Yesterday’s announcement of the Nobel Prize in Chemistry completed an historic trifecta—American researchers managed to pick up all three science-related Nobel Prizes this year. On Monday, Andrew Z. Fire and Craig C. Mello claimed the Physiology or Medicine prize for their work in RNA interference, explaining how cells can regulate post-transcriptional gene expression (this phenomenon was first noticed—but not understood—in petunias back in the early 1990s). Then physicists John C. Mather and George F. Smoot snagged the Physics prize for finding evidence of the big bang by scouring the cosmic microwave background for telltale irregularities. And rounding out the science prizes, yesterday we heard that Roger D. Kornberg, whose father Arthur won a Nobel Prize for Medicine in 1959, grabbed the Chemistry prize for elucidating how genes are transcribed in eukaryotic cells and determining the physical structure of a key enzyme, RNA polymerase II. We’ll see how American interests fare for the other three Nobels. (Peace prize, anyone?) —Martha Harbison