|This article relies on references to primary sources. (May 2010)|
||The examples and perspective in this article may not include all significant viewpoints. (May 2010)|
Sykes published the first report on retrieving DNA from ancient bone (Nature, 1989). Sykes has been involved in a number of high-profile cases dealing with ancient DNA, including those of Ötzi the Iceman and Cheddar Man, and others concerning people claiming to be members of the Romanovs, the Russian royal family. His work also suggested a Florida accountant by the name of Tom Robinson was a direct descendant of Genghis Khan, a claim that was subsequently disputed.   
Sykes is best known outside the community of geneticists for his bestselling books on the investigation of human history and prehistory through studies of mitochondrial DNA. He is also the founder of Oxford Ancestors, a genealogical DNA testing firm.
Blood of the Isles 
In his 2006 book Blood of the Isles (published in the United States and Canada as Saxons, Vikings and Celts: The Genetic Roots of Britain and Ireland), Sykes examines British genetic "clans". He presents evidence from mitochondrial DNA, inherited by both sexes from their mothers, and the Y chromosome, inherited by men from their fathers, for the following points:
- The genetic makeup of Britain and Ireland is overwhelmingly what it has been since the Neolithic period and to a very considerable extent since the Mesolithic period, especially in the female line, i.e. those people, who in time would become identified as British Celts (culturally speaking), but who (genetically speaking) should more properly be called Cro-Magnon. In continental Europe, this same Cro-Magnon genetic legacy gave rise to the Basques. But "Basque" and "Celt" are cultural designations, not genetic ones.
- The contribution of the Celts of central Europe to the genetic makeup of Britain and Ireland was minimal; most of the genetic contribution to the British Isles of those we think of as Celtic, came from western continental Europe, I.E. the Atlantic seaboard.
- The Picts were not a separate people: the genetic makeup of the formerly Pictish areas of Scotland shows no significant differences from the general profile of the rest of Britain. The two "Pictland" regions are Tayside and Grampian.
- The Anglo-Saxons are supposed, by some, to have made a substantial contribution to the genetic makeup of England, but in Sykes's opinion it was under 20 percent of the total, even in southern England.
- The Vikings (Danes and Norwegians) also made a substantial contribution, which is concentrated in central, northern, and eastern England - the territories of the ancient Danelaw. There is a very heavy Viking contribution in the Orkney and Shetland Islands, in the vicinity of 40 percent. Women as well as men contributed substantially in all these areas, showing that the Vikings engaged in large-scale settlement.
- The Norman contribution was extremely small, on the order of 2 percent.
- In spite of all these later contributions, the genetic makeup of the British Isles remains overwhelmingly what it was in the Neolithic: a mixture of the first Mesolithic inhabitants with Neolithic settlers who came by sea from Iberia and ultimately from the eastern Mediterranean.
- There is a difference between the genetic histories of men and women in Britain and Ireland. The matrilineages show a mixture of original Mesolithic inhabitants and later Neolithic arrivals from Iberia, whereas the patrilineages are much more strongly correlated with Iberia. This suggests (though Sykes does not emphasize this point) replacement of much of the original male population by new arrivals with a more powerful social organization.
- There is evidence for a "Genghis Khan effect", whereby some male lineages in ancient times were much more successful than others in leaving large numbers of descendants; e.g. Niall of the Nine Hostages in 4th and 5th century Ireland and Somerled in 12th century Scotland.
Some quotations from the book follow. (Note that Sykes uses the terms "Celts" and "Picts" to designate the pre-Roman inhabitants of the Isles who spoke Celtic and does not mean the people known as Celts in central Europe.)
[T]he presence of large numbers of Jasmine’s Oceanic clan … says to me that there was a very large-scale movement along the Atlantic seaboard north from Iberia, beginning as far back as the early Neolithic and perhaps even before that. …The mere presence of Oceanic Jasmines indicates that this was most definitely a family based settlement rather that the sort of male-led invasions of later millennia.
The Celts of Ireland and the Western Isles are not, as far as I can see from the genetic evidence, related to the Celts who spread south and east to Italy, Greece and Turkey from the heartlands of Hallstadt and La Tene...during the first millennium BC…The genetic evidence shows that a large proportion of Irish Celts, on both the male and female side, did arrive from Iberia at or about the same time as farming reached the Isles. (…)
The connection to Spain is also there in the myth of Brutus…. This too may be the faint echo of the same origin myth as the Milesian Irish and the connection to Iberia is almost as strong in the British regions as it is in Ireland. (…)
Here again, the strongest signal is a Celtic one, in the form of the clan of Oisin, which dominates the scene all over the Isles. The predominance in every part of the Isles of the Atlantis chromosome (the most frequent in the Oisin clan), with its strong affinities to Iberia, along with other matches and the evidence from the maternal side convinces me that it is from this direction that we must look for the origin of Oisin and the great majority of our Y-chromosomes…I can find no evidence at all of a large-scale arrival from the heartland of the Celts of central Europe amongst the paternic genetic ancestry of the Isles… can
Japanese clans 
Books by Bryan Sykes 
- Sykes, Bryan (1999), The Human Inheritance: Genes, Language, and Evolution, Oxford University Press, ISBN 0-19-850274-5
- Sykes, Bryan (2002), The Seven Daughters of Eve, Corgi, ISBN 0-552-14876-8
- Sykes, Bryan (2003), Adam's Curse: A Future Without Men, Bantam, ISBN 0-593-05004-5
- Sykes, Bryan (2006), Blood of the Isles: Exploring the Genetic Roots of Our Tribal History, Bantam, ISBN 0-593-05652-3
- Sykes, Bryan (2011), DNA USA: A Genetic Biography of America, W. W. Norton & Company, ISBN 978-0-393-07804-6
See also 
- Tom Robinson (June 16, 2006), Genghis Khan or Not? That is the Question (Internet Archive version)., Self published, retrieved 2013-31-01
- Matching Genghis Khan, familytreedna.com, retrieved 2008-06-03[dead link]
- Henderson, Mark (May 30, 2006), How I am related to Genghis Khan, London: The Times, retrieved 2010-04-27
- Nicholas Wade. Falling from Genghis's family tree New York Times, 21 June 2006. Accessed 31 January 2013.
- Sykes 2006, pp. 280–281
- Sykes 2006, pp. 281–282
- Sykes 2006, pp. 283–284
- Japanese women seek their ancestral roots in Oxford by Tessa Holland, 25 June 2006, Kyodo News