Thomas Jefferson's African Roots
Not only does Thomas Jefferson have African-American descendants- he also had African ancestors.
People of African origin have lived in Britain for centuries, according to genetic evidence.
A Leicester University study found that seven men with a rare Yorkshire surname carry a genetic signature previously found only in people of African origin.
The men seem to have shared a common ancestor in the 18th Century, but the African DNA lineage they carry may have reached Britain centuries earlier.
Details of the study appear in the European Journal of Human Genetics.
The scientists declined to disclose the men's surname in order to protect their anonymity.
The discovery came out of genetic work looking at the relationship between the male, or Y, chromosome and surnames.
The Y chromosome is a package of genetic material normally found only in males.
It is passed down from father to son, more or less unchanged, just like a surname.
Rare lineage
But over time, the Y chromosome accumulates small changes in its DNA sequence, allowing scientists to study the relationships between different male lineages.
Y chromosomes can be classified into different groups (called haplogroups) which, to some extent, reflect a person's geographical ancestry.
Certain haplogroups might be very common in, for example, East Asia and very rare in Europe.
By chance, the researchers discovered a white man with a rare Yorkshire surname carrying a Y chromosome haplogroup that had previously been found only in West African men. And even there, it is relatively uncommon.
"We found that he was in haplogroup A1, which is highly West African-specific," said Turi King, a co-author on the study at the University of Leicester.
"It is incredibly rare, there are only 25 other people known worldwide and they are all African."
Family tree
The individual had no knowledge of any African heritage in his family.
Sharing a surname also significantly raised the likelihood of sharing the same type of Y chromosome, with the link getting stronger as the surname gets rarer. So the researchers started recruiting people with the same last name, which starts with "R" and originates in Yorkshire.
Of 18 people they tested, seven carried the rare African haplogroup.
Turi King and Leicester colleague Mark Jobling then commissioned a genealogist to fit the men into a family tree to see how they were related and find clues about where exactly their unusual Y haplogroup came from.
"He could only get them into two trees, one which dates back to 1788 and the other to 1789. He couldn't go back any further. So it's likely they join up in the early 18th Century," said Turi King.
The majority of the one million people who define themselves as "black" or "black British" trace their origins to immigration from the Caribbean or Africa from the middle of the 20th Century onwards.
Prior to the 20th Century, there have been various routes by which people of African ancestry might have reached Britain. For example, the Romans recruited from Africa and elsewhere for the garrison that guarded Hadrian's Wall.
Different routes
Another major route was through the slave trade.
"Some of the Africans who arrived in Britain through the slave trade rose quite high up in society, and we know they married with the rest of the population," said Ms King.
"It could be either of these two routes," she said. Even if the two family trees link up in the 18th Century, haplogroup A1 could have reached Britain long before that.
"But my guess is that, because many slaves came from West Africa, it could have been through that route," Ms King told BBC News.
She added that the study showed that Britain has always been composed of a mosaic of different people.
Professor Jobling echoed this view: "This study shows that what it means to be British is complicated and always has been," he said.
"Human migration history is clearly very complex, particularly for an island nation such as ours, and this study further debunks the idea that there are simple and distinct populations or 'races'."
Turi King said she had since found another African Y chromosome haplogroup in a different British lineage.
There are other precedents for the finding. When scientists analysed the DNA of the third US president, Thomas Jefferson, they found that his Y chromosome belonged to a haplogroup known as K2.
Jefferson's father claimed Welsh ancestry. But his Y-haplogroup is rare in Europe and has not yet been reported in Britain.
In fact, genetic studies show that Thomas Jefferson's K2 haplogroup ultimately came from north-east Africa or the Middle East, the areas where it is most commonly found today.
People of African origin have lived in Britain for centuries, according to genetic evidence.
A Leicester University study found that seven men with a rare Yorkshire surname carry a genetic signature previously found only in people of African origin.
The men seem to have shared a common ancestor in the 18th Century, but the African DNA lineage they carry may have reached Britain centuries earlier.
Details of the study appear in the European Journal of Human Genetics.
The scientists declined to disclose the men's surname in order to protect their anonymity.
The discovery came out of genetic work looking at the relationship between the male, or Y, chromosome and surnames.
The Y chromosome is a package of genetic material normally found only in males.
It is passed down from father to son, more or less unchanged, just like a surname.
Rare lineage
But over time, the Y chromosome accumulates small changes in its DNA sequence, allowing scientists to study the relationships between different male lineages.
Y chromosomes can be classified into different groups (called haplogroups) which, to some extent, reflect a person's geographical ancestry.
Certain haplogroups might be very common in, for example, East Asia and very rare in Europe.
By chance, the researchers discovered a white man with a rare Yorkshire surname carrying a Y chromosome haplogroup that had previously been found only in West African men. And even there, it is relatively uncommon.
