Everything you need to know about biology is in E. coli. Sure, there are some apparent differences between us and a bacterium, but it’s all details … lots and lots of details. That sweet humming core of life — metabolism, replication, communication, evolution — it’s all whirling away in the tiniest of us all, and so you can learn much that is universally applicable by focusing on just one kind of creature.
That, I think, is the message of Carl Zimmer’s latest book, Microcosm(amzn/b&n/abe/pwll). I could argue a little bit with the idea, since a key principle in understanding evolution is the synthetic tension between processes that generate diversity and the historical constraints that define the unity of life, and some of us really like to focus on the details of the diversity, but in general the principle is valid. I can’t think of any general properties of life that aren’t also found in bacteria as well as elephants.
For instance, Zimmer has written a nice introduction to developmental biology here. We usually regard development as a process that produces a variety of well-organized cell types in a multicellular organism, but how plants and animals carry out those processes is embedded right there in single-celled E. coli. Everything we know about genetic regulation, cell signaling, and cell states we learned from François Jacob and Jacques Monod, at least in rough outline. So squid or a corn developmental circuitry is a little more elaborate than the E. coli circuits that Zimmer diagrams in chapter 3 — it’s still the same general story. You need to understand how E. coli can switch on the appropriate enzymes to digest the sugars in its environment before you can understand how a fruit fly cell reads patterning information in its environment to determine its fate.
And then his ninth chapter covers the “evo” in evo-devo. The organism is a palimpsest, with its evolutionary history hidden beneath layers of change, and we can uncover that history by looking at the shifting networks of regulatory circuits. Nifty! It’s clearly a beautiful counter-example against creationism, too.
In principle, this is the kind of book that could be written about any organism, you name it: voles, peach trees, yeast, a beetle, a mold. The cool thing about E. coli, of course, is the depth and volume of information we have about it, and the relative completeness of our understanding. I’ll take the E. coli story for now, until we have a comparable level of information about squid. I hope Carl will write that book, too (it will have to be a bit longer, I suspect, and Carl will have to be many decades older.)