In Praise of Flukes

I have an article in tomorrow’s New York Times on a provocative theory about our origins. Humans, other animals, plants, fungi, and protozoans are all eukaryotes. We all share a distinctive genome compared to other organisms (prokaryotes, which include bacteria and archaea). Our genes are more versatile: they can be switched on an off in more complex patterns than in prokaryotes, and one gene can make many different proteins, depending on which parts of the gene our cells look at. Some scientists would like to say that this distinctiveness must be the product of natural selection. But Michael Lynch, a biologist at Indiana University, is here to remind us that natural selection is not the whole story when it comes to evolution. By this he doesn’t mean that the rest of the story involves aliens manufacturing everything we don’t yet understand. He means genetic drift and neutral evolution–processes that dont’ get much attention in the popular press. In writing this article, I figured out why: they’re hard to write about. There are few good metaphors in easy reach for these processes, so you’re left swinging around blunt weapons of statistics. Yet ultimately this is very provocative stuff: it suggests that a great deal at the core of our biological existence emerged in large part thanks to flukes of probability, not thanks to the fine craftsmanship of the blind watchmaker known as natural selection.

The new paper is here. You need a subscription to read it. But a paper Lynch published earlier this year that describes one piece of the puzzle is free.

Update, 1/4 10:30: I’ve posted the full text on carlzimmer.com here.

Update, 1/4 10:40 am: John Travis, deputy news editor at Science comments that he’s surprised that the article did not include comments from other scientists. Actually, it originally did, but in the merciless squeeze to fit on the newspaper page, those quotes had to come out. I contacted four experts in the field, and three had high praise for Lynch’s ideas and one remained skeptical. It’s certainly a controversial idea, since so many efforts in the past to explain the eukaryote genome have proposed that its features emerged as adaptations favored by natural selection.