"We found that he was in haplogroup A1, which is highly West African-specific," said Turi King, a co-author on the study at the University of Leicester.
"It is incredibly rare, there are only 25 other people known worldwide and they are all African."
Family tree
The individual had no knowledge of any African heritage in his family.
Sharing a surname also significantly raised the likelihood of sharing the same type of Y chromosome, with the link getting stronger as the surname gets rarer. So the researchers started recruiting people with the same last name, which starts with "R" and originates in Yorkshire.
Of 18 people they tested, seven carried the rare African haplogroup.
Turi King and Leicester colleague Mark Jobling then commissioned a genealogist to fit the men into a family tree to see how they were related and find clues about where exactly their unusual Y haplogroup came from.
"He could only get them into two trees, one which dates back to 1788 and the other to 1789. He couldn't go back any further. So it's likely they join up in the early 18th Century," said Turi King.
The majority of the one million people who define themselves as "black" or "black British" trace their origins to immigration from the Caribbean or Africa from the middle of the 20th Century onwards.
Prior to the 20th Century, there have been various routes by which people of African ancestry might have reached Britain. For example, the Romans recruited from Africa and elsewhere for the garrison that guarded Hadrian's Wall.
Different routes
Another major route was through the slave trade.
"Some of the Africans who arrived in Britain through the slave trade rose quite high up in society, and we know they married with the rest of the population," said Ms King.
"It could be either of these two routes," she said. Even if the two family trees link up in the 18th Century, haplogroup A1 could have reached Britain long before that.
"But my guess is that, because many slaves came from West Africa, it could have been through that route," Ms King told BBC News.
She added that the study showed that Britain has always been composed of a mosaic of different people.
Professor Jobling echoed this view: "This study shows that what it means to be British is complicated and always has been," he said.
"Human migration history is clearly very complex, particularly for an island nation such as ours, and this study further debunks the idea that there are simple and distinct populations or 'races'."
Turi King said she had since found another African Y chromosome haplogroup in a different British lineage.
There are other precedents for the finding. When scientists analysed the DNA of the third US president, Thomas Jefferson, they found that his Y chromosome belonged to a haplogroup known as K2.
Jefferson's father claimed Welsh ancestry. But his Y-haplogroup is rare in Europe and has not yet been reported in Britain.
In fact, genetic studies show that Thomas Jefferson's K2 haplogroup ultimately came from north-east Africa or the Middle East, the areas where it is most commonly found today.
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DNA testing carried out by University of Leicester geneticists and funded by The Wellcome Trust has thrown new light on the ancestry of one of the USA’s most revered figures, the third President, Thomas Jefferson.
Almost 10 years ago, the University of Leicester team, led by Professor Mark Jobling, together with international collaborators, showed that Thomas Jefferson had fathered at least one of the sons of Sally Hemings, a slave of Jefferson’s.
The work was done using the Y chromosome, a male-specific part of our DNA that passes down from father to son. Jefferson carried a very unusual Y chromosome type, which helped to strengthen the evidence in the historical paternity case.
Now, new techniques have been brought to bear on Jefferson’s Y chromosome, in a study reported in the American Journal of Physical Anthropology. The presidential chromosome turns out to belong to a rare class called ‘K2’, which is found at its highest frequency in the Middle East and Eastern Africa, including Oman, Somalia and Iraq. Its closest match was in a man from Egypt. Could this mean that the President had recent ancestry in the Middle East? A careful survey revealed a few K2 chromosomes in France, Spain and England. Together, the K2s form a diverse group that may, in fact, have been in western Europe for many thousands of years.
Further evidence for Jefferson’s British origins come from the finding that two out of 85 randomly recruited men named Jefferson share exactly the same Y chromosome as the President. Prof Jobling said: ‘The two men have ancestry in Yorkshire and the West Midlands, and knew of no historical connection to the USA. They were amazed and fascinated by the link, which connects them into Thomas Jefferson’s family tree, probably about 11 generations ago.’
The ultimate origins of K2 chromosomes remain a mystery, however, and need further investigation: while they may have been present in Europe since the Stone Age, another possibility is that K2s came to Europe with the Phoenicians, an ancient maritime trading culture that spread out across the Mediterranean from their home in what is now Lebanon. The US media has taken up a different theory, leading to the New York Times headline, ‘Jefferson – the first Jewish president?’: European K2 chromosomes may originate in Sephardic (Spanish) Jewish populations, who have their ultimate origins in the Middle East.
Prof Jobling said: ‘When we look closely at large collections of British Y chromosomes we find surprises, like this rare K2 lineage, and the African chromosome that we recently found in a Yorkshireman. These exotic chromosomes remind us of the complexity of British history and prehistory.’