Ajit Varki profile

2 minute read

Reporter Bruce Lieberman profiles geneticist Ajit Varki in this week’s Nature. It’s a good summary of Varki’s work in sialic acid evolution, focusing on one particular change in the N-glycolyl neuraminic acid (Neu5Gc), work that I touched on here around 3 years ago.

On a molecular level, the difference between Neu5Gc and Neu5Ac is tiny -- a single added oxygen atom perched on one arm distinguishes one from the other (see graphic). But on a biological level, the difference could be enormous. "We thought if monkeys and all of our closest relatives have Neu5Gc and humans don't, then there must be a molecular basis for that," Varki says. He subsequently found it in an enzyme that converts Neu5Ac to Neu5Gc, but which is disabled by mutation in humans.

The article also covers the founding of the Center for Academic Research and Training in Anthropogeny, a research effort of the University of California, San Diego and the Salk Institute. Led by Varki, Margaret Schoeninger, and Pascal Gagneux, the center aims to become an important focus of interdisciplinary work in human origins. I was lucky enough to be invited to one of their research seminars two years ago, and I can say it’s a wonderful environment for collaboration, if the project can continue and build on these small meetings:

Between 1998 and 2007, the Project for Explaining the Origin of Humans drew in anthropologists, primate biologists, geneticists, immunologists, neuroscientists, linguists and many others. They discussed topics ranging from the evolution of language to the differences between humans, Neanderthals and Homo erectus, the first hominid to leave Africa. Goodman says the interdisciplinary nature of the series made it extremely important to the field. "You really had the chance to explore an issue as it relates to the evolutionary origins of our species," he says.
Varki estimates that he has listened to more than 300 talks on various aspects of this discipline. "The idea is the linguist needs to talk to the molecular biologist who needs to talk to the neuroscientist who needs to talk to the psychologist and philosopher about these issues," he says. "Most areas of human knowledge are somewhere relevant."

I think that’s exactly the right attitude – we need more interdisciplinary efforts. I run up against the blind spots of various specialties all the time, and I’m just one person. On the other hand, it is very challenging to get people to invest the time to learn facts outside their narrow field. If this institute helps those efforts, it will be all to the good.


Lieberman B. 2008. Human evolution: details of being human. Nature 454:21-23. doi:10.1038/454021a