WASHINGTON (Reuters) - Curious about your noble forebears?  Eager to see if you are related to someone else with the same  last name? An Oxford genetics professor can answer your  questions.
    Brian Sykes, an expert in genetics at Britain's Oxford  University, said on Tuesday he had checked the DNA of dozens of  men who had the same surname and found, to his surprise, that  they all seem to have descended from the same ancestor.  Examining men with the same surname as his own, Sykes used a  technique known as genetic fingerprinting to examine the men's Y  chromosome, which is handed down with very little change from  father to son.
    "I wrote 250 men, a random sample, with the same surname  and I wrote to Sykeses because I felt confident approaching  people with the same name as mine," Sykes said in a telephone  interview.  He tracked the men down in three English counties known to  have many people with the Sykes name -- York, Cheshire and  Lancashire. He sent them home DNA kits that included a brush to  take a few cells from the inside of the mouth.
    "I got 61 returns of DNA on little brushes and of those,  half had a Y chromosome microsatellite fingerprint which showed  they had exactly the same Y chromosome," Sykes said.  Microsatellites are little repeated sequences of the four  nucleotides -- A, C, T and G -- that seem to carry no important  genetic instructions but which can be used as "fingerprints"  to identify genes.  Sykes, who reported his findings in the American Journal of  Human Genetics, said he was surprised to find the same  fingerprint in so many different men who had no idea they were  related.
    "The only explanation is all Sykeses had come from a single  male who first inherited that name," he said. "We reckon from  the court records the name first appears in West Yorkshire in  just about 1300."
    Before then, most English peasants went by just one name or  had names they did not pass on to their children.   "Surnames became inherited because it was a time you were  able to transfer the tenancy of your land to your children,"  Sykes said.
    He had not expected such a pedigree for his name, in  particular, which seems to have had few noble associations.   "Sykeses were all peasants and vagabonds," he laughed.  "They were always cropping in the court records as having  stolen sheep or burnt woods down."  He said the name means a small stream and he would have  thought many people would have taken such a name.

    There was another eye opener in his findings.  "With 50 percent having the same Y chromosome ... it works  out roughly at about 1 percent per generation for no  paternity," Sykes said.
    "It's really quite low -- lower than the rates we are  accustomed to these days. It essentially means that 99 percent  of Mrs. Sykeses have been very well-behaved."  Sykes, whose lab linked a 9,000-year-old skeleton known as  "Cheddar Man" to an Englishman living nearby in 1997, said the  applications of this latest work will be most valuable to people  tracing family histories.
    "It is astounding news for genealogists," he said.  Noting that written records are rare before 1700, he said it  would be a good way for people to track their ancestry.  Anticipating this, he has patented the test for an  association between a surname and the Y chromosome, and, with  the university, started up a company to perform the tests.  "We are probably going to call it Oxford Ancestors," he  said.