在涉及突变、近亲和亲缘关系鉴定中，需要检验更多的短串联重复序列(short tandem repeat, STR)。然而既往群体研究几乎限于40个以内STR，为此本研究调查了81个常染色体STR基因座在中国北方汉族人群中的遗传多态性、连锁不平衡和突变率情况，确认了STR基因座的核心重复结构，并重点评价了《法庭科学 DNA数据库选用的基因座及其数据结构》(GB/T 41009-2021)中C类和该标准外新增21个STR基因座法医学应用价值。首先，采集400份中国北方汉族健康无关个体血样以及157个家系中父母与孩子血样，利用GSTAR ^TM25以及新研制的GSTAR ^TM31FS和GSTAR ^TM29HS试剂盒进行检测，对81个常染色体STR基因座分型数据进行遗传学分析。本研究对新增的15个STR基因座经测序明确核心序列结构。结果显示，81个常染色体STR基因座经Bonferroni校正之后均符合Hardy-Weinberg平衡，杂合度观测值在0.4375~0.9075之间，个体识别率在0.6332~0.9845之间(LPL基因座最低)，多态性信息含量在0.3938~0.9092之间，三联体非父排除率在0.1384~0.8108之间，二联体非父排除率在0.0955~0.7069之间，D5S2500与D5S2800基因座之间存在连锁不平衡，在不统计D5S2800基因座情形下，80个常染色体STR基因座的累积个体识别率为1-2.293×10^-89，三联体累积非父排除率为1-5.074×10^-31，二联体累积非父排除率为1-1.400×10^-19。观察157个家系中508次减数分裂，在10个STR基因座上有13次突变，D5S818、D11S2368和D18S51基因座突变率为0.004，D6S1043、D7S1517、D11S4463、D13S325、D14S1434、D20S482和D20S85基因座突变率为0.002。结果表明，本研究使用的81个STR基因座多态性为良好或中等，适用于个体识别、亲子鉴定和亲缘关系鉴定。鉴于D5S2500与D5S2800基因座之间存在连锁不平衡，在毛细管电泳平台同时检验时建议仅用D5S2500基因座的检验结果进行统计学分析。本研究提供了大数量STR的等位基因频率数据、突变率，且明确了STR的核心序列，为DNA证据力评估提供重要的数据基础。

Examining a greater number of short tandem repeats (STRs) is essential for cases involving mutations, consanguinity, and complex kinship testing. However, previous population studies were mostly limited to fewer than 40 STRs. Therefore, this study investigated the genetic polymorphism, linkage disequilibrium, and mutation rates of 81 autosomal STR loci in the Han Chinese population of northern China. We confirmed the core repeat structure of STR loci, and focused on evaluating the forensic application value of the Category C and 21 additional STR loci not included in the standard “Forensic science-Data structures of selected loci from the DNA database” (GB/T 41009-2021). Blood samples from 400 unrelated healthy Northern Han Chinese individuals and parent-child blood samples from 157 families were detected using GSTAR ^TM25, GSTAR ^TM31FS, and GSTAR ^TM29HS kits. Genetic analysis was performed on genotyping data of 81 autosomal STR loci. The core sequence structures of newly added 15 STR loci were confirmed by sequencing the allelic ladder. After applying Bonferroni correction, all 81 autosomal STR loci conformed to Hardy-Weinberg equilibrium. The observed heterozygosity ranged from 0.4375 to 0.9075, discrimination power from 0.6332 to 0.9845 (lowest at LPL), polymorphism information content from 0.3938 to 0.9092, probability of exclusion for trios from 0.1384 to 0.8108, and for duos from 0.0955 to 0.7069. Significantly, linkage disequilibrium was observed between D5S2500 and D5S2800 loci. When excluding the D5S2800 locus, the cumulative discrimination power (CDP) of remaining 80 autosomal STR loci was 1-2.293×10^-89, cumulative probability of exclusion (CPE) of trios was 1-5.074×10^-31, and cumulative exclusion probability of duos was 1-1.400×10^-19. A total of 13 mutations were observed across 508 meiotic events in 157 families at 10 STR loci. The mutation rates for D5S818, D11S2368 and D18S51 were 0.004, while those of D6S1043, D7S1517, D11S4463, D13S325, D14S1434, D20S482 and D20S85 were 0.002. In conclusion, the 81 genetic loci, including Category C and newly added STRs, exhibit good or moderate polymorphism and are suitable for individual identification, paternity testing, and kinship identification. Given the linkage disequilibrium between the D5S2500 and D5S2800, if simultaneous on the capillary electrophoresis platform, it is recommended to use only the test results from the D5S2500 locus for statistical analysis. This data generated provide allele frequency and mutation rate for a large number of STRs, along with the clarified core sequences, thus offering an important data foundation for DNA evidence evaluation.