One Common Ancestor Behind Blue Eyes
By Jeanna Bryner, LiveScience Staff Writer
People with blue eyes have a single, common ancestor, according to new research.
A team of scientists has tracked down a genetic mutation that leads to blue eyes. The mutation occurred between 6,000 and 10,000 years ago. Before then, there were no blue eyes.
"Originally, we all had brown eyes," said Hans Eiberg from the Department of Cellular and Molecular Medicine at the University of Copenhagen.
The mutation affected the so-called OCA2 gene, which is involved in the production of melanin, the pigment that gives color to our hair, eyes and skin.
"A genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a 'switch,' which literally 'turned off' the ability to produce brown eyes," Eiberg said.
The genetic switch is located in the gene adjacent to OCA2 and rather than completely turning off the gene, the switch limits its action, which reduces the production of melanin in the iris. In effect, the turned-down switch diluted brown eyes to blue.
If the OCA2 gene had been completely shut down, our hair, eyes and skin would be melanin-less, a condition known as albinism.
"It's exactly what I sort of expected to see from what we know about selection around this area," said John Hawks of the University of Wisconsin-Madison, referring to the study results regarding the OCA2 gene. Hawks was not involved in the current study.
Eiberg and his team examined DNA from mitochondria, the cells' energy-making structures, of blue-eyed individuals in countries including Jordan, Denmark and Turkey. This genetic material comes from females, so it can trace maternal lineages.
They specifically looked at sequences of DNA on the OCA2 gene and the genetic mutation associated with turning down melanin production.
Over the course of several generations, segments of ancestral DNA get shuffled so that individuals have varying sequences. Some of these segments, however, that haven't been reshuffled are called haplotypes. If a group of individuals shares long haplotypes, that means the sequence arose relatively recently in our human ancestors. The DNA sequence didn't have enough time to get mixed up.
"What they were able to show is that the people who have blue eyes in Denmark, as far as Jordan, these people all have this same haplotype, they all have exactly the same gene changes that are all linked to this one mutation that makes eyes blue," Hawks said in a telephone interview.
The mutation is what regulates the OCA2 switch for melanin production. And depending on the amount of melanin in the iris, a person can end up with eye color ranging from brown to green. Brown-eyed individuals have considerable individual variation in the area of their DNA that controls melanin production. But they found that blue-eyed individuals only have a small degree of variation in the amount of melanin in their eyes.
"Out of 800 persons we have only found one person which didn't fit — but his eye color was blue with a single brown spot," Eiberg told LiveScience, referring to the finding that blue-eyed individuals all had the same sequence of DNA linked with melanin production.
"From this we can conclude that all blue-eyed individuals are linked to the same ancestor," Eiberg said. "They have all inherited the same switch at exactly the same spot in their DNA." Eiberg and his colleagues detailed their study in the Jan. 3 online edition of the journal Human Genetics.
That genetic switch somehow spread throughout Europe and now other parts of the world.
"The question really is, 'Why did we go from having nobody on Earth with blue eyes 10,000 years ago to having 20 or 40 percent of Europeans having blue eyes now?" Hawks said. "This gene does something good for people. It makes them have more kids."
Find may shed light on Roman era
A team of archaeologists from the University of Exeter has found a Roman fort dating from the 1st Century AD in fields in Cornwall.
Several items of pottery have been excavated and a furnace which may have been used to smelt minerals.
Researchers said the find at Calstock, close to a silver mine, could show for the first time the Romans' interest in exploiting Cornish minerals.
Very little is known so far about the Roman occupation in Cornwall.
The discovery could therefore mark an important step in piecing together this period of history.
Archaeologists became interested in the site when they found references in medieval documents to the smelting of silver "at the old castle" and "next to the church" in Calstock.
The team conducted a geophysical survey, which clearly showed the outline of a feature of a similar shape to another Roman fort recently found near Lostwithiel.
They started digging and found the shape of a Roman military ditch.
University of Exeter archaeologist Dr Stephen Rippon said: "The Roman army only stayed in the South West for a few decades after the Conquest, before moving on to Wales.
"This find could help us to understand whether they were merely keeping watch over the locals, or were actually interested in exploiting commercial opportunities in the region."
The two other known sites of Roman forts in Cornwall are also in the south east of the county.
One was discovered last year near Restormel Castle, Lostwithiel, and the other is at Nanstallon, near Bodmin.
Both sites are close to mineral deposits in areas associated with tin mining.
Putting the clock back 10,000 years
02/02/2008 12:29:48 AM EST
WESTERN DAILY PRESS
Chock-full of famous Roman Baths, Celtic kings, Georgian crescents and Jane Austen, the history of Bath already ran to quite a weighty tome.
But archaeologists admitted yesterday that two new chapters would have to be written after amazing discoveries made while a new sewer was being dug.
At the very depths of the site of a new GBP350 million shopping centre in the heart of the ancient city, archaeologists found new evidence that extends the history of the city thousands of years further back.
The archaeologists found the first evidence of human activity near the banks of the River Avon dating back to 8,000BC, that's before any kind of recorded history and even before the idea of farming had reached the British Isles.
