The map of Northern Asia was now starting to fill up. By 30,000 years ago, a large swathe of the wooded southern part of the former Soviet Union, from the Russian Altai through Lake Baikal in southern Siberia to the Aldan River in the east, had been colonized by modern pioneers carrying a technology similar to that of the contemporary European Upper Palaeolithic. Even the Arctic Circle was penetrated north of the Urals nearly 40,000 years ago. There is some evidence that the Upper Palaeolithic technology of North Eurasia may have travelled south to Inner Mongolia on a northern bend of the Yellow River, but on present evidence it seems that at this time such cultural influences spread no farther south into China.
Dale Guthrie's vision of the hunter-gatherers wandering the great Asian Mammoth Steppe, stretching from eastern Siberia right across to Europe, takes shape in the archaeological record of around 30,000 years ago. His prediction of the incipient 'Mongoloid' homeland in the southern Steppe is, however, highly speculative for this period and for Siberia. For a start, as mentioned, no indisputably Mongoloid remains have been found from such an early date. For all we know, those early southern Siberians could have looked like the Cro-Magnons of Europe. They shared a similar culture and, at least according to the story told us by the Y-chromosome lines, they shared genes with North Europeans. As evidence perhaps of a Western cultural centre of gravity, the first flowering of the mammoth culture at this time seems to have taken place much farther west, in Central and Eastern Europe .
WHAT CAUSES THE ICE AGES
Modern views as to the heavenly movements that influence the timing of the waxing and waning of the ice caps and the resulting rise and fall of the oceans, are still influenced by astronomical theories pioneered by the nineteenth-century glaciologists. These theories have been collected in the twentieth century under one name, the 'Milankovitch hypothesis' of ice ages.
The genius of Milankovitch:
Out of place, out of time
Milutin Milankovitch was a Serb. He was caught in the wrong country at the outbreak of the Great War in 1914 and interned. Luckily a friendly Hungarian professor had him paroled and moved from his cell to Budapest where he had access to the library of the Hungarian Academy of Sciences. Oblivious to the war, he continued his calculations and finally published his first set of predictions in 1920. The genius of Milankovitch lay in the correct combination of astronomical cycles and meticulous calculation. When he died in 1958, the theory was falling out of vogue partly because of various discrepancies between his predictions and geologists' findings. Since then, the older techniques of geologists, particularly the accuracy of carbon-dating, have been found wanting and the Milankovitch model has emerged triumphant, thus standing the test of time.
<i>A detailed description of the theory can be found elsewhere (see A.G.Dawson, Ice Age Earth, Routledge, London, 1992, chapter 13). But it is important to realise that frequent, apparently random, episodes of warming and cooling of the Earth can be explained to a great extent by the interplay of at least three celestial cycles, all running at different speeds. These cycles affect the warmth transmitted by the Sun to various parts of the Earth in a complex way. Of particular importance for the onset of glaciation is a decline in heat transmitted to northern temperate latitudes during summer with the resulting failure to melt last winter's snow. The amount of summer sun is controlled by three important heavenly cycles, which can be called respectively: the 100,000-year stretch, the 41,000-year tilt and the 23,000-year wobble.
Every year when the Earth circles the Sun, it moves alternately nearer and farther at different points of the circuit. This motion is called elliptical and the Sun lies to one end of the ellipse rather than in the middle. Over a period of approximately 100,000 years this ellipse stretches somewhat, and then shortens and fattens until it is nearly circular. The process is rather like taking a childâs hula-hoop and distorting it intermittently with two hands to make an ellipse. Over the cycle, the distance between the Earth and the Sun varies by as much as 18.26 million kilometres (11.35 million miles). Although the change in heat delivery over this cycle is relatively small, the effect on the Earth's climate is, for some reason, greater than with the other two mechanisms. At present the Sun's circuit does not particularly favour an ice age, but the onset of the next major glaciation can be predicted accurately from the cycles.
As we know the Earthâs axis of rotation is tilted at an angle to the Sun. The situation is rather like a top that will not spin upright. This is the reason for summer and winter, as the globe presents first its northern then its southern face to the Sun during one circuit. At present the tilt is about 23.5 degrees, but it varies between 21.5 and 24.5 degrees over a cycle of roughly 41,000 years. The greater the tilt, the more the seasonal imbalance in heat delivery from the Sun and the less the chance of ice remaining through the summer in temperate climates. At present we are near a neutral point between the extremes of this oscillation of tilt, thus neither favouring nor promoting an ice age.
