Evolutionary persistence of a highly prevalent multicopy mitochondrial-derived nuclear insertion (Mega-NUMT) in Neotropical Drosophila flies.

A highly prevalent Mega-NUMT with up to 60 mitochondrial genomes is stably integrated into the nuclear genome of Drosophila paulistorum, found in 40% of populations.

• Why it matters: Understanding the persistence and function of Mega-NUMTs challenges the assumption of strict maternal mitochondrial inheritance and could reveal new insights into genome evolution and inheritance mechanisms.
• What they did: Using long-read sequencing and in situ hybridization, the study identified and characterized the organization and prevalence of the Mega-NUMT, which is phylogenetically distinct from current mitotypes.
• The result: The findings suggest the Mega-NUMT has been maintained over long evolutionary periods, possibly through balancing selection or an unknown biological role, highlighting its significance in genome dynamics.