Doubly Uniparental Inheritance of Mitochondrial DNA in the Freshwater Bivalve Anodonta woodiana (Bivalvia: Unionidae)

Unlike the vast majority of organisms in which mitochondrial DNA is transmitted maternally (standard mitochondrial inheritance, SMI), some marine or freshwater bivalves exhibit a different pattern of mtDNA transmission, named doubly uniparental inheritance (DUI). In this case there are two types of mtDNA, i.e. the female-transmitted (F-type) and the male-transmitted (M-type), the latter being present only in the male gonads of Unionidae bivalves. Current knowledge on DUI does not cover any freshwater mussels that are found in Poland. This study confirms DUI of mtDNA in A. woodiana, a Chinese mussel discovered in Poland in 1993. The sequence divergence in the COI gene region for the F-type ranged between 0% (separately for Polish and Japanese mussels) and 8.1% (between Polish and Japanese specimens). On the other hand, this parameter was higher for the M-type, reaching 9.7% between Polish and Japanese specimens. Sequence divergence between the F- and M-types reached 34-35% and, although very high, was still characteristic for the bivalves in which DUI had been found.