The inheritance of divergent mitochondria in the land snail, Cepaea nemoralis

The mitochondrial genomes of Cepaea nemoralis can differ widely between individuals in the same population. Various hypothesis have been proposed to account for this diversity, including unusually fast evolution and the retention of deep lineages in subdivided populations. Another possibility is that pulmonate mitochondria are inherited in the doubly uniparental mode, as in Mytilus, allowing separate maternal and paternal lineages to coexist. In Mytilus, separate lineages may differ by as much as 20% and may pre-date the origin of the species carrying them. Until now, mitochondrial inheritance has not been studied in any molluscan group except the bivalves. I have investigated it in C, nemoralis through a series of matings, and assayed individuals for evidence of heteroplasmy. In five matings, mitochondrial inheritance was maternal, and no heteroplasmic individuals were detected. The maintenance of the divergent haplotypes can not be explained by doubly uniparental inheritance.