Rootless hair as a reliable source of forensic genetic information

Abstract

The small amount of fragmented DNA present in rootless hair shafts is unsuitable for many assays, including most PCR-based assays. Thus, rootless hair DNA is often overlooked in biomedical and forensic analysis. Here we apply methods for efficient recovery and sequencing of minute quantities of short, fragmented DNA to single human hair shafts. Using this approach, we characterize DNA fragments in hair shafts. Despite the small quantities of fragmented DNA, we find multi-fold genome coverage can be generated from a few centimeters of most hair shafts – enough to generate accurate genotype calls and statistically compelling evidence for identity or non-identity. Supplementary Information The online version contains supplementary material available at 10.1186/s13059-026-03981-8.