LIFE’S GREATEST SECRET

Animal breeders have always known that “like breeds like,” but no one, Charles Darwin included, knew why offspring resemble parents except, sometimes, when they don’t. Cobb (Zoology/Univ. of Manchester; Eleven Days in August: The Liberation of Paris 1944, 2014, etc.) describes how they learned.

One of the only defects of his fine history of genetics is the title. There was rarely a race to figure out the genetic code but rather a stream of advances that began with the 17th-century speculation of the great physician William Harvey, sped up after the 1900 rediscovery of Mendel’s laws, and accelerated still more in 1943, when Oswald Avery and Maclyn McCarty showed that DNA contained the genetic code. (This was perhaps the greatest discovery that didn’t win a Nobel Prize.) The DNA molecule is so simple that many scientists found this hard to accept, but by 1953, when James Watson and Francis Crick revealed its structure, they knew where to look. Details of how this deceptively uniform molecule guides production of a living organism began pouring out with the arrival of computers and the information revolution during the following decades. Genetics is, after all, information. Unraveling the code and putting it to work, writes Cobb, “was a leap forward in humanity’s understanding of the natural world and our place within in, akin to the discoveries of Galileo and Einstein in the realm of physics or the publication of Darwin’s On the Origin of Species. These comparisons are not the fruit of hindsight, they were made at the time.”

The greatest milestone in 20th-century biology received an iconic account in Horace Freeland Judson’s The Eighth Day of Creation (1979). Much has happened since that publication, and Cobb’s gripping, insightful history, often from the mouths of the participants themselves, updates the story, bringing it all the way into the present.