1953    James D. Watson and Francis Crick announce to friends that they have determined the chemical structure of DNA; the formal announcement takes place on April 25 following publication in April Nature (pub. April 2).

1994    Human evolution: The journal ''Nature'' reports the finding in Ethiopia of the first complete ''Australopithecus afarensis'' skull.

2001    First draft of the complete Human Genome is published in Nature

2003    Human evolution: The journal Nature reports that 350,000-year-old footprints of an upright-walking human have been found in Italy.