DNA Barcoding of Head Lice from a ~1500-Year-Old Salt-Preserved Mummy from the Chehrabad Salt Mine, Iran

Human lice can be classified into several mitochondrial clades with distinct geographic distributions, reflecting long-term coevolution with ancient hominids and possibly with human populations. Analysis of ancient lice DNA from archaeological human remains can provide insights into the geographic origins of these clades and the timing of their dispersal. This study analyzes the COI barcode region of lice recovered from the ~1500-year-old salt-preserved mummy (Salt Man 2) at the Chehrabad salt mine in Zanjan Province, Iran. The sequences were compared with those of recent lice from Iran and other regions, available in the GenBank database, to determine clade affiliation and possible historical relationships. Our phylogenetic analysis recovered the five recognized mitochondrial clades (A-E). Ancient lice clustered within clade A but displayed novel haplotypes. Recent nits from Gilan and Kurdistan provinces were grouped within clades A and B, the only clades reported in Iran. The most complete ancient sequence (MLICE005-18) showed close similarity to sequences from Iraq, Pakistan, Egypt, and Iran. These findings, along with future research, could help determine when ancient lice lineages were established or introduced into specific regions. They could also clarify whether they represent haplotypes that have since disappeared or a lineage that still exists in understudied human populations.