现阶段我国DNA数据库发展的几个关键问题

Several Key Issues for China National DNA Database Development

经过15年发展,我国DNA数据库集聚了3000万以上的STR数据,在超过100万起案件中发挥了作用。随着Y-STR、SNP等新遗传标记被引入法庭科学领域,对DNA数据库的应用已不仅仅满足于传统的直接匹配和简单亲缘关系检索。现阶段我国DNA数据库究竟该向何处发展,文章认为:(1)关于增加DNA数据库支持基因座数量的必要性已在法医遗传学领域达成共识,但常染色体STR基因座数量的增加必须以确定核心基因座为前提。(2)对于SNP等新型遗传标记的采用,DNA数据库应本着"善意期待"和"审慎观望"的态度,在数据库已经进入千万级容量的今天,采用SNP的可能性已经极低,未来能够对DNA数据库带来变革的,很可能是全基因组DNA测序。(3)复杂亲缘关系检索是DNA数据库人口覆盖率不足情况下的合理补充和必然选择,但应遵循严格的规则。(4)在没有通过严谨演绎推理构建起理论框架,特别是结果评价的数学模型之前,Y-STR数据库的应用还只是经验的而不是科学的。综上,作为千万级大容量DNA数据库,涉及发展方向、安全、稳定的根本性问题要慎重从事,用科学的方法思考、规划和推动工作的进行。

China national DNA database has a history of 15 years and has kept more than 30 million short tandem repeat （STR） profiles, generating over 1.5 million matches assisting in more than 1 million investigations. In recent years, Y chromosome STR （Y-STR）, single nucleotide polymorphism （SNP）, single cell testing, and high throughput DNA sequencing technology have been continuously introduced in forensic science. Currently, the DNA database could only allow the traditional direct match and simple mode of familial searching for personal identification, far behind the high-tech assays which is expected. How to utilize these new technologies to develop new stratedgies for China national DNA database？ How to further develop China DNA database and maximize its efficiency？ This paper discusses the development in the light of 4 issues. First of all, the core loci of database need to be set prior to increasing the number of autosomal STR loci, even though there is a consensus on the quantity change. As for the new genetic markers, such as SNP, the attitude of “good will of expectation” should be in line with “prudent wait-and-see”, since there is few possibility to use SNP commonly in a database with ten-million profiles. It is more likely that the genome-wide analysis will bring the great change to the DNA database in the future. Still, the special familial searching is a supplementation and inevitable choice for DNA database in case of a low coverage of the population. But this searching has to follow strict rule. Finally, Y-STR database development is objective and urgent, but it must be cautious as personnel sample collection might be involving legal, social and other problems; the pedigree in sociological term may not equal to genetic one; positive evaluations of Y-STR database should be also built on deductive method; a balanced development of database should be considered of both costs and benefits. Therefore, without a theoretical framework constructed with rigorous deduction, especially prior to the mathematical model of evaluation, Y-STR database is only a matter of empirical, rather than scientific, letting alone the difficulty to assess the value of such experience for others. In conclusion, as a DNA database with ten-millions profiles, any change related to fundamental issues concerned with development, security or stability must be dealt with comprehensively and scientifically.