iPad Notebook export for The Gene: An Intimate History

August 13, 2016

Quotes from the book I particularly liked:

I use that last adjective—dangerous with full cognizance. Three
profoundly destabilizing scientific ideas ricochet through the
twentieth century, trisecting it into three unequal parts: the atom,
the byte, the gene. Each is foreshadowed by an earlier century, but
dazzles into full prominence in the twentieth…each represents the irreducible unit—the building
block, the basic organizational unit—of a larger whole: the atom, of
matter; the byte (or “bit”), of digitized information; the gene, of
heredity and biological information.

has long been a biologist’s conundrum: If there is no mechanism to “lock” fate forward, there should be no mechanism to lock it backward. If genetic switches are transient, then why isn’t fate or memory transient? Why don’t we age backward? This question bothered Conrad Waddington, an English embryologist working in the 1950s. When Waddington considered the development of an animal embryo, he saw the genesis of thousands of diverse cell types—neurons, muscle cells, blood, sperm—out of a single fertilized cell. Each cell, arising from the original embryonic cell, had the same set of genes. But if genetic circuits could be turned on and off transiently, and if every cell carried the same gene sequence, then why was the identity of any of these cells fixed in time and place? Why couldn’t a liver cell wake up one morning and find itself transformed into a neuron?

Could one compare the “RNA catalog” of two different cells, and thereby clone a functionally relevant gene from that catalog? The biochemist’s approach pivots on concentration: find the protein by looking where it’s most likely to be concentrated…
it out of the mix. The geneticist’s approach, in contrast, pivots on information : find the gene by searching for differences in “databases” created by two closely related cells and multiply the gene in bacteria via cloning. The biochemist distills forms; the gene cloner amplifies information.