If the Universe Is Teeming with Aliens ... WHERE IS EVERYBODY?: Seventy-Five Solutions to the Fermi Paradox and the Problem of Extraterrestrial Life

by Stephen Webb

A. As I write this, biologists have announced the production of semisynthetic bacteria whose engineered DNA contain two extra letters, X and Y. In other words, these modified E. coli cells have a third base pair—these cells are a new type of life.