Status Updates From The Gene: An Intimate History

Rereading as I make one final check on my DNA chapter

"If reproduction failed to produce variants or if heredity failed to transmit variations - then ... the cogwheels of evolution jammed. For Darwin's theory to work, heredity had to possess constancy and inconstancy, stability and mutation"

"Natural selection was not operating on organisms but on their units of heredity. A chicken, de Vries realised, was merely an egg's way of making a better egg"