Introgressed mitochondrial fragments from archaic hominins alter nuclear genome function in modern humans.

Abstract

Archaic introgression introduced functionally relevant variants into modern humans, yet small-scale insertions remain understudied. Here, we leverage 2519 modern human genomes and four high-coverage archaic hominin genomes to systematically characterize nuclear mitochondrial DNA segments (NUMTs). We uncover 483 polymorphic NUMTs across globally diverse human populations and 10 in archaic genomes. By combining overlap with Neanderthal-derived and Denisovan-derived haplotypes, phylogenetic analyses, insertion time estimates, and haplotype colocalization, we identify five NUMTs introduced into modern humans via archaic hominin introgression. Functional analyses reveal that introgressed NUMTs can modulate gene expression, including allele-specific up-regulation of the immune-related gene <i>RASGRP3</i>, and reshape three-dimensional chromatin structure at loci such as <i>SCD5</i> and <i>HNRNPD</i>. These findings highlight an underappreciated mechanism by which archaic mitochondrial fragments shape nuclear genome function and evolution. Our study reframes NUMTs not as passive genomic fossils but as dynamic elements influencing modern human diversity and adaptation.