Episode 12: Slime, Slugs, and Slutty Genes

We have emerged triumphant from our move across the country, and are ready to get our geek on! This week’s episode discusses a sea slug that can photosynthesize, and a slime mold that can find the shortest path through a maze. Woah.

The Weinersmiths

P.S.-New microphones are in the mail, and we’re working on improving our internet connection. Sound quality should be improving over the next few episodes!


Paper 1: Maze solving by an amoeboid organism

Slime mold

Physarum polycephalum

Dictyostelium discoideum (“slug” forming slime molds) and the lab of Drs. Strassman & Queller

Paper 2: Horizontal gene transfer of the algal nuclear gene psb0 to the photosynthetic sea slug Elysia chlorotica

Popular press article on this paper

Elysia chlorotica

A book on horizontal gene transfer

8 thoughts on “Episode 12: Slime, Slugs, and Slutty Genes

  1. Morris Keesan

    The unlikely analogy for horizontal gene transfer that immediately came to my mind was the thought of someone being bitten by a radioactive spider, and somehow acquiring spider genes that give him the ability to climb walls (as well as disproportionate strength, deriving from the ability to ignore the square-cube law).
    What’s not clear to me is how sea slug is able to use the energy produced by the photosynthesis. I have no idea of the mechanism by which plants use that energy, but to a non-biologist, it seems strange that an animal would be able to use this same mechanism. More horizontal gene transfer, or is that energy pathway simple enough for it to be non-surprising that the sea slug can do it?

    And, by the way, welcome back, and welcome to the right side of the continent.

    1. Hey

      The plastids produce carbohydrates like starch. Since they are already in the gut epithelium it must not be so dificult for the slug to digest it (like eating potatoes..)

  2. Gelsamel

    For the slime mold, my first thought was of how plants direct themselves towards sunlight. The actual act of consuming the food creates some chemical or hormone that results in a particular growth pattern. In the case of the slime molds the rule could simply be to follow the ‘flow’ of the food through the mold, and since the flow, like most things, probably follows the path of least resistance it’ll end up with the shortest path (as long as we assume that the slime mold is generally uniform).

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  5. Emerson White

    They were slime mold beetles that were named after Bush Cabinet members. Furthermore the scientist contacted them and asked for permission to name them after them, if it was meant as a dishonor I’d expect them to have just gone ahead and done it.


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