title: Brother-sister marriage in Roman Egypt.
abstract: According to official census returns from Roman Egypt (first to third centuries CE) preserved on papyrus, 23.5% of all documented marriages in the Arsinoites district in the Fayum (n = 102) were between brothers and sisters. In the second century CE, the rates were 37% in the city of Arsinoe and 18.9% in the surrounding villages. Documented pedigrees suggest a minimum mean level of inbreeding equivalent to a coefficient of inbreeding of 0.0975 in second century CE Arsinoe. Undocumented sources of inbreeding and an estimate based on the frequency of close-kin unions (corrected downwards to 30% for Arsinoe) indicate a mean coefficient of inbreeding of F = 0.15-0.20 in Arsinoe and of F = 0.10-0.15 in the villages at the end of the second century CE. These values are several times as high as any other documented levels of inbreeding. A schematic estimate of inbreeding depression in the offspring of full sibling couples indicates that fertility in these families had to be 20-50% above average to attain reproduction at replacement level. In the absence of information on the amount of genetic load in this population, this estimate may be too high.
authors.affiliation: Darwin College, Cambridge.
authors.forename: W
authors.initials: W
authors.lastname: Scheidel
mesh_terms: D019352:Censuses / Q000266:history; D003241:Consanguinity; D000076144:Egypt, Ancient / Q000453:epidemiology; D005260:Female; D049690:History, Ancient; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D008297:Male; D008393:Marriage / Q000266:history*; D009679:Nuclear Family; D010375:Pedigree; D018644:Roman World / Q000266:history*