A few years back, I noticed a DNA tattoo on the arm of a neuroscientist. He informed me that it spelled out his wife’s initials according to the genetic code. And that enchanting discovery turned me, much to my own surprise, into an amateur anthropologist of scientist body art and the author of Science Ink: Tattoos of the Science Obsessed. (Reviews)

I’ve archived the ~300 tattoos here at National Geographic so that future generations of researchers can analyze them for clues to the folkways of scientists and the scientifically-minded in the early twenty-first century. And I’m still getting fresh ink via email. I will continue to post them here on Saturdays. (The tattoo-averse can thus safely continue reading the Loom while avoiding a scorch of their retinas.)

Continue reading “The Return of the Science Tattoo Emporium” →

We’ve been tinkering with the DNA of other species for thousands of years. We just didn’t know what we were doing.

Starting about ten thousand years ago, humans began to steer the evolution of animals and plants. Our ancestors collected certain seeds instead of others, started to plant them in gardens, and gradually produced domesticated crops. They didn’t know which genetic variants they were choosing, or how those genes helped build new kinds of plants. All they knew was that some plants were better than others. Over thousands of years, for example, an innocuous bush called teosinte turned into tall stalks with gargantuan seeds–otherwise known as corn.

Continue reading “The Evolution of Cavities” →

In 1837, Charles Darwin scribbled a simple tree in a notebook and scrawled above it, “I think.”

That little doodle represented a big idea: that species were descended from common ancestors. They looked different from each other today thanks to the differences that evolved after their lineages split.

Continue reading “Redrawing the Tree of Life” →

About 1800 years ago, a volcano in northern Nicaragua exploded. The crater formed by the eruption slowly filled like a rain barrel. Eventually the water rose high enough to warrant the title of lake. Today it is called Lake Apoyeque. Although Lake Apoyeque is over 300 feet deep, the rains have a long way to before they reach its brim. Lake Apoyeque remains ringed by volcanic cliffs towering as high as 1200 feet. And yet, despite its young age and its remote location, it is filled with fish.

For thirty years, Axel Meyer, an evolutionary biologist now at the University of Konstanz in Germany, has journeyed to Lake Apoyeque and other lakes of Nicaragua to study the evolution of their fish. He and his colleagues have caught cichlids and sequenced their DNA. By comparing their genes, the scientists can work out how the fish spread across the country. At Lake Apoyeque, for example, they found that the cichlids shared a number of mutations with the cichlids of Lake Managua nearby. The fish of Lake Apoyeque have accumulated relatively few mutations of their own. Meyer and his colleagues studied those mutations to estimate how long it took for their genetic diversity to evolve. They concluded that the cichlids came from Lake Managua to Lake Apoyeque only about a century ago.

Continue reading “The Angelina Jolie Project” →