[Methods, Applications and Prospects of RNA Polymorphism for Individual Identification]

In recent years, RNA markers have been widely employed for tissue origin identification in forensics. RNA molecules are diverse and can be detected in dried biological stains. They show characteristics such as tissue specificity, spatiotemporal dynamic expression, multi-copy numbers and high polymorphic genetics. Based on these characteristics, RNA genetic markers that combine polymorphism with body fluid specificity have been successfully applied to identify target body fluids in the multi-donor mixed stains. In addition, RNA genetic markers with both multi-copy characteristics and polymorphism have shown promising results in individual identification using anucleate samples such as hair shafts. However, the application of RNA polymorphic genetic markers still faces several key challenges, including the selection of appropriate RNA and polymorphic loci, and optimization of their practical use in forensics. This paper reviews the application of RNA polymorphisms in individual identification and systematically analyzes its advantages, limitations, and the main challenges that need to be addressed in the future. The goals are to further review and consolidate findings from studies of RNA polymorphisms, to advance theoretical development and methodological innovation of RNA polymorphisms in individual identification and to provide references for forensic individual identification.