Beorn
09-22-2009, 04:08 PM
http://www.timesonline.co.uk/multimedia/archive/00553/dna_553759a.jpg
Interest in our ancestors has surged in recent years, thanks largely to the internet. The latest development is commercial DNA testing, which can reveal the possible migrations of a person’s distant ancestors or help to solve more recent genealogical problems.
The tests are painless, requiring a cheek swab. However, the science behind them is young, prices can be high and the results, as Times Money discovered, can be contradictory. Here we explore the market.
Why Y?
Several companies offer tests of men’s Y chromosomes — a piece of DNA that is passed down the male line and mutates slowly. Results give numerical values for a series of “markers”. The more closely these values match for two men, the more closely they are likely to be related in that line. Scientists have divided Y chromosomes into numerous “haplogroups”, or clans, each descended in the male line from a single ancestor who lived thousands of years ago. These can be linked in a family tree descended from the common male-line ancestor of all humans who lived in northeast Africa about 60,000 to 90,000 years ago.
Haplogroups can be subdivided into smaller, common-ancestor lineages. For instance, there is a Y chromosome signature characteristic of Jewish Cohens — the priestly caste said to descend from Aaron, the brother of Moses. Another is thought to indicate descent from Genghis Khan.
Ancient origins
The Genographic Project, a non-profit collaboration between IBM and National Geographic, offers a $100 (£60) test to determine a participant’s haplogroup. Results are accessed on the internet and explained in online videos and presentations.
The price subsidises DNA testing of indigenous peoples across the world for scientific study — including work for a forthcoming paper on the origins of the Tibetans.
A Genographic test indicates that I belong to haplogroup R1b, the most common in Western Europe. According to the project material, my ancestors moved from Africa, through Arabia into Central Asia and from there pushed westwards into Europe — spending the last Ice Age in a “refugium” in southern Spain before moving north, starting 12,000 years ago. Spencer Wells, the project scientist, says that it is difficult to track migrations after this because matches are found so widely.
Nevertheless, several providers offer tests with analysis of when the first male-line ancestor of customers with British ancestry is likely to have arrived on these shores. The best-known of these companies is Oxford Ancestors, founded by Bryan Sykes, Professor of Human Genetics at the University of Oxford. Customers pay £180 for a Y chromosome test of 15 markers (against 12 markers at the Genographic Project) and assignment to a haplogroup.
An extra £10 buys Tribes of Britain analysis to determine “Celtic, Saxon or Viking” ancestry. After tests that matched the Genographic Project’s on the common markers tested, the company designated my Y chromosome as most likely “Celtic”. Meanwhile, Andrew Ellson, the Times Money editor, was in haplogroup I and most likely “Anglo-Saxon”.
However, James Wilson, of the University of Edinburgh, a geneticist and founder of EthnoAncestry, another test company, disagrees. He says that Ellson’s Y chromosome is “almost certainly” indigenous British, of a rare type brought to Britain by the first post-Ice Age settlers. He adds that mine is harder to call, but of a type that came from Germany, both before the Roman conquest and with the Anglo-Saxons. EthnoAncestry offers a 27-marker Y Chromosome test for $269 (£165) and assigns customers to numerous sub-groups within haplogroups — identifying “Pictish” and “Germanic” as well as indigenous lineages of R1b, for example.
Mark Jobling, of the University of Leicester, another geneticist who has used the Y chromosome to study the histories of populations in Western Europe, says that EthnoAncestry’s work is “interesting”, but that it is too early to make meaningful conclusions about the arrival histories in Britain of most lineages.
Surnames and families
Professor Jobling adds that Y chromosome tests can more safely be used to investigate genealogical relationships — suggesting whether, or how closely, men who share a rare surname are related, for example.
His research indicates that many rare surnames, including Attenborough, had a single founder and carry a characteristic Y chromosome signature. Many amateur genealogists have started DNA projects for specific surnames to establish whether, and how, the families are related. Most studies use one provider, such as Family Tree DNA, which tests 12 markers for $119 (£72), 37 for $169 (£102) or 67 for $268 (£162), with discounts for bulk orders. The tests can only be used to give probabilities. For example, according to a much used model, there is a 50 per cent chance that two men who match on 25 out of 25 markers tested share a common ancestor within seven generations and a 90 per cent chance that they share a common ancestor within 23 generations.
