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.