A study in humans demonstrated that miRNA expression profiles from blood samples of monozygotic twins show significant differences, with 545 miRNAs found to be differentially expressed across 18 twin pairs. Among these, the miR-4649-5p was identified as a differentially expressed miRNA shared across two pairs of monozygotic twins, suggesting its potential role in distinguishing genetically identical individuals [Xiao et al. DOI:10.1016/j.fsigen.2019.05.003].