Scientia Pro Publica #19 is up

Scientia Pro Publica, the science blog carnival, has a new edition up at Deep Thoughts and Silliness, and it has several posts on evolution.

For example, in The Non-Line Between Life and Not-Life Andrew Bernardin argues that prions are fuzzying the boundary between life and non-life, because of the observation that prions can evolve. However, this assumes first that life is well defined by that which evolves, which I think it very not true. Lots of other things can evolve that we would not call life, like strings of numbers in a computer, inorganic molecules, and memes. And, much like memes, prions don't really reproduce. They are expressed by mammalian genes, and are found all over in our bodies. The prions that cause disease are misfolded. A misfolded protein can induce misfolding in a properly folded prion by a method that still isn't quite well understood, and while it is beneficial to think of this as reproduction, and really is more like a cultural propagation of ideas. Or a game of tag.

Not that I think the line between life and non-life isn't fuzzy, though.

Gerald Joyce also includes the capability to evolve as a necessary component in his definition of life, which I disagree with, though he doesn't say it is a sufficient condition, at least.

Here are two previous posts with links to new articles about prions: Evolution highlights VII and X.