Proof of hereditary elites at Chaco

Archaeogenomic evidence reveals prehistoric matrilineal dynasty

Nature Communications 8, Article number: 14115 (2017)

Douglas J. Kennett, Stephen Plog, Richard J. George, Brendan J. Culleton, Adam S. Watson, Pontus Skoglund, Nadin Rohland, Swapan Mallick, Kristin Stewardson, Logan Kistler, Steven A. LeBlanc, Peter M. Whiteley, David Reich & George H. Perry

For societies with writing systems, hereditary leadership is documented as one of the hallmarks of early political complexity and governance. In contrast, it is unknown whether hereditary succession played a role in the early formation of prehistoric complex societies that lacked writing. Here we use an archaeogenomic approach to identify an elite matriline that persisted between 800 and 1130 CE in Chaco Canyon, the centre of an expansive prehistoric complex society in the Southwestern United States. We show that nine individuals buried in an elite crypt at Pueblo Bonito, the largest structure in the canyon, have identical mitochondrial genomes. Analyses of nuclear genome data from six samples with the highest DNA preservation demonstrate mother–daughter and grandmother–grandson relationships, evidence for a multigenerational matrilineal descent group. Together, these results demonstrate the persistence of an elite matriline in Chaco for ~330 years.

From the article: Fig. 2: Radiocarbon and archaeogenomic results for individuals buried in room 33. (a) Bayesian chronological model of calibrated AMS 14C dates for burials 13 and 14 and the estimated age of the wood plank floor, and calibrated AMS 14C dates for nine other crania above the floor in room 33. Calibrated 67.2 and 95.4% AMS date ranges and calibrated posterior probability distributions are illustrated for each cranium. (b) Archaeogenomic relatedness results for mtDNA (nucleotide sequence similarity to burial 14) and the nuclear genome. For the nuclear genome analysis, the estimated relatedness coefficient r (with the 95% confidence interval) is shown for each of the two pairs of individuals with significant genetic relationships. (c) The ratio Ry of the number of non-redundant sequence reads for each individual that mapped to human chromosome Y to the number of total reads that mapped to chromosomes X and Y, with the total number of X+Y reads and the 95% confidence interval indicated. Shaded areas indicate the Ry boundaries corresponding to confident male and female designations, determined with individuals of known sex25. The genetic sex estimates are compared with those from a previous osteological analysis18. Graphical layout: T. Harper. . . .