亲缘关系鉴定在法医实践中的需求日益增多，但囿于目前可获得的检测体系的效能限制，对二级及二级以上远亲缘关系的鉴定依然是个难题，经常不能获得明确的鉴定结果，不能充分发挥其证据价值。本项目拟基于下一代测序技术的最新进展，同步检测200个常染色体STR、20个X-STR和30个Y-STR遗传标记，为二级及二级以上远亲缘关系鉴定提供高效能的检测手段。同时，采用IBS评分法对远亲缘关系鉴定获得的大信息量检测数据进行评估。根据实际检测数据和计算机模拟数据，结合STR等位基因丢失、稀有等位基因、突变、连锁、连锁不平衡、重组等因素建立评估模型，进行各级亲缘关系的临界值设定，制定各级亲缘关系评判策略，研制亲缘关系鉴定分析软件。本研究预期能使二级和三级亲缘关系鉴定获得明确的鉴定意见，提高四级和五级亲缘关系的鉴定效能，推动远亲缘关系的鉴定实践，为法庭科学DNA数据库家系搜寻提供新的有价值的解决途径。

The demand for kinship testing is growing in forensic practice. Due to the limitations of the power of current available genotyping systems, it remains a challenge to identify 2nd degree or more distant relationships. Ambiguous identification results cannot be used as valuable source of evidence. This study aims to establish a highly powerful typing system for distant relationships testing. Two hundred autosomal STR, 20 X-STR and 30 Y-STR loci will be detected simultaneously based on next generation sequencing (NGS) platform. Meanwhile, utilizing IBS strategy, the results from real pairwise relatives and simulated samples will be analyzed and an evaluation model will be established. And allele dropout, rare allele, mutation, recombination, linkage and linkage disequilibrium will be taken into consideration. Also the thresholds will be set and served as a standard for judging different degree relationships and software will be designed. It is expected that reliable conclusions can be made for 2nd and 3rd degree relationship testing with the methods established in this study, and the power for 4th and 5th are going to be improved, which will expand traditional paternity testing to more distant relationship testing and provide new approaches for family searching in forensic DNA database.