Contents

21 December 2018
Vol 362, Issue 6421

About The Cover

Cover image expansion

COVER A zebrafish embryo at an early stage of development. Fluorescent markers highlight cells expressing genes involved in determining the type of cell they will become. The ability to track development in stunning detail by marking early embryonic cells to trace their lineage, isolating thousands of cells during development, and sequencing their RNA cell by cell, is Science's 2018 Breakthrough of the Year. See page 1344.
Image: Jeffrey Farrell, Schier Lab/Harvard University