub-clans with India. Instead, Tibet shows 70 per cent of typical East and Southeast Asian M and N sub-clans, with the remainder consisting of as-yet unclassified M types of local origin. The north-eastern part of the Indian subcontinent therefore shows the clearest and deepest east–west boundary. This boundary possibly reflects the deep genetic furrow scored through India by the ash-cloud of the Toba volcano 74,000 years ago.
 
To the south of the Indian peninsula, the main physical type generally changes towards darker-skinned, curly haired, round-eyed so-called Dravidian peoples. Comparisons of skull shape link the large Tamil population of South India with the Senoi, a Malay Peninsular aboriginal group intermediate between the Semang and Aboriginal Malays (see above).
 

M born in India, N possibly a little farther west in the Gulf.

M, who is nearly completely absent from West Eurasia, gives us many reasons to suspect that her birthplace is in India. M achieves her greatest diversity and antiquity in India. Nowhere elsem does she show such variety and such a high proportion of root and unique primary branch types. The eldest of her many daughters in India, M2, even dates to 73,000 years ago. Although the date for the M2 expansion is not precise, it might reflect a local recovery of the population after the extinction that followed the eruption of Toba 74,000 years ago. M2 is strongly represented in the Chenchu hunter-gatherer Australoid tribal populations of Andhra Pradesh, who have their own unique local M2 variants as well as having common ancestors with M2 types found in the rest of India. Overall, these are strong reasons for placing M’s birth in India rather than further west or even in Africa.
 
What is perhaps most interesting about the unique Indian flowerings of the M and R clans is a hint that they represent a local recovery from the Toba disaster which occurred 74,000 years ago, after the out-of-Africa trail began. A devastated India could have been re-colonised from the west by R types and from the east more by M types. Possible support for this picture comes from the recent study by Kivisild and colleagues of two tribal populations in the south-eastern state of Andhra Pradesh. One of these populations, the Australoid Chenchu hunter-gatherers, are almost entirely of the M clan and hold most of the major M branches characteristic of and unique to India. The other group, the non-Australoid Koyas, have a similarly rich assortment of Indian type M branches (60 per cent of all lines), but have 31 per cent uniquely Indian R types. The Chenchu and Koya tribal groups thus hold an ancient library of Indian M and R genetic lines which are ancestral to, and include, much of the maternal genetic diversity that is present in the rest of the Indian subcontinent. Neither of these two groups holds any West Eurasian N types. The presence of R types in the Koyas but not in the Australoid Chenchus might fit with some component of a recolonization from the Western side of the Indian subcontinent. As evidence of their ancient and independent development, and in spite of their clearly Indian genetic roots and locality, there were no shared maternal genetic types (i.e. no exact matches) between the two tribal groups.

laketoba.jpg

The resulting lake left by the Mount Toba eruption.

The blue dots show the deposition of ash from the eruption. The red line marks the likely zone inside which no-one survived, although this is disputed.
Late Pleistocene human population bottlenecks, volcanic winter, and differentiation of modern humans.

 

Extract from “Journal of Human Evolution”

[1998] 34, 623-651

 

The last glacial period was preceded by 1000 years of the coldest temperatures of the Late Pleistocene, apparently caused by the eruption of the Mount Toba volcano. The six year long volcanic winter and 1000-year-long instant Ice Age that followed Mount Toba’s eruption may have decimated Modern Man’s entire population. Genetic evidence suggests that Human population size fell to about 10,000 adults between 50 and 100 thousand years ago. The survivors from this global catastrophy would have found refuge in isolated tropical pockets, mainly in Equatorial Africa. Populations living in Europe and northern China would have been completely eliminated by the reduction of the summer temperatures by as much as 12 degrees centigrade.Volcanic winter and instant Ice Age may help resolve the central but unstated paradox of the recent African origin of Humankind: if we are all so recently “Out of Africa”, why do we not all look more African?Because the volcanic winter and instant Ice Age would have reduced populations levels low enough for founder effects, genetic drift and local adaptations to produce rapid changes in the surviving populations, causing the peoples of the world to look so different today. In other words, Toba may have caused Modern Races to differentiate abruptly only 70,000 years ago, rather than gradually over one million years.


