The peppered moth - Margaret Drabble

It is 1905, and Bessie is a small child living in a South Yorkshire mining town. Unusually gifted, she sits quietly and studies hard, waiting for the day when she can sit the Cambridge entrance exam and escape the way of life her ancestors have never even thought to question. At the other end of the century her granddaughter, Faro, is listening to a lecture on genetic inheritance. She has returned to the town where her grandmother grew up and sees the families who have lived there for longer than anyone can remember. But for all her exotic ancestry and glamour, has she really travelled any further than them?