The stochastic behavior of the stutter ratio (SR) in capillary electrophoresis-based DNA typing is currently described and predicted using statistical models in forensic genetics. Clarifying this behavior can help obtain more objective and robust evidence to the court in terms of mixture interpretation. This study aimed to investigate the effect existence of aging on SR via a Bayesian framework. Nail scrapings and clippings were collected from 68 healthy individuals with informed consent. Samples were classified by age-class: young group (0–16 years; n = 36) and older-adult group (>61 years; n = 32). Then, they were compared in terms of their SRs for each simple repeat locus included in GlobalFiler Kit. Bayesian modeling was performed with lognormal distribution model, which implemented multiple linear regression, allele and age-class as explanatory variables. For all simple repeat loci, the median of the posterior distribution of the age-class parameter was a positive value. For CSF1PO and D7S820, the 95% credible interval of the posterior distribution did not include 0. Our data suggested that aging slightly increases the SR. These findings might help elucidate the stochastic behavior of SR.

基于毛细管电泳的 DNA 分型中口吃率 ( SR ) 的随机行为目前使用法医遗传学中的统计模型进行描述和预测。澄清这种行为有助于在混合解释方面向法庭获得更加客观、有力的证据。本研究旨在通过贝叶斯框架研究衰老对SR的影响。在知情同意的情况下，从 68 名健康个体身上收集了指甲屑和剪下的指甲屑。样本按年龄分类：年轻组（0-16 岁；n = 36）和老年组（>61 岁；n = 32）。然后，对 GlobalFiler 套件中包含的每个简单重复基因座的SR进行比较。采用对数正态分布模型进行贝叶斯建模，该模型采用多元线性回归、等位基因和年龄级别作为解释变量。对于所有简单重复基因座，年龄组参数后验分布的中位数为正值。对于 CSF1PO 和 D7S820，​​后验分布的 95% 可信区间不包括 0。我们的数据表明，衰老会略微增加SR。这些发现可能有助于阐明SR的随机行为。