Paternal mtDNA and maleness are co-inherited but not causally linked in mytilid mussels.
BACKGROUND
In marine mussels of the genus Mytilus there are two mitochondrial genomes. One is transmitted through the female parent, which is the normal transmission route in animals, and the other is transmitted through the male parent which is an unusual phenomenon. In males the germ cell line is dominated by the paternal mitochondrial genome and the somatic cell line by the maternal. Research to date has not allowed a clear answer to the question of whether inheritance of the paternal genome is causally related to maleness.


RESULTS
Here we present results from hybrid crosses, from triploid mussels and from observations of sperm mitochondria in fertilized eggs which clearly show that maleness and presence of the paternal mitochondrial genome can be decoupled. These same results show that the female mussel has exclusive control of whether her progeny will inherit the mitochondrial genome of the male parent.


CONCLUSIONS
These findings are important in our efforts to understand the mechanistic basis of this unusual mode of mitochondrial DNA inheritance that is common among bivalves.
Kenchington
Ellen L
EL
Department of Fisheries and Oceans, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada. Kenchingtone@mar.dfo-mpo.gc.ca
Hamilton
Lorraine
L
Cogswell
Andrew
A
Zouros
Eleftherios
E
D000818:Animals; D002460:Cell Line; D003433:Crosses, Genetic; D004272:DNA, Mitochondrial; D005260:Female; D016678:Genome; D054629:Genome, Mitochondrial; D005854:Germ Cells / Q000166:cytology; D008297:Male; D008928:Mitochondria / Q000235:genetics; D008957:Models, Genetic; D049878:Mytilus / Q000235:genetics*; D019849:Sex Determination Processes; D012737:Sex Factors; D013094:Spermatozoa / Q000378:metabolism
D004272:DNA, Mitochondrial