Contents

01 June 1973
Vol 180, Issue 4089

About The Cover

First compelte nucleotide sequence of a molecule capable of extracelular replication. Each complementary strand is 218 nucleotides in length. In the test tube, one molecule will autocatalytically generate one trillion (1 X 1012)copies in 20 minutes. See page 916.[D. R. Mills et al., College of Physicians and Surgeons and Surgeons, Columbia University, New York City]