The Date in the Gut
Two peoples in Bolivia and Tanzania, whose ancestors parted tens of thousands of years ago, carry more than 1,200 of the same gut bacteria. The bacteria's DNA also holds a date for when their lines last traded genes: about 17,000 years ago. Scroll to see how a clock is read out of the letters.
The Powerhouse With No Power
School diagrams call the mitochondrion the powerhouse of the cell. In the parasite Giardia, what remains has no DNA, carries 59 proteins, and makes no energy.
The 1:4 Rule
A Costa Rican epiphyte arrived in the tent already flowering. Its leaves follow one rule, its flowers follow another, and the genus holding both is younger than the compact disc.
The Chinese Money Plant Is Doing Geometry
A common houseplant turns out to divide its own leaf the way a city divides school districts. The interesting part is what it takes to prove that.