Volcanic Winter

 

The Mount Toba eruption is dated to approximately 71,000 years ago. Volcanic ash from Mount Toba can be traced north-west across India, where a widespread terrestrial marker bed exists of primary and reworked airfall ash, in beds that are commonly 1 to 3, and occasionally 6 meters [18 feet] thick.Tambora, the largest known historic eruption, displaced 20 cubic kilometres of ash. Mount Toba produced 800 cubic kilometres.* It was therefore forty times larger than the largest eruption of the last two centuries and apparently the second largest known explosive eruption over the last 450 million years.


Volcanic Winter, and Differentiation of Modern Humans

 

Mount Toba’s eruption is marked by a 6 year period during which the largest amount of volcanic sulphur was deposited in the past 110,000 years. This dramatic event was followed by 1000 years of the lowest ice core oxygen isotope ratios of the last glacial period. In other words, for 1000 years immediately following the eruption, the earth witnessed temperatures colder than during the Last Glacial Maximum at 18-21,000 years ago.For the volcanic aerosols to be effectively distributed around the earth, the plume from the volcanic eruptions must reach the stratosphere, a height greater than 17 kilometres. Mount Toba’s plume probably reached twice this height. Most solar energy falls at low latitudes between the Tropics of Cancer and Capricorn, so eruptions that happen near the Equator cause much more substantial cooling due to the reflection of solar energy. Toba lies 2 degrees north of the Equator, on the Island Sumatra.The reduction in atmospheric visibility due to volcanic ash and dust particles is relatively short-lived, about three to six months. Longer-term global climatic cooling is caused by the highly reflective sulphuric acid haze, which stays suspended in the upper atmosphere for several years.Ice core evidence implicates Mount Toba as the cause of coldest millennium of the late Pleistocene. It shows that this eruption injected more sulphur that remained in the atmosphere fo a longer time [six years] than any other volcanic eruption in the last 110,000 years. This may have caused nearly complete deforestation of southeast Asia, and at the same time to have lowered sea surface temperatures by 3 to 3.5 degrees centigrade for several years.If Tambora caused the ” The year without a summer” in 1816, Mount Toba could have been responsible for six years of relentless volcanic winter, thus causing a massive deforestation, a disastrous famine for all living creatures, and a near extinction of Humankind.

The Volcanic Winter/Weak Garden of Eden model proposed in this paper. Population subdivision due to dispersal within African and other continents during the early Late Pleistocene is followed by bottlenecks caused by volcanic winter, resulting from the eruption of Toba, 71 ka. The bottleneck may have lasted either 1000 years, during the hyper-cold stadial period between Dansgaard-Oeschlger events 19 and 20, or 10ka, during oxygen isotope stage 4. Population bottlenecks and releases are both sychronous. More individuals survived in Africa because tropical refugia were largest there, resulting in greater genetic diversity in Africa.
 
 

 

I’ve had a dig about, and there does seem to be a recorded ‘volcanic winter’ in the ice cores from that era. I can’t find any evidence for any mass extinctions from that era, and the Neanderthals seem to have survived it fine. But, having read up on ‘the year without a summer’, this would in my opinion, have caused a major population crash. This was caused by about 150 cubic kilometers of ash being ejected into the atmosphere, the Toba eruption ejected 2800 cubic kilometers. That had to have had a serious effect. 

Although…

 Archaeologists found the stone tools at a site called Jwalapuram, in Andhra Pradesh, southern India, above and below a thick layer of ash from the eruption of the Toba volcano in Indonesia — an event known as the Youngest Toba Tuff eruption.The tools from each layer were remarkably similar, and Petraglia says that this shows that the huge dust clouds from the eruption didn’t wipe out the population of tool-using people. “Whoever was there seems to have persisted through the eruption,” he says.This is the first archaeological evidence associated with the Toba super eruption, says Petraglia, and it contradicts theories that the eruption had a catastrophic effect on the area that its ash blanketed.

The super-eruption of Toba, did it cause a human bottleneck?

F. J. Gathorne-Hardy et al.

In summary, we have not been able to find any evidence to support the hypothesis that the Toba super-eruption of 73.5 Ka caused a bottleneck in the human population. The direct effects of the eruption were fairly localised, and at the time probably had a negligible effect on any human population in Asia, let alone Africa. Genetic evidence indicates that the Pleistocene human population bottleneck was not hour-glass shaped, but rather an up-side down bottle with a long neck. Modern humans at that time were adaptable, mobile, and technologically well-equipped, and it is likely that they could have dealt with the short-term environmental effects of the Toba event. Finally, we have found no evidence for associated animal decline or extinction, even in environmentally-sensitive species. We conclude that it is unlikely that the Toba super-eruption caused a human, animal or plant population bottleneck.