Prisoner Of Ice
03-04-2015, 04:55 PM
http://news.bbc.co.uk/2/hi/science/nature/6293333.stm
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.
Portrait of Thomas Jefferson by the artist Rembrandt Peale Image: AP
Analysis of Thomas Jefferson's DNA also threw up a surprise
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.
I'm actually surprised you don't find random 'wrong' clades much more often.
Of course for all we know this is neanderthal y-dna anyhow. For A00 y-dna most the samples were actually found in france. I won't be surprised they turn out to all be white guys with no known african ancestry.
But I'd also not be surprised if it just floated around as a leftover for eons with no real link to africa at all.
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.
Portrait of Thomas Jefferson by the artist Rembrandt Peale Image: AP
Analysis of Thomas Jefferson's DNA also threw up a surprise
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.
I'm actually surprised you don't find random 'wrong' clades much more often.
Of course for all we know this is neanderthal y-dna anyhow. For A00 y-dna most the samples were actually found in france. I won't be surprised they turn out to all be white guys with no known african ancestry.
But I'd also not be surprised if it just floated around as a leftover for eons with no real link to africa at all.