So suggests new research that tracked changes in two genes thought to help regulate brain growth, changes that appeared well after the rise of modern humans , years ago. That the defining feature of humans — our large brains — continued to evolve as recently as 5, years ago, and may be doing so today, promises to surprise the average person, if not biologists. Lahn and colleagues examined two genes, named microcephalin and ASPM, that are connected to brain size.
If those genes don't work, babies are born with severely small brains, called microcephaly. Using DNA samples from ethnically diverse populations, they identified a collection of variations in each gene that occurred with unusually high frequency. In fact, the variations were so common they couldn't be accidental mutations but instead were probably due to natural selection, where genetic changes that are favorable to a species quickly gain a foothold and begin to spread, the researchers report.
Lahn offers an analogy: Medieval monks would copy manuscripts and each copy would inevitably contain errors — accidental mutations. Years later, a ruler declares one of those copies the definitive manuscript, and a rush is on to make many copies of that version — so whatever changes from the original are in this presumed important copy become widely disseminated.
Scientists attempt to date genetic changes by tracing back to such spread, using a statistical model that assumes genes have a certain mutation rate over time. For the microcephalin gene, the variation arose about 37, years ago, about the time period when art, music and tool-making were emerging, Lahn said.
For ASPM, the variation arose about 5, years ago, roughly correlating with the development of written language, spread of agriculture and development of cities, he said. Other scientists urge great caution in interpreting the research. That the genetic changes have anything to do with brain size or intelligence "is totally unproven and potentially dangerous territory to get into with such sketchy data," stressed Dr. Aside from not knowing what the gene variants actually do, no one knows how precise the model Lahn used to date them is, Collins added.
Lahn's own calculations acknowledge that the microcephalin variant could have arisen anywhere from 14, to 60, years ago, and that the uncertainty about the ASPM variant ranged from to 14, years ago. Those criticisms are particularly important, Collins said, because Lahn's testing did find geographic differences in populations harboring the gene variants today.
They were less common in sub-Saharan African populations, for example. That does not mean one population is smarter than another, Lahn and other scientists stressed, noting that numerous other genes are key to brain development. The work was funded by the Howard Hughes Medical Institute. The information contained in the AP News report may not be published, broadcast, rewritten or redistributed without the prior written authority of The Associated Press. Language tree rooted in Turkey Evolutionary ideas give farmers credit for Indo-European tongues.
The finding hints that farmers in what is now Turkey drove the language boom - and not later Siberian horsemen, as some linguists reckon. Russell Gray and Quentin Atkinson, of the University of Auckland in New Zealand use the rate at which words change to gauge the age of the tree's roots - just as biologists estimate a species' age from the rate of gene mutations.
The differences between words, or DNA sequences, are a measure of how closely languages, or species, are related. Gray and Atkinson analysed 87 languages from Irish to Afghan. Rather than compare entire dictionaries, they used a list of words that are found in all cultures, such as 'I', 'hunt' and 'sky'. Words are better understood than grammar as a guide to language history; the same sentence structure can arise independently in different tongues.
The resulting tree matches many existing ideas about language development. Spanish and Portuguese come out as sisters, for example - both are cousins to German, and Hindi is a more distant relation to all three.
All other Indo-European languages split off from Hittite, the oldest recorded member of the group, between 8, and 10, years ago, the pair calculates 1. Around this time, farming techniques began to spread out of Anatolia - now Turkey - across Europe and Asia, archaeological evidence shows.
The farmers themselves may have moved, or natives may have adopted words along with agricultural technology. The conclusion will be controversial, as there is no consensus on where Indo-European languages came from. Some linguists believe that Kurgan horsemen carried them out of central Asia 6, years ago. It shows how ideas about language evolution can be tested, she says: There is lots of word-swapping within language groups. English took 'skirt' from the Vikings, for example, but 'shirt' is original.
Linguists must separate the shared from the swapped, as any error will affect later studies. The Kurgan might not be out of the picture entirely, says McMahon - they may have triggered a later wave of languages.
Language-tree divergence times support the Anatolian theory of Indo-European origin. Nature, , - , doi: Earlier that morning I had set out on a pilgrimage to the Exalted Throne of Yahweh where Adam's god dwelt. Within an hour the noise and chaos of Tabriz had been left far behind, as our four-wheel drive ascended out of the alpine valley of the Adji Chay onto the plateau of the Sahand massif, with imposing volcano at its heart.
Now I found myself at the entrance to one of our world's most extraordinary places - the troglodyte village of Kandovan.
Ambling down the cobbled street - only just wide enough to take a donkey and cart - I turned up a steep side alley, all the time stalked by a clutch of free-roaming chickens. The alley soon morphed into a roughly sculpted flight of steps which twisted and turned between huge canine teeth of lava.
Each was a home - a dwelling from a bygone age with rickety wooden door and tiny mullioned windows. In this Dysneyesque landscape of cave-dwellers, I almost expected Pinocchio to appear around the next bend. Kandovan - 'The Honeycombe'.
