evolgen

Sorry, dude, but it has to be said. In a feature from the March issue of Seed Magazine (one that doesn’t appear to be available online), Jonah Lehrer profiles six young scientists dubbed “The Truth Seekers”. In his description of Pardis Sabeti, Jonah makes the common error of conflating evolution with natural selection.

Sabeti has helped develop algorithms that use linkage disequilibrium (LD) in DNA sequence polymorphism data to detect evidence for natural selection acting on those regions. She was also involved in a study that identified signatures of natural selection in the malaria parasite, Plasmodium falciparum. Jonah does a decent job of describing how LD can be used to detect natural selection, but he follows it up with this:

Sabeti has already used this “test of evolution” to uncover all sorts of medically relevant genes.

This particular flub also happens to be highlighted in the print version of the article — the text in quotes (which are also present in the original) is encased in a gray box. Jonah’s featured text is flat out wrong. Sabeti’s algorithm doesn’t detect evolution; it detects natural selection. But that’s not the only time Jonah confuses the two:

After inputting a sequence of DNA, her computer was able to pinpoint the invisible signature of natural selection; Sabeti could see exactly where humans had evolved.

If it’s an invisible signature, how do we detect it, Jonah? And the entire human genome has “evolved”. Sabeti was searching for regions that have adaptively evolved in the recent past. That’s an important distinction.