The Earth is very like a childâs top in other ways. Not only does it spin at an angle of about 23 degrees to the Sun, but it also performs a slow pirouette as the sloped axis gyrates round itself. If you were a god accompanying the earth on its orbit round the Sun but perched up high looking down on the North Pole from directly above, you would see the pole performing a slow circle every 22,000 to 23,000 years. If you could see right through an imaginary glass globe to the South Pole you would see it performing the same circle 180 degrees out of phase. This spinning of the axis on itself is called axial precession, and all spinning tops can do it.</i>
<b>The effect of this precession is that the Earth slowly changes the face it presents to the Sun at different parts of the elliptical orbit. Precession does not change the angle of tilt, merely the direction of tilt. As a result, in the next 11,000 years or so, 21 June will become mid-winter in Europe and North America, and mid-summer in Australia. A fancy term for this slow ballet is the 'precession of the equinoxes'.</b>
At present, the Earth presents the Northern Hemisphere to the Sun (i.e. during summer) when it is at its furthest away from the Sun. Conversely, the Southern Hemisphere has its summer when it is nearest to the Sun. <b>Todayâs position of axial precession, therefore, actually favours glaciation in the Northern Hemisphere. There was a similar situation about 20,000 years ago at the height of the last great ice age, but then the position of the other two cycles happened to tip the balance towards glaciation. About 11,000 years ago the summers were warmer in the Northern Hemisphere, which should have favoured melting of the polar ice caps.</b>
The Milankovitch cycles are thus three elegant and stately celestial dances completely out of time with each other. They play out infinite yet predictable variations of heat stress on our planetary climate. In the last twenty years geologists and oceanographers have developed methods that enable them to measure indirectly, the past course and variations in the melting and freezing of the ice caps. The more refined these measurements have become, the better they fit Milankovitchâs model predictions of the waxing and waning of the ice ages of the past 2 million years
GENETIC CONTINUITY AND THE LAST GLACIATION
Can the genetic record tell us more about the ebb and flow of populations in the real human sense of where they came from and went to, rather than the inferred cultural picture of what they were doing, as the cold grip of the ice took hold? Genetic tracing can and does fit the archaeological record of that time rather nicely, but it also tells us something much more relevant and general to European roots: that 80 per cent of modern European lines are essentially derived from ancestors who were present in Europe before the Big Freeze.
An important European maternal clan 'HV' spread from Eastern into Northern and Western Europe, perhaps heralding the beginning of the Early Upper Palaeolithic 33,000 years ago. The HV clan is now widespread and fairly evenly distributed in Europe. H is the single, commonest line of all. It was not always so, and a specific sister cluster of the H clan, V, who were probably born in the Basque country, tells us why. The archaeology shows us how the south-western refuge of the Basque country drew cultures and presumably people down from north-west Europe during the lead-up to the Ice Age. Since Western Europe is separated from Italy by mountains, we would expect the reverse process after the Ice age as people re-expanded again from the Basque country and north along the Atlantic coast. This is exactly the picture left by the post-glacial spread of the maternal subgroup V, which has its highest frequency, diversity, and age in the Basque country, falling off as one goes north and only present in rather low frequencies in Italy. V arose in the Basque country shortly after the LGM. Her pre-V ancestor has been dated to 26,400 years ago, long before the LGM. Pre-V is still found farther east in the Balkans and Trans-Caucasus, consistent with her ultimate eastern origin. Even the post-glacial dates of expansion of V (16,300 years in the west) fit this scenario. Exactly the same pattern was seen for the Y-chromosome marker Ruslan, who we saw had moved into northern Europe from the east and found his home in Northern and Western Europe. The present-day picture shows Ruslan at his maximum frequency of 90 per cent in the Spanish Basque country, with the next-highest rates in Western and Northern Europe.
Italy, on the other hand, capped as it is by the Alps, was less a refuge for northern populations than a temperate region of continuous occupation by Mediterranean folk present from before the LGM. This is reflected again in the high proportion (over one-third of the total) of persisting preglacial mtDNA lines found in that region. We can see from these examples that the refuge zones are characterized by dramatic expansions of lines born locally in the refuge zones during the LGM, and also by high rates of persisting lines left over from the preglacial period. The latter pattern is certainly a feature of the Ukraine refuge, which as predicted by the archaeology retains 31 per cent of its preglacial maternal lines. A slightly less convincing case can be made for south-eastern Europeand the Balkans, which retained 24â26 per cent of preglacial lines.
It should be clarified that just because 20â34 per cent of modern European mtDNA lines have been retained from before the LGM, that does not mean that the rest of the lines found today had to have entered Europe from outside after the LGM. No, they were mostly locals. Of all modern European lines, 55 per cent originated in the period just after the ice age (the Late Upper Palaeolithic) but these, like the V haplogroup, probably derived from pre-existing European lines and simply reflect the post-glacial re-expansions from the refuges â in other words, new shoots off an old stock. Real fresh immigration into Europe from the Near East during the Neolithic period (from 8,000 years ago onwards) perhaps accounts for only 15 per cent of modern lines.