My long journey, starting in the research libraries of London University, had led me to the Mesopotamian flood plain and on up into the mountains of Kurdistan, finally to reach the place the Book of Genesis calls the Garden of Eden. There is no straightforward way to explain how an Egyptologist, used to working in the dry heat of the north African deserts, should end up traversing the Zagros mountains of western Iran in search of the earthly paradise. I had begun my studies in the Departments of Egyptology and Ancient History at University College, London, with a major interest in the complex chronology of Egyptian civilisation.
My PhD work to radically revise that chronology had inevitably drawn me into the world of biblical history - so closely bound up with the land of the pharaohs. Years of research had led me to the conclusion that many of the stories in the Old Testament were based on real historical events: But why was I now delving into the Book of Genesis - that most mythological and hoary of the biblical texts?
Surely it would have been better to leave well alone? But that is not my way. The simple fact is that ancient stories and legends have always fascinated me and the chance to uncover the historical reality behind the greatest legend of them all was just too tempting an opportunity to pass by.
The 'Temptation Seal' on display in the British Museum. Back in I had been sent a short, privately published paper by amateur historian, Reginald Walker , which proposed a location for the Garden of Eden in north-western Iran.
The main thrust of Walker's argument was that the four rivers of Eden, described in Chapter Two of Genesis, were to be found in that region. All four had their sources the Bible refers to them as 'heads' around the two great salt lakes of Van and Urmia. Ever since the time of the Jewish historian Josephus, a near contemporary of Christ, scholars have tried to use Genesis 2 to locate Eden. But the problem has always been the identification of the rivers themselves.
The first two are no problem: The remaining two rivers, however, have always been a mystery. Clearly, in order to locate Eden precisely, we need to find the sources of all four - and that's where Walker's research comes in. By checking the writings of the Islamic geographers who accompanied the Arabic invasion of Persia in the 8th century, I was able to confirm that this was indeed the case. Moreover, even as late as the last century, Victorian atlases and encyclopaedias were still naming the river as the Gaihun-Aras.
The Gaihun is therefore the missing biblical Gihon. The fourth river - the Pishon - was more difficult to find. Walker suggested that this Hebrew West Semitic name derived from the old Iranian Uizhun, where the Iranian vowel 'U' had been converted into the Semitic labial consonant 'P'. Thus we have Uizhun to Pizhun to Pishon. Strange as it may seem, such switches do occur between the two language groups.
For instance, one archaeological site in Iran is known by its Arabic West Semitic name of Pisdeli whereas its ancient Iranian name was Uishteri.
The river Uizhun the modern Qezel Uzun - thus identified as the biblical Pishon - flows down from the mountains of Kurdistan and empties into the southern basin of the Caspian Sea. The four rivers of Eden. Bringing all this together we find that the sources of all four rivers originate in the highland area which Alexander the Great knew as Armenia and we know today as eastern Turkey and western Iran. A crucial line in the epic describes the envoy descending from the last of the seven mountain passes the Sumerians called them 'gates' and crossing a broad plain before arriving at the city of Aratta with its red-painted city wall.
The envoy, journeying to Aratta, covered his feet with the dust of the road and stirred up the pebbles of the mountains. So, combining Walker's discovery of the four rivers together with the Sumerian location of Eden, it seemed as though the whereabouts of the lost Eden and its fabled garden was near to being resolved. I decided to set out for the ancient city of Susa burial place of Daniel of the lions' den in the south-western flood plain of Iran Iraq was off bounds for obvious reasons from where I determined to retrace the Sumerian envoy's route to paradise.
Following the ancient track through the seven 'gates', I eventually reached the Miyandoab plain to the south of Lake Urmia. The journey had taken four days by car but would have taken the envoy the best part of four months by donkey.
The edin remains today one of the lushest regions of the Middle East: This, I am sure, was the original heart of Eden which, over time, became a much wider area, including both the salt lakes and the Garden of Eden itself. The Bible describes the latter as being 'east in Eden' - in other words to the east of but still within the wider territory of Eden.
My driver and I continued eastwards, between the south-eastern shore of Lake Urmia and the towering volcanic peak of Mount Sahand. An hour's drive along the highway brought us into a long west to east valley, the slopes of which were terraced with 'every kind of tree' smothered in spring blossom God planted a garden in Eden, which is in the east, and there he put the man he had fashioned.
From the soil, God caused to grow every kind of tree, enticing to look at and good to eat. The nearest mountain to the north glowed bright red in the low evening light - a pile of pure red ochre. At its foot sprawled the regional capital of Tabriz, squatting at the centre of the valley where Adam and Eve whoever they were once lived according to biblical tradition. The first thing which came to mind was paradise lost. Nothing of the earthly garden and its settlement could have survived beneath these bustling streets.
But then, away from the city, I soon discovered that there was much that remains of Adam's Neolithic culture. Paradise Lost - the sprawling city of Tabriz. This was the region where Man first began to settle down to sedentary life; where he learnt to domesticate animals and plant his crops; and where he began to bury his dead in graves, the bones painted in red-ochre. Adam's name means the 'red-earth' man.