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- All Subjects: Genetics
- Genre: Academic theses
- Creators: Chassin, Laurie
- Member of: Theses and Dissertations
Description
The present study tested the factor structure of the externalizing disorders (e.g. attention-deficit hyperactivity disorder (ADHD), conduct disorder (SE), and substance experimentation (SE) ) in adolescence. In addition, this study tested the influence of the GABRA2 gene on the factors of the externalizing spectrum. Confirmatory factor analyses were used to test the factor structure of the externalizing spectrum. Specifically, three competing alternate confirmatory factor analytic models were tested: a one-factor model where all disorders loaded onto a single externalizing factor, a two-factor model where CD and SE loaded onto one factor and ADHD loaded onto another, and a three-factor model, where all three disorders loaded onto separate factors. Structural equation modeling was used to test the effect of a GABRA2 SNP, rs279858, on the factors of the externalizing spectrum. Analyses revealed that a three-factor model of externalizing disorders with correlated factors fit the data best. Additionally, GABRA2 had a significant effect on the SE factor in adolescence, but not on the CD or ADHD factors. These findings demonstrate that the externalizing disorders in adolescence share commonalities but also have separate sources of systematic variance. Furthermore, biological mechanisms may act as a unique etiological factor in the development of adolescent substance experimentation.
ContributorsWang, Frances L (Author) / Chassin, Laurie (Thesis advisor) / Lemery-Chalfant, Kathryn (Committee member) / Geiser, Christian (Committee member) / Arizona State University (Publisher)
Created2012
Description
In species with highly heteromorphic sex chromosomes, the degradation of one of the sex chromosomes can result in unequal gene expression between the sexes (e.g., between XX females and XY males) and between the sex chromosomes and the autosomes. Dosage compensation is a process whereby genes on the sex chromosomes achieve equal gene expression which prevents deleterious side effects from having too much or too little expression of genes on sex chromsomes. The green anole is part of a group of species that recently underwent an adaptive radiation. The green anole has XX/XY sex determination, but the content of the X chromosome and its evolution have not been described. Given its status as a model species, better understanding the green anole genome could reveal insights into other species. Genomic analyses are crucial for a comprehensive picture of sex chromosome differentiation and dosage compensation, in addition to understanding speciation.
In order to address this, multiple comparative genomics and bioinformatics analyses were conducted to elucidate patterns of evolution in the green anole and across multiple anole species. Comparative genomics analyses were used to infer additional X-linked loci in the green anole, RNAseq data from male and female samples were anayzed to quantify patterns of sex-biased gene expression across the genome, and the extent of dosage compensation on the anole X chromosome was characterized, providing evidence that the sex chromosomes in the green anole are dosage compensated.
In addition, X-linked genes have a lower ratio of nonsynonymous to synonymous substitution rates than the autosomes when compared to other Anolis species, and pairwise rates of evolution in genes across the anole genome were analyzed. To conduct this analysis a new pipeline was created for filtering alignments and performing batch calculations for whole genome coding sequences. This pipeline has been made publicly available.
In order to address this, multiple comparative genomics and bioinformatics analyses were conducted to elucidate patterns of evolution in the green anole and across multiple anole species. Comparative genomics analyses were used to infer additional X-linked loci in the green anole, RNAseq data from male and female samples were anayzed to quantify patterns of sex-biased gene expression across the genome, and the extent of dosage compensation on the anole X chromosome was characterized, providing evidence that the sex chromosomes in the green anole are dosage compensated.
In addition, X-linked genes have a lower ratio of nonsynonymous to synonymous substitution rates than the autosomes when compared to other Anolis species, and pairwise rates of evolution in genes across the anole genome were analyzed. To conduct this analysis a new pipeline was created for filtering alignments and performing batch calculations for whole genome coding sequences. This pipeline has been made publicly available.
ContributorsRupp, Shawn Michael (Author) / Wilson Sayres, Melissa A (Thesis advisor) / Kusumi, Kenro (Committee member) / DeNardo, Dale (Committee member) / Arizona State University (Publisher)
Created2016
Description
The current study utilized data from two longitudinal samples to test mechanisms in the relation between a polygenic risk score indexing serotonin functioning and alcohol use in adolescence. Specifically, this study tested whether individuals with lower levels of serotonin functioning as indexed by a polygenic risk score were vulnerable to poorer self-regulation, and whether poorer self-regulation subsequently predicted the divergent outcomes of depressive symptoms and aggressive/antisocial behaviors. This study then examined whether depressive symptoms and aggressive/antisocial behaviors conferred risk for later alcohol use in adolescence, and whether polygenic risk and effortful control had direct effects on alcohol use that were not mediated through problem behaviors. Finally, the study examined the potential moderating role of gender in these pathways to alcohol use.