An interesting recent discovery about the genetic make-up of the south-eastern European region has to do with Y chromosome markers in Romania. The Carpathian Mountains were glaciated during the Ice Age and thus formed an effective, jagged barrier between south-eastern Europe and the regions bordering the Black Sea. This barrier splits Romania in two from top to bottom. Without their ice, the Carpathians hardly constitute an insurmountable physical barrier today, but they still mark a clear genetic boundary. This is revealed by Y-chromosome markers characteristic of north-eastern Europe and the Ukraine occurring at higher rates to the east of the Carpathians, while the markers more characteristic of Central Europe are found to the west. But this micro-regional boundary is very much obscured by the great dominance of the main Eastern European Y lineage M17, which may characterize the original preglacial Eastern Gravettian intrusions from the east. This lineage is found at very high rates throughout Eastern Europe â from Poland, through Slovakia and Hungary, to the Ukraine. M17 is still found at high frequencies among the Slavic peoples of the Balkans, which could support the existence of the Balkan ice-age refuge.
Again, in Northern Asia, the genetic record tells us that these hardy hunters of the permafrost retained some of their ancient maternal lines from before the LGM, and that there were subsequent expansions of certain subgroups after the thaw. MtDNA lines A, C, and Z are characteristic of North Asia, while D also extends farther south in China. Of these lines, A clearly survived from well before the LGM, as did various M and N lines. Then there was a gap of 10,000 years until about 17,000 years ago, before the re-expansion of lines such as variants of D, A, C, and finally Z.
<b>The genetics of North and Central Asia has simply confirmed what we might expect from the archaeology: when it got cold, the hunters of the Mammoth Steppe shrank in range and hunkered down, and when it got warm again they bounced back and reexpanded. The more interesting questions are what they looked like, and who their closest local descendants are today. Why and when did Mongoloids become the dominant types throughout most of Asia and the Americas? Does the genetic story tell us anything that cannot be inferred from the archaeological record?</b>
ICE AGE THE BIG FREEZE
As the Palaeolithic clock rolled on towards 20,000 years ago, however, events in the Earthâs spin axis and influences on its orbit hundreds of millions of kilometres away from our planet took tighter hold. Three great heavenly cycles of the solar system moved into a conjunction that ensured a minimum of the Sunâs heat reached the northern hemisphere during summer. The weather became colder, and the recurrent brief warm periods, or interstadials, which had characterized the period of 30,000â50,000 years ago, just stopped. It was these warm periods and their summer sunshine that had helped to melt the accumulated northern ice and prevent the ice caps from advancing across Scandinavia into Northern Europe. Now, the ice caps were able to expand in the north. The sea level started to fall again, eventually by 130 metres (430 feet). In short, the Earth was approaching its most recent ice age, or glaciation. (There had been quite a bit of ice on and off for the previous 100,000 years, and archaeologists tend to call the height of the Big Freeze the Last Glacial Maximum, or LGM for short, rather than an ice age.)
The LGM and its aftermath saw far more dramatic disruption and movement of northern human populations than at any time since. A glance at the world climate map around 18,000 years ago begins to give us the reason why. Huge areas of land became totally uninhabitable. For a start, the ice caps, some of them 5 km (3 miles) thick, clearly prevented the land they covered from being occupied. These white sheets were not laid evenly across the northern hemisphere. In Europe they mainly affected the central and northwestern regions. The British Isles, then part of the European mainland, were frozen down as far as Oxford in the south. Scandinavia will for ever bear the scars of the glaciers in its lakes and fjords and in the crustal depression now known as the Baltic Sea. Northern Germany, Poland, and the Baltic states bore the southern edge of the ice sheet, which extended north-east around the Arctic Circle across Finland and Karelia, into Archangel, and as far as the northern Urals. Farther south in Europe, mountainous regions such as the Pyrenees, the Massif Central, the Alps, and the Carpathians were ice-bound. As we shall see, however, Eastern Europe came off rather more lightly than the west. Asia fared rather better than Europe. Most of North and Central Asia remained ice-free. Just to the eastern side of the Urals, a large cap covered the Tamyr Peninsula and spread some way to the south. The other part of the continent which could have sported an ice cap was the huge Tibetan Plateau much farther south, its great elevation making it a very cold place. Even here there is some doubt of the extent of ice cover, since surprising forensic evidence of the presence of humans in Tibet dates back to the LGM.
North America was particularly severely affected, with Canada, the Great Lakes, and the north-eastern states â in other words the entire northern two-thirds of the continent â weighed down by two massive ice sheets that connected on the east with the Greenland ice cap. Alaska, on the other hand, was then connected to Siberia by a huge ice-less bridge of now submerged land, Beringia, and to some extent shared Asiaâs freedom from ice. The largest of the two American ice sheets, the Laurentide in the east, left its vast imprint as a deep dent in the Earthâs crust in the form of the great inland sea now known as Hudson Bay.
