Pre-Columbian Mixtec social organization was distinguished by the tight endogamy of the ruling class, which included many consanguineous marriages. It was also characterized by a vigorous historical and genealogical tradition. The historical documents, or codices, provide materials for the calculation of the levels of inbreeding present before the Spanish Conquest. A genealogical analysis of inbreeding was performed on the combined pedigree, which spanned the tenth through sixteenth centuries, of all individuals connected by ancestry, descent, or marriage with Lord 8 Deer Jaguar Claw of Tilantongo (a .d . 1063-1115). Sixty of the 217 couples (27.65%) were consanguineous. When only couples of wholly known grandparentage were considered (N = 39), F = 0.1051. The mean F of all couples, even those where one spouse was of unknown parentage, was 0.0243. Over the 550 years of the pedigree the maximum F in any 52-year period was 0.1324. This level of inbreeding is sufficient to produce noticeable effects on population structure and affinities over time.
Christensen, Alexander F.
"Ethnohistorical Evidence for Inbreeding among the Pre-Hispanic Mixtec Royal Caste,"
3, Article 8.
Available at: http://digitalcommons.wayne.edu/humbiol/vol70/iss3/8