Freshwater bivalves from the family Unionidae usually have two very divergent mitogenomes, inherited according to the doubly uniparental model. The early divergence of these two mitogenomic lineages gives a unique opportunity to use two mitogenomic data sets in a single phylogenetic context. However, the number of complete sequences of the maternally inherited mitogenomes of these animals available in GenBank greatly exceeds that of the paternally inherited mitogenomes. This is a problem for phylogenetic reconstruction because it limits the use of both mitogenomic data sets. Moreover, since long branch attraction phenomenon can bias reconstructions if only a few but highly divergent taxa are considered, the shortage of the faster evolving paternally inherited mitogenome sequences is a real problem. Here we provide, for the first time, complete sequences of the M mitogenomes sampled from Polish populations of two species: native Unio pictorum and invasive Sinanodonta woodiana. It increases the available set of mitogenomic pairs to 18 species per family, and allows unambiguous reconstruction of phylogenetic relationships among them. The reconstructions based on M and F mitogenomes which were separated for many millions of years, and subject to differing evolutionary dynamics, are fully congruent.
Keywords: DUI; Mitogenomics; Molecular clock; Phylogeny; mtDNA.