In some places, in both Eurasia and America, huge lakes (known as periglacial lakes) surrounded the ice caps. The best-known remnants of these lakes are the Great Lakes of North America. The ice sheets themselves were not static, but flowed like the glaciers they were. Not only did these frozen rivers grind out new valleys and fjords, they also obliterated much evidence that humans had ever lived in the north.
<i>Ice was not the only barrier to human occupation during the big freeze. The worldâs deserts expanded to an even greater extent. Around the ice caps, huge regions of North Eurasia and America became polar desert in which only the hardiest of plants and animals could survive. In Europe, the polar desert stretched east from the southern edge of England and due east across northern Germany, to the south of the Finno-Scandinavian ice sheet. The whole of the region from the Levant and the Red Sea to Pakistan, normally pretty dry, became a continuous extreme desert. Southern Central Asia, from Turkmenistan and Uzbekistan by the Caspian Sea in the west, through Xinjiang (north of Tibet), to Inner Mongolia in the east became continuous desert either side of the 40th parallel. This desert, which effectively replaced Guthrieâs Mammoth Steppe heartland, also split North and northern Central Asia from the whole of East and Southeast Asia.</i>
TOWARDS THE END OF THE JOURNEY
Ten Thousand years ago, at the end of the last Ice Age, the human population numbered only a few millions and all their food came from wild plants and animals. Then people began to domesticate some of those species, so that today almost the entire world population depends for food on a relatively small range of crops and domestic animals. During the 150,000 years that preceded the âagricultural revolutionâ, anatomically modern humans had colonized most of the globe and had learned to survive as foragers, subsisting on a great diversity of plant and animal foods. Foragers moved seasonally in small groups to obtain their food supplies and population densities remained low for many millennia.
Foraging to farming
By 8000 BC, some groups of foragers had settled down and occupied favourable sites year-round. Their populations increased, as restraints on fertility imposed by the seasonally mobile way of life were relaxed, and they ranged less far for their food. This profound change in human behaviour led to the beginnings of agriculture, enabling more people to be supported on a given area of land - although at the cost of the greater effort needed to cultivate crops and raise domestic animals. The effects of settling down, population increase, and growing dependence on agriculture led to increases in the number and size of settlements, to the development of more complex, less egalitarian societies, and, eventually, to urban life and civilization.
The earliest evidence of agriculture consists of the remains of wild species which have been altered in their morphology or behaviour by human intervention. Foremost among the crops are the cereals and pulses (peas, beans and other herbaceous legumes), the seeds of which provide carbohydrate and some protein and are easily stored. They sustained early civilizations and have become staples of world agriculture. They were domesticated from wild grasses in subtropical regions, for example wheat, barley, lentil, pea and chickpea in southwestern Asia; rice, soya and mung bean in southern and eastern Asia; sorghum, other millets and cowpea in tropical Africa; and maize and the common bean in Mexico. Root crops have also become staples in many areas, for example the potato which was domesticated in the Andes and is now a major crop of temperate latitudes, and manioc (cassava), yams, taro and sweet potato, all of which were native to the tropics.
Past 10,000 Years Developments in
Agriculture & Technology
10,000 B.P. First evidence of plant domestication. Enhanced monsoons 10K to 6K: wetter N. Africa, drier central N. America.
9,000 B.P. Flax in Syria and Turkey used for clothing (linen) and oil.
8,000 B.P. Beans used in eastern Mediterranean
7,000 B.P. Zea mays, squash, beans and peppers used in Americas
6,000 B.P. Cotton grown in Pakistan, cultivated grapes in Afghanistan
5,000 B.P. Soybeans, rice, wheat, barley and millet used in China
4,000 B.P. Olives, peaches and apricots cultivated in eastern Mediterranean
3,000 B.P. Phoenicians sail in the Mediterranean, while Polynesians sail the Pacific.
2,000 B.P. Sailors discover how to use monsoon patterns to their advantage.
1,000 B.P. 254-345 million Homo sapiens on the planet.
PRESENT Global Population est. 6.4 billion.
Domestication of animals
Whereas cereals and root crops were brought into cultivation and domesticated in all the habitable continents except Australia (where agriculture was introduced by European settlers in the 18th century AD), animals were domesticated in relatively few areas, principally in western Asia, where there is evidence for the early domestication of sheep, goats, pigs and cattle, followed later by asses, horses and camels. Some forms of cattle and pigs, as well as chickens, were domesticated in southern and eastern Asia, and cattle and pigs may also have been domesticated independently in Europe. Very few animals were domesticated in the Americas -turkey in North America and llama, alpaca and guinea pig in South America - and none in tropical Africa or Australia.
