Risch N J, Devlin B
Department of Epidemiology and Public Health, Yale University, New Haven, CT 06510.
Science. 1992 Feb 7;255(5045):717-20. doi: 10.1126/science.1738844.
Forensic scientists commonly assume that DNA fingerprint patterns are infrequent in the general population and that genotypes are independent across loci. To test these assumptions, the number of matching DNA patterns in two large databases from the Federal Bureau of Investigation (FBI) and from Lifecodes was determined. No deviation from independence across loci in either database was apparent. For the Lifecodes database, the probability of a three-locus match ranges from 1 in 6,233 in Caucasians to 1 in 119,889 in Blacks. When considering all trios of five loci in the FBI database, there was only a single match observed out of more than 7.6 million comparisons. If independence is assumed, the probability of a five-locus match ranged from 1.32 x 10(-12) in Southeast Hispanics to 5.59 x 10(-14) in Blacks, implying that the minimum number of possible patterns for each ethnic group is several orders of magnitude greater than their corresponding population sizes in the United States. The most common five-locus pattern can have a frequency no greater than about 10(-6). Hence, individual five-locus DNA profiles are extremely uncommon, if not unique.
法医科学家通常假定DNA指纹图谱在普通人群中出现的频率很低，并且基因座间的基因型是相互独立的。为了检验这些假设，研究人员确定了来自联邦调查局（FBI）和Lifecodes的两个大型数据库中匹配的DNA图谱数量。两个数据库中均未发现基因座间存在明显的独立性偏差。对于Lifecodes数据库，三个基因座匹配的概率在高加索人中为1/6233，在黑人中为1/119889。在考虑FBI数据库中所有五个基因座的三联体时，在超过760万次比较中仅观察到一次匹配。如果假定独立性成立，五个基因座匹配的概率在西班牙裔东南部人群中为1.32×10⁻¹²，在黑人中为5.59×10⁻¹⁴，这意味着每个种族群体可能的图谱的最小数量比美国相应的人口规模大几个数量级。最常见的五个基因座图谱的频率不超过约10⁻⁶。因此，即使不是独一无二的，个体的五个基因座DNA图谱也极其罕见。
