Tri-allelic pattern in autosomal STR is a common abnormal typing phenomenon in forensic DNA analysis, which brings difficulties and uncertainties to the evaluation of the evidence weight in actual cases. This paper reviews the types, formation mechanism, occurrence frequency, genetic pattern and quantitative evaluation of evidence of the tri-allelic pattern in autosomal STR in forensic DNA analysis. This paper mainly explains the formation mechanism and genetic patterns based on different types of tri-allelic pattern. This paper also discusses the determination of tri-allelic pattern and the quantitative method of evidence evaluation in paternity testing and individual identification. This paper aims to provide references for scientific and standardized analysis of this abnormal typing phenomenon in forensic DNA analysis.
常染色体STR三等位基因型是法医DNA分析中常见的异常分型现象，给实际检案中证据权重的评估带来困难和不确定性。本文对法医DNA分析中常染色体STR三等位基因型的分类、形成机制、发生率、遗传模式、证据量化评估方法等进行综述，着重基于三等位基因型的不同类型阐述其形成机制及相应的遗传模式，并对三等位基因型的判定及其在亲子鉴定和个体识别中的证据量化评估策略进行讨论，为法医DNA分析中科学化、规范化地解析此类异常分型现象提供参考。.
Keywords: DNA; autosome; forensic genetics; review; short tandem repeats; tri-allelic pattern.