The spread of farming
Archaeological evidence indicates that the earliest transition to agriculture took place in the âFertile Crescentâ of southwestern Asia during the Neolithic period starting about 8000 BC. Sites in the Levant have yielded charred seeds and chaff of barley; wheat and various pulses, as well as the bones of domestic goats and sheep. Radiocarbon dating shows that grain cultivation began here about 1000 years before goat and sheep pastoralism. Dependence on agriculture increased very gradually, paralleled by the spread of village settlement, the development of techniques of irrigation and terracing, and the cultivation of fruits such as dates, figs, grapes and olives. By the end of the Neolithic in southwestern Asia, about 6000 years ago, agriculture had spread west and east into Europe, northern Africa and central and southern Asia, where new domesticates were added to the growing repertoire of crops.
<b>Agriculture began independently in China between 7000 and 6000 BC, in the Americas by about 3000 BC and in tropical Africa by about 2000 BC. By the time of the European expansion in the 16th century AD agricultural and pastoral economies occupied most of Eurasia, Africa and Central and South America.</b>
PEOPLING OF THE WORLD
In all our cells we have genes. Genes are made up of DNA, the string-like code of life that determines what we are, from our fingernails to our innate potential for playing the piano. By analysing genes, we can trace the geographic route taken by our ancestors back to an ultimate birthplace in Africa, at the dawn of our species. Further, if we take any two individuals and compare their genes, we will find that they share a more recent ancestor - living, in all probability, outside Africa. What is more, I believe that we can now prove where those ancestors lived and when they left their homelands. This remarkable proof has become fully possible only within the last decade, as a result of pioneering work by a number of people.
Many of us have wondered what we would find if we could perhaps board a time machine and travel back through the generations of our ancestors. Where would it take us? Would we find ourselves to be distantly related to some famous or notorious person? How many generations would we pass through before we arrived at the first humans? Does our line continue back to monkeys, and beyond to worms and single-celled creatures, as Darwin maintained? We know from dry biology lessons at school that this ought to be so, but as with the uncertainty of what happens to us after we die, it is hard to fully grasp.
We are now so used to the pace of technical advances that the sense of wonder fades with each new one. Yet, until very recently, geneticists could only dream of using our genes to trace the detailed history of how we conquered the world. The reason for their pessimism was that the majority of the genes they examined shuffled themselves around at each generation and were common to most populations anyway. Their task was like trying to reconstruct a previously played card game from the pack of cards after it has been shuffled. So it was nearly impossible to draw an accurate genetic family tree going back even a few hundred years, let alone back to the beginning of our species. Most human populations look very similar beneath the skin, so where could one start?
The use of gender-specific gene lines, the so-called Adam and Eve genes, has in the last ten years changed all that. In contrast to all other genes, mitochondrial DNA (a collection of genes outside the cell nucleus) is inherited only through our mothers, and the Y chromosome is inherited only by men. These two sets of gender-linked genes are passed on unchanged from generation to generation, with no shuffling, and can therefore be traced right back to our ancestors, to the first Primates. We can thus construct two family gene trees, one for our fathers and one for our mothers. As a result, in any population, of whatever size, we can trace any two individuals through one of these two gene trees back to a most recent shared ancestor on the tree. Such an ancestor may have lived 1,500 or 150,000 years ago, but all ancestors can be assigned a place on the newly constructed Adam-and-Eve genetic trees. These are real family trees of modern human gene lines, with real branches. Each branch on each tree can be dated (although the accuracy of such dating still leaves much to be desired).
Many regional human gene trees have now been fitted together, like a large jigsaw that is started by assembling the edges using certain clear landmarks. In this way, a picture of the Adam-and-Eve gene lines spreading from Africa to every corner of the world has been pieced together over the last decade. It has got to that satisfying point, as with jigsaws, when the whole structure suddenly links up and takes shape; the remaining pieces, though many, are now being placed on the tree and on the map with increasing ease and speed. <b>The pace is now so rapid that people working at the cutting edge on one geographic region may still be unaware of breakthroughs in another region. The whole branching tree can now be laid flat on a world map to show where our ancestors and their gene lines travelled in their conquest of the world.</b>
The new knowledge has resolved some of the apparent paradoxes thrown up by the contrast between the cultural and biological stories of the last 150,000 years. We can now even start to hang the regional human fossil relics of that period in their correct places on the genetic tree of life.
Many questions have been answered. It turns out that, far from the world being a common genetic melting pot with massive to-and-fro prehistoric movements and mixings, the majority of the members of the modern human dispersal have conservatively stayed put in the colonies their ancestors first established. They have dwelt in those localities since well before the last ice age. We can also trace the dates of specific migrations over the last 80,000 years. Thus, from a picture of great diversity and lack of definition, we have the opportunity to move to a highly specific and regional focus on the branching networks of human exploration.
Several other obvious examples of long-standing archaeological questions have been resolved by the new gene trees. One is the 'Out-of-Africa' v. 'Multiregional' controversy.