Structural equation modeling was used to test hypotheses. Results from an independent genome-wide association study of 5-hydroxyindoleacetic acid in the cerebrospinal fluid were used to create serotonin (5-HT) polygenic risk scores, wherein higher scores reflected lower levels of 5-HT functioning. Data from three time points were drawn from each sample, and all paths were prospective. Findings suggested that 5-HT polygenic risk did not predict self-regulatory constructs. However, 5-HT polygenic risk did predict the divergent outcomes of depression and aggression/antisociality, such that higher levels of 5-HT polygenic risk predicted greater levels of depression and aggression/antisociality. Results most clearly supported adolescents’ aggression/antisociality as a mechanism in the relation between 5-HT polygenic risk and later alcohol use. Deficits in self-regulation also predicted depression and aggression/antisociality, and indirectly predicted alcohol use through aggression/antisociality. These pathways to alcohol use might be the most salient for boys with low levels of socioeconomic status.
Results are novel contributions to the literature. The previously observed association between serotonin functioning and alcohol use might be due, in part, to the fact that individuals with lower levels of serotonin functioning are predisposed towards developing earlier aggression/antisociality. Results did not support the hypothesis that serotonin functioning predisposes individuals to deficits in self-regulatory abilities. Findings extend previous research by suggesting that serotonin functioning and self-regulation might be transdiagnostic risk factors for many types of psychopathology.
Structural equation modeling was used to test hypotheses. Results from an independent genome-wide association study of 5-hydroxyindoleacetic acid in the cerebrospinal fluid were used to create serotonin (5-HT) polygenic risk scores, wherein higher scores reflected lower levels of 5-HT functioning. Data from three time points were drawn from each sample, and all paths were prospective. Findings suggested that 5-HT polygenic risk did not predict self-regulatory constructs. However, 5-HT polygenic risk did predict the divergent outcomes of depression and aggression/antisociality, such that higher levels of 5-HT polygenic risk predicted greater levels of depression and aggression/antisociality. Results most clearly supported adolescents’ aggression/antisociality as a mechanism in the relation between 5-HT polygenic risk and later alcohol use. Deficits in self-regulation also predicted depression and aggression/antisociality, and indirectly predicted alcohol use through aggression/antisociality. These pathways to alcohol use might be the most salient for boys with low levels of socioeconomic status.
Results are novel contributions to the literature. The previously observed association between serotonin functioning and alcohol use might be due, in part, to the fact that individuals with lower levels of serotonin functioning are predisposed towards developing earlier aggression/antisociality. Results did not support the hypothesis that serotonin functioning predisposes individuals to deficits in self-regulatory abilities. Findings extend previous research by suggesting that serotonin functioning and self-regulation might be transdiagnostic risk factors for many types of psychopathology.
ContributorsWang, Frances Lynn (Author) / Chassin, Laurie (Thesis advisor) / Eisenberg, Nancy (Committee member) / Lemery-Chalfant, Kathryn (Committee member) / MacKinnon, David (Committee member) / Arizona State University (Publisher)
Created2017
Description
Pediatric chronic pain is pervasive and associated with myriad adverse consequences, yet due consideration has not been given to the mental health disturbances that often present alongside chronic pain and the etiological mechanisms that potentially underlie both. The current study examined the etiology underlying chronic pain and internalizing symptomology in middle childhood, considering both independent and co-occurring symptom presentations. Phenotypic parent-offspring associations across chronic pain and internalizing symptomology were also examined. Lastly, nuclear twin family models were tested to determine the extent to which genetic and environmental factors underlie parent-offspring transmission. The sample comprised 795 children (399 families; Mage= 9.7 years; SD = 0.92) and their parents drawn from the Arizona Twin Project. Results indicated that chronic pain was highly heritable (78%), whereas internalizing symptomology was modestly heritable (32%) and further subject to moderate shared environmental influence (50%). Moreover, 9% of the variance in chronic pain was explained by additive genetic factors shared with internalizing symptomology. Maternal chronic pain and internalizing symptomology were positively associated with both child chronic pain and internalizing symptomology. The association between maternal chronic pain and child chronic pain was more pronounced for girls than boys, whereas the association between maternal internalizing symptomology and child internalizing symptomology was more pronounced for boys than girls. Paternal chronic pain was not significantly associated with child chronic pain but was unexpectedly associated with lower child internalizing symptomology. The negative association between paternal chronic pain and child internalizing symptomology was more pronounced for boys than girls. Paternal internalizing symptomology was not significantly associated with child chronic pain but was positively associated with child internalizing symptomology. Lastly, the best fitting reduced nuclear twin family models for both chronic pain and internalizing symptomology retained additive genetic, sibling-specific shared environmental, and nonshared environmental parameters, where parent-offspring transmission was solely explained by shared genetics and sibling-specific shared environmental factors further accounted for co-twin resemblance. Results provide novel insight into common liabilities underlying chronic pain and internalizing symptomology in middle childhood, parent-offspring associations across chronic pain and internalizing symptomology, and the etiological mechanisms that explain symptom aggregation across generations.
ContributorsOro, Veronica (Author) / Lemery-Chalfant, Kathryn (Thesis advisor) / Chassin, Laurie (Committee member) / Davis, Mary (Committee member) / Su, Jinni (Committee member) / Arizona State University (Publisher)
Created2021