Biological Distance Analysis of Identity, Postmarital Residence, and Population Structure at the CA-ALA-11 Shellmound
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Authors
Broehl, Kristen A.
Issue Date
2023
Type
Dissertation
Language
Keywords
Bioarchaeology , Biodistance , California , Shellmound
Alternative Title
Abstract
This research focused on CA-ALA-11, an Ancestral Ohlone shellmound in Alameda,California on the east shore of San Francisco Bay. Shellmounds are unique monumental features constructed by Indigenous peoples along waterways of the Bay Area for a range of ceremonial, mortuary, and domestic functions. Recent archaeological excavations at ALA-11 recovered 182 burials which were analyzed with permission of the site’s Most Likely Descendant. I used biological distance (biodistance) analyses of dental and skeletal non-metric and metric phenotypic traits to explore three questions related to population structure and composition at the site. First, I used intra-site biodistance methods to investigate whether spatial proximity or mortuary characteristics (double burials and burial orientation, flexion, or position) corresponded with biological affinity, since kinship has been proposed to explain burial traits in the region. Most tests showed no identifiable trends between mortuary identity and biological relatedness. However, pairs of individuals from double graves were consistently distant and likely reflected temporal patterning due to grave reuse. The second question compared variation between females and males to examine postmarital residence patterns at the site. Results indicated similar levels of within-sex phenotypic variation, consistent with approximately equal mobility. Access to both partners’ kin networks may have been important for ensuring access to resources as groups became more territorial, although there may also be trends that were obscured by low temporal resolution. The third question evaluated bioaffinity between the ALA-11 cemetery population and burials from other central California archaeological sites. Craniometric similarities between a temporal subset (Middle 2) of the ALA-11 sample and a site from the San Joaquin Delta were consistent with the spread of a Meganos population from the Delta to the Bay around that time, although small sample sizes precluded conclusive results. ALA-11 showed very low frequencies of extended burials, which are typically associated with the Meganos. The mismatch between biological and burial evidence at the site supported recent population movement models that showed a gradual adoption of Meganos traits related to gene flow rather than widescale population replacements. Together, the three studies in this dissertation provide insight into the genetic makeup of the ALA-11 population as well as how biological affinity factored into cultural identity formation and expression.