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- Genre: Academic theses
Description
Bioarchaeologists often use dental data and spatial analysis of cemeteries to infer the biological and social structure of ancient communities. This approach is commonly referred to as biological distance (“biodistance”) analysis. While permanent crown data feature prominently in these efforts, few studies have verified the accuracy of biodistance methods for recognizing child relatives using deciduous teeth. Thus, as subadults comprise an essential demographic subset of mortuary assemblages, deciduous phenotypes may represent a critical but underutilized source of information on the underlying genetic structure of past populations. The goal of the dissertation is to quantitatively analyze the developmental program underlying deciduous phenotypes and to evaluate their performance in accurately reconstructing known genealogical relationships. This project quantifies morphological variation of deciduous and permanent tooth crowns from stone dental casts representing individuals of known pedigree deriving from three distinct populations: European Canadians, European Australians, and Aboriginal Australians.
To address the paucity of deciduous-focused validation research, phenotypic distances generated from the dental data are subjected to performance analyses (biodistance simulations) and compared to genetic distances between individuals. While family-specific results vary, crown morphology performs moderately well in distinguishing relatives from non-relatives. Comparisons between deciduous and permanent results (i.e., Euclidean distances, Mantel tests, multidimensional scaling output) indicate that deciduous crown variation provides a more direct reflection of the underlying genetic structure of pedigreed samples. The morphology data are then analyzed within a quantitative genetic framework using maximum likelihood variance components analysis. Novel narrow-sense heritability and pleiotropy estimates are generated for the complete suite of deciduous and permanent crown characters, which facilitates comparisons between samples, traits, dentitions, arcades, antimeres, metameres, scoring standards, and dichotomization breakpoints. Results indicate wide-ranging but moderate heritability estimates for morphological traits, as well as low to moderate integration for characters within (deciduous-deciduous; permanent-permanent) and between (deciduous-permanent) dentitions. On average, deciduous and permanent homologues are more strongly genetically correlated than characters within the same tooth row. Results are interpreted with respect to dental development and biodistance methodology. Ultimately, the dissertation empirically validates the use of dental morphology as a proxy for underlying genetic information, including deciduous characters.
To address the paucity of deciduous-focused validation research, phenotypic distances generated from the dental data are subjected to performance analyses (biodistance simulations) and compared to genetic distances between individuals. While family-specific results vary, crown morphology performs moderately well in distinguishing relatives from non-relatives. Comparisons between deciduous and permanent results (i.e., Euclidean distances, Mantel tests, multidimensional scaling output) indicate that deciduous crown variation provides a more direct reflection of the underlying genetic structure of pedigreed samples. The morphology data are then analyzed within a quantitative genetic framework using maximum likelihood variance components analysis. Novel narrow-sense heritability and pleiotropy estimates are generated for the complete suite of deciduous and permanent crown characters, which facilitates comparisons between samples, traits, dentitions, arcades, antimeres, metameres, scoring standards, and dichotomization breakpoints. Results indicate wide-ranging but moderate heritability estimates for morphological traits, as well as low to moderate integration for characters within (deciduous-deciduous; permanent-permanent) and between (deciduous-permanent) dentitions. On average, deciduous and permanent homologues are more strongly genetically correlated than characters within the same tooth row. Results are interpreted with respect to dental development and biodistance methodology. Ultimately, the dissertation empirically validates the use of dental morphology as a proxy for underlying genetic information, including deciduous characters.
ContributorsPaul, Kathleen Siobhan (Author) / Stojanowski, Christopher M. (Thesis advisor) / Buikstra, Jane E. (Committee member) / Schwartz, Gary T. (Committee member) / Taylor, Jesse E. (Committee member) / Arizona State University (Publisher)
Created2017
Description
This study investigated whether the patterns of direct association, and of gene-environment interaction (GxE), between family variables (i.e., parenting, family conflict, and attitudinal familism) and youth externalizing behaviors differed across racial/ethnic groups. The sample was composed of 772 twin pairs from the Adolescent Brain Development Study (ABCD) and analyses were run on three racial/ethnic groups (White [n=1023], Black/African American [n=220], Hispanic [n=152]; Mage=10.14 years). Youth reports of parental warmth, parental monitoring, family conflict, parent-reported attitudinal familism, and parent reports of youth externalizing behaviors were collected at baseline when children were 10 years old. Regression analyses tested the direct association between the family variables and youth externalizing behaviors, and moderated heritability models tested for GxE. Family conflict was associated with more externalizing behaviors for White youth, and parental warmth was associated with fewer externalizing behaviors for Hispanic youth. Parental attitudinal familism composite and familism support were associated with fewer externalizing behaviors for Black youth but more externalizing behaviors for Hispanic youth. We found no effects for parental monitoring, familism obligations, and familism referent on youth externalizing behaviors. Additive genetic and non-shared environmental influences explained the variance in youth externalizing behaviors across all groups. For White youth, parental warmth, parental monitoring, and familism support moderated additive genetic (A), shared-environmental (C), and non-shared environmental (E) influences on externalizing behaviors, and familism obligations moderated C and E influences. Results from exploratory moderated heritability analyses conducted for the Black/African American and Hispanic samples are discussed. Altogether, these findings highlight the multiple avenues through which the family context can impact the development of youth externalizing behaviors, and reinforce the need to examine how these relations differ across racial/ethnic groups.
ContributorsTrevino, Angel Daniel (Author) / Su, Jinni (Thesis advisor) / Lemery-Chalfant, Kathryn (Committee member) / Causadias, Jose (Committee member) / Arizona State University (Publisher)
Created2023