Tuesday, November 25, 2008

Holy Photosynthesizing Animals Batman!

In these tough days, food items are getting costly, as Fned also noticed recently.

Ever wonder what will be the most extreme ways to cut food costs? Well, worry no more, for a humble sea slug has shown us the way, by adding algal DNA to its own to convert itself to a mean-green slow-moving photon-processing machine!

The new scientist article is here, and the video is here [must watch!].

From the article (all emphasis mine):
[The researcher] has known for some time that E. chlorotica acquires chloroplasts - the green cellular objects that allow plant cells to convert sunlight into energy - from the algae it eats, and stores them in the cells that line its gut.

Young E. chlorotica fed with algae for two weeks, could survive for the rest of their year-long lives without eating, Rumpho found in earlier work.

But a mystery remained. Chloroplasts only contain enough DNA to encode about 10% of the proteins needed to keep themselves running. The other necessary genes are found in the algae's nuclear DNA.


In their latest experiments, Rumpho and colleagues sequenced the chloroplast genes of Vaucheria litorea, the alga that is the sea slug's favourite snack. They confirmed that if the sea slug used the algal chloroplasts alone, it would not have all the genes needed to photosynthesise.

They then turned their attention to the sea slug's own DNA and found one of the vital algal genes was present. Its sequence was identical to the algal version, indicating that the slug had probably stolen the gene from its food.

"We do not know how this is possible and can only postulate on it," says Rumpho, who says that the phenomenon of stealing is known as kleptoplasty.

One possibility is that, as the algae are processed in the sea slug's gut, the gene is taken into its cells as along with the chloroplasts. The genes are then incorporated into the sea slug's own DNA, allowing the animal to produce the necessary proteins for the stolen chloroplasts to continue working.

Another explanation is that a virus found in the sea slug carries the DNA from the algal cells to the sea slug's cells. However, Rumpho says her team does not have any evidence for this yet.

In another surprising development, the researchers found the algal gene in E. chlorotica's sex cells, meaning the ability to maintain functional chloroplasts could be passed to the next generation.

If you didn't click the previous link to see it, now is your time to watch the video.

Sadly, all Chloroplast and DNA is digested to mush in our stomachs, so don't go looking for algae yet :).

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