These sort of odds can be used to back up speculation based on old-fashioned paper-based research — not to conjure up names and dates.
Professor Jobling says that tests of about 25 markers are adequate for most family history purposes. Tests of 12 markers are not, because even an exact match could indicate common descent from a man living as many as 40 generations ago.
Examples of other amateur DNA projects include studies of the surnames Warburton and Sainsbury. The former indicates that several founders took the name in the medieval period.
And for the girls
Mitochondrial DNA, which is passed down the female line, offers an alternative means of studying population movements.
Everyone, male and female, belongs to a mitochondrial haplogroup — a clan descended in the female line from a common ancestor. As with Y chromosome haplogroups, these can be linked in a family tree descending from a common African founder.
Less is known about the histories of the various mitochondrial lineages, hence the focus of this article. However, tests are available from the same providers and in a similar price range.
Analysis: More than a numbers game
Learning about the prehistoric journey of my male-line ancestors out of Africa and into Europe via Central Asia was interesting, but initially I was disappointed that there was no consensus on when they would have arrived in Britain.
Nevertheless, I know from written and oral family history that they moved from Lancashire to central Ireland in the 17th century and stayed there until the 20th century — a part of family identity that tests such as these are bound to miss.
I am also aware that the Y chromosome is a small part of my DNA and that, test or no test, my ancestors in all lines, male and female, more than a numbers game it include native Britons, Angles, Saxons and Vikings, as well as people from many other cultures. It would be a shame to identify with only one of them because of a string of numbers.Source (http://www.timesonline.co.uk/tol/money/consumer_affairs/article6839769.ece)
Good article. Highlighting to readers where they can go to obtain a DNA test and the results they could expect to find, but I'm still wondering why the author thinks the tests would not be able to discern the 300 years his family spent in Ireland.
Interest in our ancestors has surged in recent years, thanks largely to the internet. The latest development is commercial DNA testing, which can reveal the possible migrations of a person’s distant ancestors or help to solve more recent genealogical problems.
The tests are painless, requiring a cheek swab. However, the science behind them is young, prices can be high and the results, as Times Money discovered, can be contradictory. Here we explore the market.
Why Y?
Several companies offer tests of men’s Y chromosomes — a piece of DNA that is passed down the male line and mutates slowly. Results give numerical values for a series of “markers”. The more closely these values match for two men, the more closely they are likely to be related in that line. Scientists have divided Y chromosomes into numerous “haplogroups”, or clans, each descended in the male line from a single ancestor who lived thousands of years ago. These can be linked in a family tree descended from the common male-line ancestor of all humans who lived in northeast Africa about 60,000 to 90,000 years ago.
Haplogroups can be subdivided into smaller, common-ancestor lineages. For instance, there is a Y chromosome signature characteristic of Jewish Cohens — the priestly caste said to descend from Aaron, the brother of Moses. Another is thought to indicate descent from Genghis Khan.
Ancient origins
The Genographic Project, a non-profit collaboration between IBM and National Geographic, offers a $100 (£60) test to determine a participant’s haplogroup. Results are accessed on the internet and explained in online videos and presentations.
The price subsidises DNA testing of indigenous peoples across the world for scientific study — including work for a forthcoming paper on the origins of the Tibetans.
A Genographic test indicates that I belong to haplogroup R1b, the most common in Western Europe. According to the project material, my ancestors moved from Africa, through Arabia into Central Asia and from there pushed westwards into Europe — spending the last Ice Age in a “refugium” in southern Spain before moving north, starting 12,000 years ago. Spencer Wells, the project scientist, says that it is difficult to track migrations after this because matches are found so widely.