The first Bathonians were hunter- gatherers, following herds of deer and other game along the river valley, attracted by the hot springs and the plentiful fish in the River Avon.
And on the spot where people would later settle and use the hot springs, they made tools, fished and left scraps of archaeological evidence, according to Bath and North East Somerset archaeologist Richard Sermon.
"Previously, archaeological interest has been on the Roman and medieval times in Bath, but this has given us a glimpse right back into the very first people who would have come to what is now Bath," he said.
"The hunter-gatherers would have been attracted by the game here and the fishing, and possibly by the micro-environment caused by the hot springs. It takes the history of Bath right back to 8,000BC.
"It's not perhaps rewriting the history of Bath, but giving us a new chapter. It tells us that people came here that long ago. Flint tools and other items were found in the alluvial deposits." The archaeologists also found evidence that Alfred the Great viewed Bath as part of his chain of fortified towns right across southern England, as he built a line of defences against the Danes.
Back in 880, two years after Alfred returned from the Somerset marshes to defeat the Danes and push them out of Wessex, he ordered a chain of towns to have their defences beefed up. So such towns as Malmesbury and Cricklade in Wiltshire, and Barnstaple in Devon became effectively huge castles with defensive ramparts to repel any Viking invasion.
And while Bath's Dark Age history has remained elusive, Mr Sermon said the exciting evidence showed that Bath was part of his plans too.
"Here we have found evidence of a very early ditch which would have been defensive and crossed where Southgate Street later ran.
"It was actually found while work went on to construct a combine sewer outfall for the new shopping centre. We dated it and discovered it was late Saxon, which would match the defensive work in other places at the time of King Alfred," he added.
The evidence for new chapters in Bath's history has captured the imagination of 21st-century Bathonians. A lecture held last month in which the archaeologists revealed their findings, was so popular people had to be turned away.
So heritage bosses are holding a repeat on Monday, February 11, at 7pm in the Guildhall.
Prehistoric finds at motorway dig
New evidence of prehistoric life has been discovered during motorway excavations in Merseyside.
A team of archaeologists found flints and burnt hazelnuts during preparations for a new junction of the M62.
The archaeological findings date from the Mesolithic to the Bronze Age periods - around 5000 to 2000 BC.
The pieces were found while the excavations were being carried out for a new link road at Junction six near Huyton.
Ron Cowell, curator of prehistoric archaeology at Liverpool Museum, said the find is among the oldest in Merseyside, Cheshire and Lancashire.
He said: "Discoveries of settlements like this are quite common in upland areas like the Peak District but in lowland places, which have been farmed for centuries and built upon time and again, it is very exciting."
In total, the dig recovered more than 3,000 objects ranging from prehistoric to Roman, including pottery and tiles that were made for the 20th Roman Legion based in Chester around 167 AD.
The site was not important enough to block the motorway scheme and it is once again buried - below the new £38m Junction 6 at Tarbock Island.
Gary Hilton, Highways Agency project manager, said: "The Highways Agency takes its responsibility for our heritage very seriously and we are delighted to have found this window into the past."
The artefacts will now go on public display at Liverpool's World Museum.
Viking burial site found
By Martin Herron
ONE of South Yorkshire's most significant archaeological finds ever has been unearthed during work to build a multi-million pound special school.
Experts have discovered the remains of 35 ancient bodies - thought to be Vikings or Saxons - in a burial site which could date back as far as the fifth century.
They have been found as part of site preparations for the construction of the new North Ridge Community School in Adwick, in the grounds of North Doncaster Technology College.
The first three bodies were found by archaeologists called in to carry out a site survey. The work was intended to make sure nothing of archaeological interest would be destroyed by the building work.
Archaeologists have now recovered 35 bodies in total, believed to be Anglo-Saxon, from what is thought to be an ancient cemetery.
The graveyard probably dates from between the fifth and ninth centuries AD, when the area was occupied by Saxons and Vikings.
The orientation of the burials, running south-west to north-east, suggests they belong to a non-Christian community.
It has emerged the first remains were discovered two weeks ago, although the announcement of the find was delayed until the extent of the cemetery was established.
Doncaster Council, the Archaeological Research and Consultancy at the University of Sheffield, and South Yorkshire Archaeological Services are now working together to investigate the find.
If the current age estimates prove to be correct, it will be the first cemetery of the period excavated in the whole of South Yorkshire.
ARCUS project manager Richard O'Neill, who is leading the six-person team at the site, said: "This is tremendously exciting - this could be the first Anglo-Saxon burial site found in South Yorkshire.
"Apart from the bodies we have found a lot of artefacts. There has been some pottery. Our range of possible dates is at the moment pretty broad but until we carbon-date the remains we can't really be any more specific."
Construction of the new school is continuing, though the area of the archaeological dig has been cordoned off.
Richard said: "Work is continuing on the school as we dig - we're not actually in the way at the moment!"
Doncaster's Mayor Martin Winter said: "I am delighted to hear that one of our schools is at the heart of such an impressive archaeological find. This is a real coup for Doncaster and a welcome addition to the borough's rich archaeological heritage."
