Ancient mitochondrial DNA and ancestry of Paquimé inhabitants, Casas Grandes (A.D. 1200-1450).

OBJECTIVES: The Casas Grandes (Paquimé) culture, located in the Northwest of Chihuahua, Mexico reached its apogee during the Medio Period (A.D. 1200-1450). Paquimé was abandoned by the end of the Medio Period (A.D. 1450), and the ancestry of its inhabitants remains unsolved. Some authors suggest that waves of Mesoamerican immigrants, possibly merchants, stimulated Paquimé's development during the Medio Period. Archaeological evidence suggests possible ties to groups that inhabited the Southwestern US cultures. This study uses ancient DNA analysis from fourteen samples to estimate genetic affinities of ancient Paquimé inhabitants.

MATERIALS AND METHODS: DNA was extracted from 14 dental ancient samples from Paquimé. PCR and Sanger sequencing were used to obtain mitochondrial control region sequences. Networks, PCoA, and Nei genetic distances were estimated to compare Paquimé haplotypes against available past haplotypes data from Southwestern and Mesoamerican groups.

RESULTS: Haplogroups were characterized for 11 of the samples, and the results revealed the presence of four distinct Amerindian mitochondrial lineages: B (n = 5; 45%), A (n = 3; 27%), C (n = 2; 18%) and D (n = 1; 10%). Statistical analysis of the haplotypes, haplogroup frequencies, and Nei genetic distances showed close affinity of Paquimé with Mimbres.

DISCUSSION: Although our results provide strong evidence of genetic affinities between Paquimé and Mimbres, with the majority of haplotypes shared or derived from ancient Southwest populations, the causes of cultural development at Paquimé still remain a question. These preliminary results provide evidence in support of other bioarchaeological studies, which have shown close biological affinities between Paquimé and Mimbres, a Puebloan culture, in the Southwestern US.