The Paranthropus head is characterized by features traditionally thought to be related to heavy chewing. McCollum [Science 284 (1999) : 301-305] proposed that palatal thickening is a response to developmental integration between the mandibular ramus, oral and nasal functional matrices, and the vomer, which inserts onto the premaxilla in Paranthropus and causes the palate to thicken instead of rotate during vertical expansion. I tested whether palate thickness increases as a byproduct of differential increases in the sizes of the oral and nasal functional matrices compared to growth in the mandibular ramus. To do so, I collected 3D volume and landmark data from computed tomography (CT) scans of extant (Homo sapiens, Pan troglodytes, Gorilla gorilla, Pongo pygmaeus) and extinct taxa (Australopithecus and Paranthropus), and tested counterpart relationships for bones in the cranium using scaling analyses. Results suggest that developmental constraints related to growth counterpart relationships in the skulll are unlikely to affect palate thickness in the genus Paranthropus. / by Brittany A. Burdelsky. / Thesis (M.A.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

The standard representation of evolutionary relationships is a bifurcating tree. However, many types of genetic exchange, collectively referred to as reticulate evolution, involve processes that cannot be modeled as trees. Increasing genomic data has pointed to the prevalence of reticulate processes, particularly in microorganisms, and underscored the need for new approaches to capture and represent the scale and frequency of these events. This thesis contains results from applying new techniques from applied and computational topology, under the heading topological data analysis, to the problem of characterizing reticulate evolution in molecular sequence data. First, we develop approaches for analyzing sequence data using topology. We propose new topological constructions specific to molecular sequence data that generalize standard constructions such as Vietoris-Rips. We draw on previous work in phylogenetic networks and use homology to provide a quantitative measure of reticulate events. We develop methods for performing statistical inference using topological summary statistics. Next, we apply our approach to several types of molecular sequence data. First, we examine the mosaic genome structure in phages. We recover inconsistencies in existing morphology-based taxonomies, use a network approach to construct a genome-based representation of phage relationships, and identify conserved gene families within phage populations. Second, we study influenza, a common human pathogen. We capture widespread patterns of reassortment, including nonrandom cosegregation of segments and barriers to subtype mixing. In contrast to traditional influenza studies, which focus on the phylogenetic branching patterns of only the two surface-marker proteins, we use whole-genome data to represent influenza molecular relationships. Using this representation, we identify unexpected relationships between divergent influenza subtypes. Finally, we examine a set of pathogenic bacteria. We use two sources of data to measure rates of reticulation in both the core genome and the mobile genome across a range of species. Network approaches are used to represent the population of S. aureus and analyze the spread of antibiotic resistance genes. The presence of antibiotic resistance genes in the human microbiome is investigated.

Circuits underlying motor patterns of closely related species provide an ideal framework in which to study how evolution shapes behavioral variation. Male African clawed frogs (Xenopus and Silurana) advertisement call to attract female mates and silence male rivals. Males of each species produce a unique vocal pattern that serves as a species-identifier. Xenopus laevis is the most well-studied species in terms of its vocal behavior and underlying anatomy and physiology. The clade that includes X. laevis, or X. laevis senso lato, also includes 3 other species that diverged ~8.5 million years ago. All 4 of these species produce advertisement calls that include fast trills – trains of fast rate (~60 Hz) sound pulses. However, their calls differ substantially between species in measures of trill duration and period. I examined the premotor circuit underlying vocal patterning in three of these species: X. laevis, X. petersii, and X. victorianus. I used extracellular recordings to find that a premotor nucleus, DTAM, which is part of the vocal central pattern generator, is the likely source of species-variation of vocal patterns. Species-specific trill duration and period are intrinsic to the region of the hindbrain that includes DTAM. Next, I used blind whole-cell patch recordings in DTAM of X. laevis and X. petersii to examine the cells that encode trill duration and period. I identified homologous populations of premotor vocal cells in both species that code for trill duration and period in a species-specific manner. Together, these results support an autonomous role of the DTAM circuit for generation of species variation in call duration and period.