Black Death targeted the weak
By Roger Highfield, Science Editor
Last Updated: 10:01pm GMT 28/01/2008
The Black Death, which killed one person in every three in Europe, was not as indiscriminate as thought, according to studies of remains in mass grave in East Smithfield.
The toll was so high during its height in the 1300s that many have concluded that anyone and everyone who came into contact with the agent, thought to be a bacterium, was doomed.
But research published today shows that people who were physically frail and malnourished before the epidemic were more likely to die from the disease than healthy individuals.
The plague of 1347-1351 is the deadliest known epidemic in history, killing an estimated 75 million people, including more than one-third of the European population. Sharon DeWitte and James Wood of the University of Albany, New York, examined 490 skeletons from the East Smithfield Black Death cemetery in London - one of several dug especially for plague victims - for bone damage or other evidence of weakness during life.
For comparison, they used 291 pre-Black Death skeletons from cemeteries elsewhere during the same era. The scientists estimated the victim's age at their time of death and used a computer model to calculate how strongly skeletal damage, associated with natural physical "frailty," were linked to risk of death.
The link between lesions and death was much stronger in the controls than in the London cemetery, showing how even healthy people were killed by the Black Death. However, the study in the Proceedings of the National Academy of Sciences concludes that even in London, frailty - probably the result of poor nutrition - and plague death were linked to some degree.
"This actually contradicts what many have assumed about the epidemic - that given the extraordinary mortality of the Black Death, it must have killed people indiscriminately," says Dr DeWitte. "Some contemporary reports of the Black Death state that everyone was at equal risk. But we have quantitative evidence that not everyone was at the same risk."
"The pattern we observed, of the Black Death targeting the weak but also killing people who were otherwise healthy, is consistent with an emerging disease striking a population with no immunity to that disease," she says.
The plague reached London in the mid 1300s. A new Smithfield cemetery was hurriedly opened by the Bishop of London, but became so swamped that a local landowner, Sir Walter Manny, donated land nearby at Spittle Croft for a second cemetery. Excavation of the East Smithfield cemeteries, revealed that the dead were stacked five deep in the mass graves.
Most believe the Black Death was bubonic plague spread by rats and their fleas but other scholars claim it was an Ebola-like virus transmitted directly from person to person.
UN vandals spray graffiti on Sahara’s prehistoric art
Dalya Alberge, Arts Correspondent
Spectacular prehistoric depictions of animal and human figures created up to 6,000 years ago on Western Saharan rocks have been vandalised by United Nations peacekeepers, The Times has learnt.
Archaeological sites boasting ancient paintings and engravings of giraffes, buffalo and elephants have been defaced within the past two years by personnel attached to the UN mission, known by its French acronym, Minurso.
Graffiti, some of it more than a metre high and sprayed with paint meant for use for marking routes, now blights the rock art at Lajuad, an isolated site known as Devil Mountain, which is regarded by the local Sahrawi population as a mystical place of great cultural significance.
Many of the UN “graffiti artists” signed and dated their work, revealing their identities and where they are from. Minurso personnel stationed in Western Sahara come from almost 30 countries. They are monitoring a ceasefire between the occupying Moroccan forces and the Polisario Front, which is seeking independence.
One Croatian peacekeeper scrawled “Petar CroArmy” across a rock face. Extensive traces of pigment from rock painting are visible underneath. Another left behind Cyrillic graffiti, and “Evgeny” from Russia scribbled AUI, the code for the Minurso base at Aguanit. “Mahmoud” from Egypt left his mark at Rekeiz Lemgasem, and “Ibrahim” wrote his name and number over a prehistoric painting of a giraffe. “Issa”, a Kenyan major who signed his name and wrote the date, had just completed a UN course, Ethics in Peacekeeping, documents show.
Julian J. Harston, the UN’s representative of the Secretary-General for Western Sahara and head of Minurso, said that he had been shocked by the scale of the vandalism. After visiting two of the sites, including Devil Mountain, this week, he said: “I was appalled. You’d think some of them would know better. These are officers, not squaddies.” The UN would take action against any officers “kind enough to leave their calling card. We will report it to the troop-contributing countries. We can move them.”
The extent of the damage is revealed in a report by Nick Brooks, of the University of East Anglia, and Joaquim Soler, of the University of Gerona, Spain, which was passed to The Times yesterday. It outlines the “severe vandalism”, saying that it “now appears to be an essentially universal practice when Minurso staff visit rock art sites . . . Minurso staff have felt entitled to destroy elements of Western Sahara’s and the Sahrawis’ cultural heritage, despite being aware of UN ethics in peacekeeping, and in breach of legislation enshrined in the 1954 Convention for the Protection of Cultural Property in the Event of Armed Conflict.”
It concludes: “Minurso personnel have played a major role in damaging archaeological sites, and such staff are engaged in the systematic defacement of valuable archaeological sites over a large area . . . the recent damage at Lajuad is unprecedented.”
The vandalism will reignite the debate about the conduct of UN peacekeepers after a series of scandals. Last January the UN admitted that more than 200 of its troops had been disciplined for sex offences, including rape and child abuse, in the preceding three years; in May it emerged that Paki-stani peacekeepers had been trading weapons with Congolese militia.