Nevertheless, several providers offer tests with analysis of when the first male-line ancestor of customers with British ancestry is likely to have arrived on these shores. The best-known of these companies is Oxford Ancestors, founded by Bryan Sykes, Professor of Human Genetics at the University of Oxford. Customers pay £180 for a Y chromosome test of 15 markers (against 12 markers at the Genographic Project) and assignment to a haplogroup.
An extra £10 buys Tribes of Britain analysis to determine “Celtic, Saxon or Viking” ancestry. After tests that matched the Genographic Project’s on the common markers tested, the company designated my Y chromosome as most likely “Celtic”. Meanwhile, Andrew Ellson, the Times Money editor, was in haplogroup I and most likely “Anglo-Saxon”.
However, James Wilson, of the University of Edinburgh, a geneticist and founder of EthnoAncestry, another test company, disagrees. He says that Ellson’s Y chromosome is “almost certainly” indigenous British, of a rare type brought to Britain by the first post-Ice Age settlers. He adds that mine is harder to call, but of a type that came from Germany, both before the Roman conquest and with the Anglo-Saxons. EthnoAncestry offers a 27-marker Y Chromosome test for $269 (£165) and assigns customers to numerous sub-groups within haplogroups — identifying “Pictish” and “Germanic” as well as indigenous lineages of R1b, for example.
Mark Jobling, of the University of Leicester, another geneticist who has used the Y chromosome to study the histories of populations in Western Europe, says that EthnoAncestry’s work is “interesting”, but that it is too early to make meaningful conclusions about the arrival histories in Britain of most lineages.
Surnames and families
Professor Jobling adds that Y chromosome tests can more safely be used to investigate genealogical relationships — suggesting whether, or how closely, men who share a rare surname are related, for example.
His research indicates that many rare surnames, including Attenborough, had a single founder and carry a characteristic Y chromosome signature. Many amateur genealogists have started DNA projects for specific surnames to establish whether, and how, the families are related. Most studies use one provider, such as Family Tree DNA, which tests 12 markers for $119 (£72), 37 for $169 (£102) or 67 for $268 (£162), with discounts for bulk orders. The tests can only be used to give probabilities. For example, according to a much used model, there is a 50 per cent chance that two men who match on 25 out of 25 markers tested share a common ancestor within seven generations and a 90 per cent chance that they share a common ancestor within 23 generations.
These sort of odds can be used to back up speculation based on old-fashioned paper-based research — not to conjure up names and dates.
Professor Jobling says that tests of about 25 markers are adequate for most family history purposes. Tests of 12 markers are not, because even an exact match could indicate common descent from a man living as many as 40 generations ago.
Examples of other amateur DNA projects include studies of the surnames Warburton and Sainsbury. The former indicates that several founders took the name in the medieval period.
And for the girls
Mitochondrial DNA, which is passed down the female line, offers an alternative means of studying population movements.
Everyone, male and female, belongs to a mitochondrial haplogroup — a clan descended in the female line from a common ancestor. As with Y chromosome haplogroups, these can be linked in a family tree descending from a common African founder.
Less is known about the histories of the various mitochondrial lineages, hence the focus of this article. However, tests are available from the same providers and in a similar price range.
Analysis: More than a numbers game
Learning about the prehistoric journey of my male-line ancestors out of Africa and into Europe via Central Asia was interesting, but initially I was disappointed that there was no consensus on when they would have arrived in Britain.
Nevertheless, I know from written and oral family history that they moved from Lancashire to central Ireland in the 17th century and stayed there until the 20th century — a part of family identity that tests such as these are bound to miss.
I am also aware that the Y chromosome is a small part of my DNA and that, test or no test, my ancestors in all lines, male and female, more than a numbers game it include native Britons, Angles, Saxons and Vikings, as well as people from many other cultures. It would be a shame to identify with only one of them because of a string of numbers.Source (http://www.timesonline.co.uk/tol/money/consumer_affairs/article6839769.ece)
Good article. Highlighting to readers where they can go to obtain a DNA test and the results they could expect to find, but I'm still wondering why the author thinks the tests would not be able to discern the 300 years his family spent in Ireland.