Author: Laurence D. Hurst

If we start with the presumption that evolution is a constantly improving process, some aspects of our evolution just do not make sense. We have a high rate of genetic diseases, for example, and much of our DNA seems to be pointless.

In “The Evolution of Imperfection,” Laurence Hurst explores our apparently rotten genetic luck.

Hurst, a leading authority on evolution and genetics, argues that our evolutionary imperfections proceed directly from two features: the difficulties of pregnancy and the fact that historically there are relatively few of us.

In pregnancy, natural selection can favor chromosomes that kill embryos in species (including ours) that continuously receive resources from the mother. Most fertilized eggs don’t make it, and incompatibilities between the fetus and mother can lead to lethal disorders of pregnancy.

The historically small population size enhances the role of chance, which in turn leads to both accumulation of unnecessary DNA and more mutation.