Monday, November 24, 2008

My New Favorite Plant

Botanists everywhere rejoice! Along the lines of the leafy sea dragon, we now have another plant-like animal to admire, the sea slug Elysia chlorotica.

It seems that this sea slug, which feeds on filamentous algae (Vaucheria sp.), intracellularly sequesters algal chloroplasts. Simple enough, right? No. The algae are secondary photosynthesizers, ancient heterotrophs whose ancestors acquired that ability from other algae. Their chloroplasts only encode a small fraction of genes required for their function, while the rest are ordinarily encoded by the nuclear genome. So, how does the sea slug maintain functioning chloroplasts without the supporting cast of nuclear genes? Horizontal gene transfer.

The authors find that at least one gene (psbO)  is encoded by the sea slug's own nuclear genome. It is nearly identical to the algal gene. This strongly argues for the horizontal transfer of photosynthetic ability from prey to predator. Amazing! 

3 comments:

Glor said...

F'ing sweet. Reminds me another recent article on this topic by my colleague Jack Werren, who discovered that genes from the intra-cellular parasite Wolbacchia are regularly transferred to their host's genome. Press report is here .

Glor said...

Screw resurrecting the mammoth, this is something the Times should be writing about! The only decision may be whether to pitch this as a story about plants invading animals or animals stealing from plants...

Poletarac said...

It turns out the name kleptoplasty is already around, reserved for this specific use, and seems fitting.

One could view it as repayment for the orchid/male bee deception, or something, though animals clearly steal more from plants on the balance.