The Out-of-Africa view is that all modern humans outside Africa descend from a recent movement from Africa less than 100,000 years ago. This exodus wiped out all earlier human types around the world. The multi-regionalists, in contrast, argue that the archaic human populations, Homo neanderthalenis (Neanderthals) in Europe and Homo erectus in the Far East, evolved into the local races we now see around the world.
The Out-of-Africa view now wins the contest because the new genetic trees lead straight back to Africa within the past 100,000 years. No traces of Adam-and-Eve gene lines from older human species remain on our genetic tree, except of course at the root, from which we can measure our genetic distance from Neanderthals. Neanderthals have now been genetically typed using ancient mitochondrial DNA, and it seems that they are our cousins rather than our ancestors. We share with them another common ancestor, Homo helmei.
Current Out-of-Africa proponents have usually hedged their bets, claiming that Australians, Asians, and Europeans came as separate migrations of Homo sapiens from Africa. Not so: the male and female genetic trees show only one line each coming out of Africa. There was only one main exodus of modern humans from Africa - each gender line had only one common genetic ancestor that respectively fathered and mothered the whole non-African world.
<b>Other prejudices have also foundered. Some European archaeologists and anthropologists have long held that Europeans were the first to learn to paint, carve, develop complex culture, and even to speak almost as if Europeans represented a major biological advance. The structure of the genetic tree denies this view. Australian aboriginals are related to Europeans, and share a common ancestor just after the exodus from Africa to the Yemen over 85,000 years ago. Thereafter they moved progressively round the coastline of the Indian Ocean, eventually island-hopping across Indonesia to Australia where, in complete isolation, they developed their own unique and complex artistic cultures. The first Australian rock art has been dated at least as early as the first European one.</b>
Another old archaeological controversy concerns the spread of the Neolithic culture across Europe from Turkey 8,000 years ago. Did the farmers from the Near East wipe out and replace the European hunters, or did the new ideas spread more peacefully, converting the pre-existing Palaeolithic hunter-gatherer communities? The genetic answer is clear: 80 per cent of modern Europeans descend from the old hunter-gatherer gene types, and only 20 per cent from Near Eastern farmers.
Finally, moving to the other side of the world, there has always been colourful speculation over the origins of the Polynesians. Thor Heyerdahl was not the first (in fact, Captain Cook was nearer the mark in arguing for a Polynesian link to the Malay archipelago). For the past fifteen years archaeologists have thought that Polynesians came from Taiwan. The genetic tree discounts this now: the ancestors of the sailors of the great canoes started out further along the trail, in Eastern Indonesia.
We should remember that we are participants in this genetic story, since 99 per cent of the work of reconstruction of our ancient gene trees was carried out using modern DNA given voluntarily by people living in different parts of the world today. This is a story of relevance to each and everyone of us.
Many Anthropologists now say that we came out of Africa, but how do they know? If we all have a single recent origin there, why do there appear to be different races of humans? How closely are these races related? Are we all part of one family, or do Africans, aboriginal Australians, Europeans, and East Asians all have different parallel evolutionary origins? What key forces in our evolutionary history took descendants of apes that had just left the trees to walk the African savannah and catapulted them onto the Moon within a couple of million years?
DNA analysis has led to extraordinary advances in our understanding of the regional biological history of modern humans. The so-called Adam and Eve genes really do allow us to track back in time and space to follow the human family in its wanderings in Africa and then round the globe over the past 200,000 years.
Much of the human history of the past 2.5 million years has been reconstructed by a combination of studies of fossil bones and past climates. All but one human species became extinct, some of them long ago, so we do not have their living genes to study.
To say that there are no genes left over from past human species is, however, not quite true. Most of our nuclear genes are inherited nearly intact from ancestral humans and apes. Some human genes can be found in several forms that split from one another long before Homo sapiens appeared on Earth. Scientists have also extracted short fragmentary stretches of mitochondrial DNA from a number of Neanderthal bones, and are now in a position to answer basic questions about how closely we are related to them and whether there are any of their genes left in modern human populations.
However, the real revolution in understanding human genetic prehistory covers the last 200,000 years, which is what concerns us here. For this period, the new genetics has shone a bright light onto a controversial field previously dominated by collections of European and African stone tools and a few poorly dated skeletal remains.
Within each of the cells of our bodies we all have incredibly long strings of DNA. It is the stuff of the genes. It stores, replicates, and passes on all our unique characteristics â our genetic inheritance. These DNA strings hold the template codes for proteins, the building blocks of our bodies. The codes are âwrittenâ in combinations of just four different chemicals known as nucleotide bases (represented by the letters A, G, C, and T), which provide all the instructions for making our bodies. We inherit DNA from each of our parents, and because we receive a unique mixture from both, each of us has slightly different DNA strings from everyone else. Our own DNA is like a molecular fingerprint.
