Web edition: July 19, 2012 Print edition: August 25, 2012;
Vol.182 #4 (p. 14) Some scientists really throw themselves into
their research, but Stanford University biophysicist Stephen
Quake has taken the all-in approach to a whole new level. Using
his sperm, Quake and colleagues compiled the first-ever genetic
blueprint for a single sperm cell. The results shed new light on
molecular processes such as mutation and recombination in
humans, Quake and his colleagues report in the July 20 Cell.
Figuring out how often humans make mistakes in copying DNA so
that single DNA units are changed, or mutated, is important for
a variety of reasons, including figuring out how long ago humans
diverged from other species, says Laure Ségurel, an evolutionary
geneticist at the University of Chicago. “Every calculation is
based on this mutation rate,” she says. In past studies,
scientists estimated this rate either by comparing human DNA
with that of other species to see how many changes have occurred
since that species split f