Charles II of Spain (1661-1700), who was infertileSCHLOSS ROHRAUThe Habsburg royal family of Spain, which favored inbred marriages to keep titles in the family and forge alliances, may have evolved from 1450–1800 to blunt the worst effects of inbreeding, according to a study published this month in Heredity. But some geneticists are not convinced, reported Nature.
Evolutionary theory predicts that over time, there will be a purging of the harmful mutations that result from inbreeding. But while the effect has been observed in animals and plants, there is little evidence for this phenomenon in human populations. Researchers from the University of Santiago de Compostela in Spain decided to look for that evidence by analyzing 350 years of genealogical records of the Spanish Hapsburgs, a family with a long history of inbreeding.
Inbreeding increases the probability that offspring will inherit two copies of a recessive disease-causing mutation, but infertility—which may be a consequence of inbreeding—can block such mutations from being passed down. Assuming that early deaths—in infancy, excluding miscarriages and stillbirths, and early childhood, up to the age of 10—were a result ...
