Sipe, A.R., A.E. Wilbur and S.C. Cary. 2000. Bacterial symbiont transmission in the wood-boring shipworm Bankia setacea (Bivalvia: Teredinidae). Applied and Environmental Microbiology 66: 1685-1691.
Bankia setacea is not your typical bivalve. What sets them apart from the rest, is their amazing ability to utilize wood as food. To do this, they depend on a special wood digesting bacteria to breakdown the cellulose into simple sugars. In exchange, the bacteria get a safe place to live, within the Gland of Deshayes. How did the bacteria get there and where did they come from, from the sea environment or transmission through the gametes?
Using molecular biology analysis, a rRNA probe was developed for the bacteria by extracting DNA from the bacteria in the gill of the shipworm. This probe was then used to detect the presence of the symbiont in tissue samples taken from the ovary and egg of the shipworm. The hybridization of the rRNA probe with its complement DNA, indicated the presence of the symbiont in both the ovary and egg of the shipworm.
It was also found that B. setacea harbours a different bacteria from other shipworms previously studied. The genetic difference between the two bacteria when analysed was not great, suggesting a recent common ancestor. Results also support the idea that the bacteria are inherited from at least the maternal side in shipworms. It would be interesting to know if this is a recent evolutionary trait specific only to B. setacea or if all shipworms do this? Most likely they all have this way of passing on the symbiont to the next generation and increasing their offspring's chance of success.
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