Some fruit flies carry up to 60 full copies of their entire mitochondrial genome stashed inside their main nuclear DNA.
April 1, 2026
Original Paper
Evolutionary persistence of a highly prevalent multicopy mitochondrial-derived nuclear insertion (Mega-NUMT) in Neotropical Drosophila flies
bioRxiv · 10.64898/2026.03.31.715258
The Takeaway
While mitochondrial DNA is usually strictly separated from the main nucleus to ensure genetic stability, these flies have copy-pasted their entire 'powerhouse' genome into their main chromosomes dozens of times. This discovery represents an extreme violation of the standard rule of separate mitochondrial inheritance.
From the abstract
Background: Although strict maternal transmission of mitochondria is a general feature of animals and humans for ensuring homogeneity in mitochondrial DNA (mtDNA) across generations, exceptions were reported in the recent past. For example, some extremely rare but spectacular cases of heteroplasmy and paternal transmission in humans have questioned the universal evolutionary principle. Hence, as an alternative, the Mega-NUMT concept was coined to explain this discovery and was thereafter partly