Population genetic structure is difficult to assess in blow flies (Diptera: Calliphoridae) due to high connectivity and genetic diversity of subpopulations. Previous studies revealed high relatedness among individuals within wild samples of blow fly populations, however broad geographic structure was absent. The aim of this research was to determine if blow fly genetic structure exists at a fine spatiotemporal resolution and, if so, to elucidate the influence of environmental factors and resource availability on fly genetics. Specifically, blow fly population genetic patterns were tested against anull hypothesis that flies adhere to a patchy population model with high genetic diversity (i.e. no structure) and high resource availability. Samples of the black blow fly, <i>Phormia regina</i> Meigen (Diptera: Calliphoridae), were collected at six urban parks in Indiana, USA (=urban) in 2016 and 2017 (N = 14 and 16 timepoints, respectively). Additional sampling in different ecoregions was performed to determine if trends observed at a high-resolution scale were also present at a broad geographic scale. Therefore, <i>P. regina</i> were also collected at four sites within two national parks (the Great Smoky Mountains and Yellowstone National Parks) over a three-day period. Randomly selected females (N = 10) from each sample underwent the following analyses: 1) gut DNA extraction, 2) molecular analysis at 6 microsatellite loci, 3) vertebrate-specific 12S and 16S rRNA sequencing, and, 4) vertebrate fecal metabolite screening. Flies from the national parks and a comparable subset of urban data also underwent stable isotopeanalysis (SIA) to determine larval food source. Overall, strong seasonal population genetic structure was observed over both years in the urban environment (2016 F’_ST= 0.47, 2017 F’_ST0.34), however spatial structure was lacking, as seen in previous studies (2016 F’_ST= 0.04, 2017 F’_ST0.03). Weather conditions prior to and on the day of blow fly collections, interspecific competition, and resource availability greatly impacted the genetic diversity and kinship of <i>P. regina</i>. A total of 17 and 19 vertebrate species were detected by flies in 2016 and 2017, respectively, and many flies tested positive for vertebrate feces, suggesting that many varied resources are important for maintaining high gene flow among geographic locations. Genetic diversity was non-existent in flies collected from the Smokies (F’_ST= 0.00), while very slight spatial structure existed in the Yellowstone populations (F’_ST= 0.07). Environmental factors such as temperature, humidity, and wind speed were all statistically relevant in maximizing fly collections with vertebrate resources. In 720 min of total sampling time in the national parks and a subset of urban data, 28 vertebrate species were identified, and fecal resources appeared to be the most abundant in Yellowstone. Stable isotopeanalysis revealed a majority of larval resources in the national parks were herbivores, with a more even distribution of carnivore and herbivore carcasses present in the urban environment, which likely explains the high genetic diversity of adult flies in these regions. Overall, the null hypothesis that <i>P. regina</i> adheres to a patchy population model could not be rejected for the Smokies populations. However, the urban and Yellowstone populations appear to adhere to a Levins metapopulation model in which variable availability in resources leads to random bottleneck events in the local populations. Overall, environmental conditions, competition, and resource availability are all important factors influencing <i>P. regina </i>population genetic structure in different environments.

No description available.

Thesis (M. Sc.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (leaves 73-77) and index. Also available via the World Wide Web.

Thesis (Ph. D.)--University of Chicago, Pritzker School of Medicine, Committee on Genetics, August 2001. / Includes bibliographical references. Also available on the Internet.

Thesis (M. Phil.)--University of Hong Kong, 2010. / Includes bibliographical references (p. 178-187). Also available in print.

Variation in condition can result from environmental heterogeneity or genetic variation affecting resource acquisition and processing ability. Although condition should be positively correlated with the fitness of both males and females, the strength of selection on condition may differ between the sexes due to differences in reproductive variance. Sexual selection on male condition has been proposed to reduce mutation load, but only if selection is greater on males than females. To investigate the strength of selection on condition, the quality of the larval environment was used to manipulate the condition of Drosophila melanogaster. Additionally, selection was measured when the availability of key resources for females (live yeast) and males (access to females) were altered. Overall, selection was found to be stronger on males than females. However, selection on males weakened under a female-biased sex ratio, whereas selection on females was not significantly affected by the abundance of live yeast.

Variation in condition can result from environmental heterogeneity or genetic variation affecting resource acquisition and processing ability. Although condition should be positively correlated with the fitness of both males and females, the strength of selection on condition may differ between the sexes due to differences in reproductive variance. Sexual selection on male condition has been proposed to reduce mutation load, but only if selection is greater on males than females. To investigate the strength of selection on condition, the quality of the larval environment was used to manipulate the condition of Drosophila melanogaster. Additionally, selection was measured when the availability of key resources for females (live yeast) and males (access to females) were altered. Overall, selection was found to be stronger on males than females. However, selection on males weakened under a female-biased sex ratio, whereas selection on females was not significantly affected by the abundance of live yeast.