SmithRNAs: could mitochondria ‘bend’ nuclear regulation?

This poster is part of a broad study on mitochondrial biology, performed through a non-canonical experimental model of mitochondrial inheritance, the Doubly Uniparental Inheritance (DUI), in the Manila clam Ruditapes philippinarum. DUI evolved from maternal inheritance of Mitochondria and has been proposed to be a resolved genomic conflict, triggered by selfish genes of putative viral origin, invading mtDNAs of some bivalve species, and switching ancestral hermaphroditism into gonochorism. Accordingly, mitochondria in DUI species were suggested to affect the genetic cascade of germ line determination, and RNA interference was a reasonable candidate mechanism for this feature. Actually, in libraries of processed small RNAs (i.e. not from RNA turnover) from enriched mitochondrial fractions of clam testes and ovaries, we found several highly transcribed small non coding RNAs (sncRNAs), produced by either F- or M-mtDNAs. We therefore named them: small mitochondrial highly transcribed RNAs (smithRNAs).