June 21, 2006
Falling From Genghis's Family Tree
从成吉思汗的族谱跌出
By NICHOLAS WADE
尼古拉斯•韦德
DNA tests have furnished a double surprise for Thomas R. Robinson, an associate professor of accounting at the University of Miami. The first was being told he was descended from Genghis Khan. The second was learning last week that the first test was wrong.
DNA检测结果让佛罗里达大学的会计学副教授汤姆•罗宾森两次出乎意料。第一次的结果说明他是成吉思汗后裔。第二次的DNA检测显示，第一次的结果是个错误。
Mr. Robinson's own caution was one cause of this vicissitude. His temporary induction into the Mongol royal house began in April, when he received a call from Oxford Ancestors, an English DNA testing company he had asked in 2003 to test his Y chromosome. The company said that on a recent scan of its database Mr. Robinson's chromosome had emerged as having a genetic signature very close to Genghis Khan's.
罗宾森先生自身的小心谨慎是这起变故的一个原因。他暂时加入蒙古皇家族谱要追溯到4月, 当时他收到英国“牛津寻祖”公司来电。2003 年他曾请求这家英国 DNA 测试公司检验他的Y染色体。该公司告知, 最近的一次数据库检验结果显示，罗宾森与成吉思汗的基因特征非常接近。
Mr. Robinson's male ancestors were British. Perhaps because of that apparent incongruity — and the contrast between his profession and Genghis Khan's — the finding was reported in several newspapers, including The New York Times.
罗宾森的父系祖先来自英国。也许因为他的职业和成吉思汗的所作所为有天壤之别，这个发现被《纽约时报》等多家报纸报导。
Then a movie company offered to fly Mr. Robinson out to Mongolia. But instead of sitting back and basking in the posthumous fame of his new ancestor as many people might have done, Mr. Robinson decided to get a second opinion before matters went any further.
接着有一家电影公司愿意资助罗宾森到蒙古一游。但是罗宾森并没有象多数人那样坐享先人的福泽，他决定听听不同意见，以免事情一发不可收拾。
He sought the view of Family Tree DNA of Houston, only to learn last week from its president, Bennett Greenspan, that he belonged to a different branch of the Y chromosome family tree from that of the Mongol emperor, and could not be descended from him.
这次他改委托休斯敦的“族谱DNA”公司进行检测，并在上周得知结果。该公司总裁葛林斯班亲自告诉他，他的Y染色体族谱与成吉思汗属于不同的分支，因此不可能是这位蒙古大帝的后裔。
Chris Tyler-Smith, a geneticist at the Sanger Institute in Cambridge, England, said Family Tree DNA's analysis was correct. The company's test of Mr. Robinson's Y chromosome "conclusively rules out a link to the Genghis Khan haplotype," he wrote in an e-mail message.
英国剑桥桑格研究所的基因学家泰勒史密斯也说，族谱DNA公司的分析应该是正确的。
A team led by Dr. Tyler-Smith identified the haplotype, or genetic signature, of the Mongol royal house in 2003 after a survey showed it to be carried by an estimated 16 million men living in the lands of the former Mongol empire. The domain of Genghis and his heirs stretched from the Caspian Sea to the Pacific Ocean, and Genghis is said by contemporary historians to have labored assiduously in his large harems.
由史密斯泰勒领导的团队在2003年调查发现，在前蒙古帝国内，约有1600万人具有相同的Y染色体单套型（基因特征），由于成吉思汗帝国范围从里海到太平洋，加上他的子孙众多，因此推定出这就是成吉斯汗的基因特征。
Mr. Robinson said that he was disappointed only that Oxford Ancestors had not run the same test as Family Tree DNA had done, or at least told him it was available.
罗宾森说，他很失望牛津寻祖公司没有帮他进行Y染色体单套型鉴定，或是至少该告诉他还有这种鉴定可以利用。
Bryan Sykes, the founder of Oxford Ancestors, said he agreed with Dr. Tyler-Smith's verdict but maintained that his original interpretation was reasonable.
牛津寻祖公司的创办人塞吉斯说，他同意史密斯泰勒的判定结果，但是宣称自己当初的解释并没有不合理之处。
The discrepancy occurred because Oxford Ancestors only tested Mr. Robinson's Y chromosome at nine sites, ones at which the DNA mutates quite often between generations. Finding a match between Mr. Robinson and Genghis at seven of nine sites, Dr. Sykes assumed that was good enough to declare a direct relationship, since he had never seen such a match outside of Asia, he said.
两家公司的差异在于，牛津寻祖公司只检测了罗宾森Y染色体的九个基因标记，发现其中七个与成吉思汗完全符合，塞吉斯并据此推断罗宾森与成吉思汗有血缘关系，因为在亚洲之外，他从没发现过有人能够符合这么多的成吉思汗基因特征。
But the major branches of the Y chromosome family tree are defined by mutations at sites that change very seldom. Oxford Ancestors did not check the slow-mutating site that defines the branch to which Genghis Khan belongs. But at Family Tree DNA, Mr. Greenspan saw a feature in one of the fast-mutating DNA sites that bothered him, and did the costlier test of a slow-mutating site.
只是Y染色体族谱中的主要区段，必须是即使基因突变也不会带来多大改变的地方，而牛津寻祖公司并没有检测这段缓慢突变的区段。相对的，族谱DNA公司因为发现在快速突变的DNA区段中，有一个基因特征让他们十分困惑，于是再进行更昂贵的缓慢突变区段检测，才让真相大白。
A match at 10 fast-mutating sites is outvoted by a discrepancy at one slow-mutating site, Dr. Tyler-Smith said.
根据泰勒史密斯说，即使在快速突变区段发现了十个完全相符的基因特征，只要在缓慢突变区段发现到一个不符，就足以否定两者之间的关系。
|
| |
VOA英语广播收听技巧（2）
FlashFXP下载