Gender-associated mitochondrial DNA heteroplasmy in the venerid clam Tapesphilippinarum (Mollusca Bivalvia)

This paper provides evidence of a genderassociated mitochondrial DNA (mtDNA ) heteroplasmy in the clam Tapes philippinarum. The pattern of tissue distr ibution of the two observed mtDNA types (referred to as M and Fl parallels that of the doubly uniparental inheritance system of Mytilus. The mitochond rial genetic features of the clam are related to a different rate of evolut ion of the M- and F-type mtDNAs. Since clams are known to be phylogenetical ly very distant from mussels, the present findings support the hypothesis t hat the mechanism producing gender-associated heteroplasmy should be consid ered an ancestral character in the Bivalvia.