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Document Type

Campus-Only Access for One (1) Year

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Anthropology

Year Degree Awarded

2017

Month Degree Awarded

May

First Advisor

Brigitte M. Holt

Second Advisor

Laurie R. Godfrey

Third Advisor

Joseph Hamill

Fourth Advisor

John H. Relethford

Subject Categories

Biological and Physical Anthropology

Abstract

Phenotypic traits develop and are maintained by complex interactions between intrinsic (molecular) and extrinsic (environmental) factors. While the influence of intrinsic factors on adult craniomandibular variation has been intensively studied, less is known about limb bones, in part because it is assumed that their plasticity obscures intrinsic signals, especially those fixed early in life. While diaphyseal regions are plastic in response to activity, the extent to which they also reflect (phylo)genetic autocorrelation has not been sufficiently addressed, particularly given the common practice of comparing long bones across populations unevenly dispersed in space and time.

Here I investigate the degree to which long bone lengths, joints, and diaphyses vary in their ability to detect intrinsic genetic patterns. I do this by calculating among-population genetic relationships via long bone variation in samples from England, Southern Europe, and South Africa. I then test whether these predictions significantly match those generated via craniofacial variation and, further, whether they are supported by contextual (historical) information.

Given the innately plastic nature of diaphyseal regions, I further test whether differences in physical activity can obscure predicted genetic relationships. I do this by adding a temporal component to genetic distance analyses via inclusion of Medieval samples and by partitioning several Southern European samples into “high intensity” and “low intensity” subgroups based on recorded occupational data, using these to generate more genetic predictions.

Results show that all three long bone properties reflect among-population genetic structure, with length and joint dimensions doing so at levels comparable to those of the crania. Diaphyses, however, generate lower levels of among-population differentiation, presumably because their plasticity fuels more intrapopulation variation. Despite this, diaphyses still detect key components of population genetic structure, including genetic affinity shared among modern English and descendant South Africans, the close genetic relationships among modern Southern Europeans (even when subdivided by occupation), and the ancestral connection between Medieval and modern English samples. In total, these results suggest that all long bone properties can detect among-population genetic information, and further, that interpretations of behavior from limb bone variation can be strengthened if genetic relationships (or assumed relationships) are controlled for.

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