Thursday, 28 February 2008

The first DNA success story

The DNA project is going better than I ever expected. Although it has only been running for around five months I already have nineteen participants – most projects are considered to be doing well if they manage to attract one participant a month! I am very grateful to everyone who has agreed to take part and in particular I would like to thank Pieter Cruse who has made a very generous donation which has been used to pay for three test kits.

The first big success story from the project is that it has been possible to validate the paper research and identify the genetic signature of the key Cruwys Morchard line from Devon. The male line at Cruwys Morchard died out in 1804 with the death of Henry Shortrudge Cruwys, the then Lord of the Manor. He was succeeded by his daughter, Harriet, who had married George Sharland in 1794. Their son George Sharland succeeded to the Cruwys Morchard estate and in 1831 changed his name to Cruwys by royal licence, and was thenceforth known as George Sharland Cruwys. Because the Y-DNA used for genealogical testing is passed directly from father to son, a Y-DNA test on a descendant from this line would therefore give us the genetic signature of the Sharlands, and would tell us nothing about the Cruwys Y-DNA.

Fortunately however it has been possible to identify other likely descendants of the Cruwys Morchard line. One person who is descended from the Winkleigh Cruwys line has now taken the test along with another tester who is descended from the Cornish Crewes line. These two men are believed to share a common ancestor in John Cruwys of Cruwys Morchard, who was born about 1449. John was the son of Sir Thomas Cruwys, who died at, or shortly after, the Battle of Tewkesbury in 1471, leaving his then 22-year-old son as his heir. The Winkleigh line is thought to be descended from Thomas Cruwys, the great-grandson of John Cruwys and his first wife Elizabeth Whitley. Thomas was the second son of John Cruwys of Cruwys Morchard and Anne Keynes of Winkleigh. He was buried in Winkleigh in 1596. The Cornish Crewes line has been meticulously researched by Tom Johns, now sadly deceased. His research was published in 2001 in a booklet entitled "Crewes of South Cornwall, and their ancestors in Liskeard, Cornwall and Cruwys Morchard, Devon". Tom has been able to prove through wills, inquisitions post mortem, parish registers and other documents that the Cornish Crewes line are descended from Anthony Cruwys/Crewes the son of John Cruwys of Cruwys Morchard by his second marriage to Mary Fraunceys. Anthony moved from Cruwys Morchard to Liskeard in Cornwall where he married Joanna Bealbury, the eldest daughter of a wealthy merchant, John Bealbury. The Cornish line have their own coat of arms and have consistently used the Crewes spelling.

By getting a descendant from each of these two lines to take the Y-DNA test it was hoped that the two results would be sufficiently close to prove that the two men do indeed share a common male ancestor. Needless to say, not everything went according to plan. When the 12-marker results for the Cornish Crewes tester came through in mid January, there was only a match on 10 of the 12 markers. In addition there was a two-step difference on one of the markers, giving a genetic difference of three. According to the Family Tree DNA calculator, based on these results, there was only an 18.14% probability that the two men shared a common ancestor within the last sixteen generations. The results were not at all promising and I had convinced myself to expect the worst when the 25- and 37-marker results came through. We then had an agonisingly long wait as the lab was unable to get definitive results and had to re-run the test three times before the result was finally made available this week. The 25- and 37-marker results both came through on the same day and to my astonishment the two testers matched on every single one of the remaining markers. The 10/12 match had been transformed into a 35/37 match. The FTDNA calculator now predicted that the probability of the two men sharing a common ancestor within the last 16 generations was 97.49%! Finally I had the result that I wanted but hadn't dared to expect.

I have since learnt that this apparent 10/12 mismatch is what is known as a false negative. It demonstrates the importance of testing the maximum number of markers. Other project administrators have reported similar cases, and a good example can be found in the Kerchner surname project.

The other DNA results can be seen on the project website. It has now been possible to allocate people into specific genetic groups based on their DNA results, though it is too early to draw too many conclusions at this stage. A number of results are still awaited, and some kits have only just been sent out in the post. There are some potentially interesting tests in the pipeline and I hope to be able to report on some more exciting results in the near future.

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