Author(s): Scheidel W
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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.
This article was published in J Biosoc Sci
and referenced in Journal of Biometrics & Biostatistics