Data from: Royal dynasties as human inbreeding laboratories: the Habsburgs

The European royal dynasties of the Early Modern Age provide a useful framework for human inbreeding research. In this article, consanguineous marriage, inbreeding depression and the purging of deleterious alleles within a consanguineous population are investigated in the Habsburgs, a royal dynasty with a long history of consanguinity over generations. Genealogical information from a number of historical sources was used to compute kinship and inbreeding coefficients for the Habsburgs. Marriages contracted by the Habsburgs from 1450 to 1750 presented an extremely high mean kinship (0.0628 {plus minus} 0.009), which was the result of the matrimonial policy conducted by the dynasty to establish political alliances through marriage. A strong inbreeding depression for both infant and child survival was detected in the progeny of 71 Habsburg marriages in the period 1450-1800. The inbreeding load for child survival experienced a pronounced decrease from 3.98 {plus minus} 0.87 in the period 1450-1600 to 0.93 {plus minus} 0.62 in the period 1600-1800, temporal changes in the inbreeding depression for infant survival were not detected. Such reduction of inbreeding depression for child survival in a relatively small number of generations could be caused by elimination of deleterious alleles of large effects according with predictions from purging models. The differential purging of the infant and child inbreeding loads suggests that the genetic basis of inbreeding depression was probably very different for infant and child survival in the Habsburg lineage. Our findings provide empirical support that human inbreeding depression for some fitness components might be purged by selection within consanguineous populations.