Arsenic-based life? Not so fast.

Everybody is abuzz with the discovery of a new study that claims to discover a bacteria that can substitute arsenic for phosphorus in its DNA backbone. There's lots of blog coverage of this research, much of it skeptical. If you only read one post about it, I would recommend this one from We Besties. It does a great job of looking at the paper and the experiments from a chemistry standpoint in an easy to understand way. The bottom line seems to be that there are some key experiments needed to be done before we jump the gun on declaring the discovery of alternative biochemistry.

Alternative Biochemistry

"Follow the water" is a common mantra when searching for evidence of extraterrestrial life. After all, you can support life without water, right? But is that necessarily true? Obviously we have a bias towards carbon based life forms since that's what we know, but what about silicon-based? Or an ammonia solvent? The wikipedia entry on the subject of alternative biochemistry is quite expansive on the subject explaining, for example, why silicon wouldn't work. Of course, many of the arguments are still based on certain assumptions built upon how we know life on earth operates, but it's still an interesting read.