<img src='http://www.bradshawfoundation.com/journey/images/gene-diagram3.gif' border='0' alt='user posted image' />
The diagram above shows the drawing of
gene trees using single mutations
During human reproduction, the parentsâ DNA is copied and transmitted in equal proportions. It is important to know that although most of the DNA from each parent is carefully sorted during reproduction, small bits of their respective contributions are shuffled and mixed at each generation. This splicing and mixing is known technically as recombination and makes it more difficult to trace back our genetic prehistory in those genes. Luckily, for the purposes of genetic researchers, there are two small portions of our DNA that do not recombine. Non-recombining DNA is therefore easier to trace back since the information is uncorrupted during transmission from one generation to the next. These two portions are known as mitochondrial DNA (mtDNA) and the non-recombining part of the Y chromosome.
If India was empty when the aryans invaded then who were the people of the Indus valley civilization?
I find the discussion puzzling. Votaries of Aryan invasion or migration theory suggests that these people came into the Indian subcontinent about 3500 years ago. How can India be empty 3500 years ago?
Could you please update the link that you posted ? Somehow it gives me an error.. <!--emo&
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Can knowledgeable folks please answer the foll questions ?
<!--QuoteBegin-->QUOTE<!--QuoteEBegin-->Indians appear to display the higher diversity both in haplogroups 3 and 9 -- even if a pooled sample of eastern and southern European populations was considered.<!--QuoteEnd--><!--QuoteEEnd-->
What does this mean ? What does "higher diversity" mean ?
<!--QuoteBegin-->QUOTE<!--QuoteEBegin-->By the end of the Neolithic in southwestern Asia, about 6000 years ago, agriculture had spread west and east into Europe, northern Africa and central and southern Asia, where new domesticates were added to the growing repertoire of crops.
Agriculture began independently in China between 7000 and 6000 BC, in the Americas by about 3000 BC and in tropical Africa by about 2000 BC. By the time of the European expansion in the 16th century AD agricultural and pastoral economies occupied most of Eurasia, Africa and Central and South America.<!--QuoteEnd--><!--QuoteEEnd-->
How do we know this ? When did agriculture start in south asia ? Was it independent ? In general my understanding of the AIT/AMT proponents' argument is that an invasion happened some 4-5k yrs ago ? How does this new info refute that ? After the migration out of India towards Europe so many years ago and being cutoff for some time couldnt they have just come back ? I read somewhere that some markers were more prominent towards southeast of India while some others were more prominent towards north-west. How does this new finding refute that ? I am not molecular biologist so please bear with me.. <!--emo&
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Sorry one more basic question..
<!--QuoteBegin-->QUOTE<!--QuoteEBegin-->In contrast to all other genes, mitochondrial DNA (a collection of genes outside the cell nucleus) is inherited only through our mothers, and the Y chromosome is inherited only by men. These two sets of gender-linked genes are passed on unchanged from generation to generation, with no shuffling, and can therefore be traced right back to our ancestors, to the first Primates. We can thus construct two family gene trees, one for our fathers and one for our mothers.<!--QuoteEnd--><!--QuoteEEnd-->
When we say mtDNA is inherited only through mothers - does it change and given that it doesnt get shuffled with fathers DNA the changes are just replication errors ? Coz if mtDNA and Y chromosome gets directly copied over to the newborn then wouldnt we have the same exact Y chromosome and mtDNA ? There must be some process for change here. Given that there is how do people recognise that P is daughter (say) of Q ?
Can knowledgeable folks please answer the foll questions ?
Indians appear to display the higher diversity both in haplogroups 3 and 9 -- even if a pooled sample of eastern and southern European populations was considered.
What does this mean ? What does "higher diversity" mean
Higher Diversity means root stock and earlier origin
Which means Indians are ancestors of Haplogroups 3 and 9
10-28-2004, 09:49 AM
(This post was last modified: 10-28-2004, 01:41 PM by dhu.)
Email me for the kivislid file.
Higher diversity means more variation in the genetic sequence among individuals of the population. Any population with greater diversity for any given gene sequence is more likely to be an original source group - whereas - any population with comparatively lesser diversity is more likely to be a derived group (from the source group).
If a small group of humans left Earth to set up a colony on Mars, then a thousand years down the road we could still easily tell which planet was the original human home. Earth's human population would be very diverse - whereas - Mars' population would reflect only the limited diversity of the original few colonists
Since Both mtDNA and y chromosome lack a corresponding homologous pair, I don't think these regions undergo recombinant translocation in the same way that autosomes do. Their variation is solely due to mutations which accumulate over time. The sequences used to track diversity are in the noncoding regions (introns, junk sequences, repeats, etc) of DNA, eliminating the effects of selective pressure on the actual genes.
