DNA secrets from Anglo-Saxon burial site

Recent building works in Oakington, near Cambridge, have uncovered an Anglo Saxon burial site. With the help of DNA experts in Australia, archaeologists have used the human remains recovered from the site to build an Anglo Saxon genetic profile that they've been able to compare with modern Britons. This is revealing how these European immigrants - a thousand years ago - mixed with the general population. Graihagh Jackson went to meet archaeologist Richard Mortimer at the Museum of Archaeology and Anthropology to see what the research has been turning up...

Richard - The Anglo Saxons are the formation of England as we now know it.  Because by the end of the early Anglo Saxon period, by about  700 AD, England has become physically what it looks like today in the fact that all of our villages and most of our towns is formed or is forming by about 700.

Graihagh - There's a collection of about 20 objects here.  They all look like gold but I'm sure they're probably not.  People would have been buried with these things - talk me through, what are these?

Richard - Well they are gold, they're gold gilt. Bronze underneath and then gold gilt on top and they are, quite frankly, one of the most beautiful things you'll ever find, as an archeologist.  These on the right, these large ones, they'd be for ladies to wear and they'd be to hold, with a pin, hold your dress together.

Graihagh - They're brooches then?  They actually are massive.  Some of them are bigger than my hand; they almost look like door knockers, to be honest.

Richard - Yes they do.  I can't deny it.

Graihagh - And I can see necklaces and combs.  They look like little keys on keyrings but I assume they're not that.

Richard -   Yes, they are, they're girdle hangers - formalised key sets.  One of the women at Oakington buried, oddly enough with a cow; that's not only unusual, it's a first in Britain, it's a first in Anglo Saxon Europe. Nobody's ever been buried with a cow before.  And she, the cow lady, got the keys to every lock, and every latch, and every box in that settlement.

Graihagh - Why on earth would you be buried with a cow?

Richard - Absolutely no idea whatsoever.  Because it's a first, you just have try and make up our own reasons, you know.  Archaeologists just do it anyway.  We're telling stories half the time, not telling truths.

Graihagh - Women buried with cows and made up stories aside, this site is extremely important in our quest to understand our British heritage.  Over a hundred people were buried at Oakington and they were in good enough condition for scientists, like Dr Richard Durbin, to extract DNA and find out just how Anglo Saxon we really are.

Richard - So what we do is we take a bone, in fact, in our case we took the teeth which are kind of protected by the enamel.  We sent those to an expert laboratory in South Australia where they purified, removed all the DNA from the outside so as to get rid of any contaminated material, and then ground it up and isolated a very small amount of DNA and, very sensitively, we brought that back and because it's been degraded, it's in small pieces.  So technically this is a hard thing to do but it's become feasible over the last five years or so, and there have been a number of studies but this is the first study of British samples from more than a thousand years ago.

Graihagh - And what, you compared that data with modern humans?

Richard - Yes, what we did is we looked at some of those places where there were clear differences, which were rare and recent, which could tell us a lot about where people came from and then we looked in the ancient samples to see who they shared most with and where they fell in that spectrum of modern variation.

Graihagh - And so, how Anglo Saxon are we?

Richard - Well.  It turns out that modern English are about, in the east of England, are about 38%, but if we go further west, Cornwall or to Wales, that fraction drops.  So we're all a mixture of the people who were here before, and the people who came in the Dark Ages.

Graihagh - But why is it that modern Welsh are only 30% Anglo Saxon versus east of England being 38% Anglo Saxon?

Richard - I would presume that that is because people coming into the country, you know, predominantly settle in the east, and only progressively moved further afield into the west of England.

Graihagh - So it sort of matches the migration pattern.  The Anglo Saxons came over from Europe and landed in the east of England and then migrated west and north, and that's why you see less of this genetic influence on the Scottish, and the Welsh, and people from Cornwall.

Richard - Yes.

Graihagh - It's said quite often, you share, what 50% of your genes with a banana and within species, the human race, it's something like 99.9% or whatever it is.  So surely, given that Europeans and these local inhabitants from the Iron Age would have shared a lot of their DNA, what sort of mutations were you looking for to distinguish these populations.

Richard -    We're all North West Europeans; we're all genetically quite similar to each other so the differences are subtle.  Although we only differ from each other one in a thousand places across three billion bases, that amounts to several million differences.  Sometimes new mutations happen, that's what gives rise to differences and ones that happen within a country, within say Denmark, will only be found in the Danes, or in people who mate with them. So we were looking for those, very rare, mutations as traces of identity.

Graihagh - And you say us in the East are 38% Anglo Saxon, often you hear you're 2% Neanderthal!  So what's the remaining 60% of us?

Richard - Modern humans left Africa about 50 000 years ago, and that point they met other human species and Neanderthals who had left several hundred thousand years ago, and there was a little bit of intermixing at this point which contributed about 2% we think. And then in Europe there were the hunter gatherer peoples who did the cave paintings that one finds in France and Spain. And then after the ice age the farmers came in and moved across Europe from Turkey, and then there was a later movement of peoples bringing metalworking from Russia. So all of these things have left genetic traces we know other people have been studying. We know people from Britain are a mix of all of those.

Graihagh - An area of further research then?

Richard - I think this is just beginning now, alongside the medical advances we obtained from understanding how the genome works in the body, it will tell us about our history as people and evolution. It's a very exciting time to be a genome scientist.