This new evidence extrapolates into prehistory the well-known civilizational gradient between India/China and the joker settlements of Europe. The population and cultural trajectories are overwhelimingly East to West and they have always been that way. There is simply no question of some euro pinecone laying the foundation of Dharma in India and it sister region of SE Asia........
Dhu, please check email.
10-29-2004, 03:33 PM
(This post was last modified: 10-29-2004, 03:46 PM by dhu.)
Oppenheimer basically proves that the entire cultural and technological complex of North Europe (Vikings, etc) is originally derived from the much antecedent cultures of SE Asia. some examples:
borgun stave church, Norway
<img src='http://www.bow.k12.nh.us/cyberBUS/vikings/Viking%20Pictures/stave%20church%20in%20Borgund%20Norway.jpg' border='0' alt='user posted image' />
Batak House, Indonesia
<img src='http://www.burtonbradstock.org.uk/History/Lionel%20Bailey%20wartime/Sumatra.jpg' border='0' alt='user posted image' />
<img src='http://www.floressa-bali.com/tour-catalog/assets/images/batakhouse.JPG' border='0' alt='user posted image' />
Basically, we are seeing that SE asians expanded over the sea to give rise to the maritime cultures of the west including sumeria.... while the Indians trekked into their backyard, aka the asian interior, to give rise to Parsis, Mittanis, Kurds, Central Asians and their minor barbarian cousins, the greeks and Russis......
If anything, the Indians originated in SE Asia.. no way in the tundra wastelands of the west
The integrative potential of these discoveries is enormous as it places the center of Dharma in Orissa, Assam, and thereabouts, which missionaries are trying to manufacture into a breaking point...
<!--QuoteBegin-->QUOTE<!--QuoteEBegin-->The integrative potential of these discoveries is enormous as it places the center of Dharma in Orissa, Assam, and thereabouts, which missionaries are trying to manufacture into a breaking point...
An eastern Indian origin for Sanatana Dharma is interesting.
Most of puranas have a distinctly eastern flavor, so this could be correct.
On a side note, where did the europeans get blue eyes & blonde hair from?
Is it from mixing with the Finno-ugric race?
The center of blondism in Europe is the east baltic sea (Finland, poland, lithuania, lativa and NW Russia). It is not in Germany as is popularly believed.
So the Aryans may have invaded Europe from the east and mixed with a blonde aboriginal race and created the modern European.
<!--QuoteBegin-->QUOTE<!--QuoteEBegin-->On a side note, where did the europeans get blue eyes & blonde hair from?
Is it from mixing with the Finno-ugric race?
The center of blondism in Europe is the east baltic sea (Finland, poland, lithuania, lativa and NW Russia). It is not in Germany as is popularly believed.
So the Aryans may have invaded Europe from the east and mixed with a blonde aboriginal race and created the modern European.<!--QuoteEnd--><!--QuoteEEnd-->
you dont have to mix races to get new traits....!!
The colder climate in Europe and less sun shine selects those mutants who can survive in these conditions, Less melanin means more absorbance of sunshine to make essential Vitamin D. The leptorhine (long, straight nose) is also a survival strategy, as dry and cold air is not good, the nose warms and moistens it before it goes to lungs. The tropical country people generally have smaller, broader nose as they didnt have to develop noses to moisten the air (because of lot of humidity) It will take just 30 to 40 generations for all these to change.
The Gobi desert in china reflects sunlight a lot, so the high cheek bones of chinese makes better survival strategy. Same is true with the people living in places with lots of ice (eskimos).
The sub saharan africa has lot of savannahs, the people there are tall, thin and black (the Masai). Tall thin body makes them easy to lose body heat. And when walking upright less surface area is exposed to sun.
There is no different race of human beings...! All are 99.99% alike...
Long gone are those 19th century ideas of Aryan race, non aryan race!!
Welcome to 21st century.
Can anyone readup on Puranas and Ramayana and figure out the impact of Mt Toiba eruption? Was that the begining of the flood myth that was carried through early society? Also waht about thenew homonid discovered in Indonesia? Does it relate to Ramayana figures?
bengurion, dhu and other guroos,
More basic questions..
<!--QuoteBegin-->QUOTE<!--QuoteEBegin-->It will take just 30 to 40 generations for all these to change.<!--QuoteEnd--><!--QuoteEEnd-->
30-40 generations would mean about 800-1000 years ? How do we know that is the time it takes.
Also now i understand a little bit about how mtDNA can quantify (?) diversity but how does the dating work ? Looking at an mtDNA sequence how do people know the age of that sequence ? Is it something like carbon-dating ? Or is it combined with archeology ?
Thanks once again for earlier answers, guys.
The first avatar is the matsya avatar
Wherein vishnu takes a small group of survivors on a boat after a flood
I posit that this flood was circa 8500 years ago, when the last submerging of Sundaland occured
I saw the DVD version of the Oppenheimer book
They said it takes 20000 years for an African to morph into a European