abstract: Vertebrate genomes demonstrate a remarkable range of sizes from 0.3 to 133 gigabase pairs. The proliferation of repeat elements are a major genomic expansion. In particular, long interspersed nuclear elements (LINES) are autonomous retrotransposons that have the ability to "cut and paste" themselves into a host genome through a mechanism called target-primed reverse transcription. LINES have been called "junk DNA," "viral DNA," and "selfish" DNA, and were once thought to be parasitic elements. However, LINES, which diversified before the emergence of many early vertebrates, has strongly shaped the evolution of eukaryotic genomes. This thesis will evaluate LINE abundance, diversity and activity in four anole lizards. An intrageneric analysis will be conducted using comparative phylogenetics and bioinformatics. Comparisons within the Anolis genus, which derives from a single lineage of an adaptive radiation, will be conducted to explore the relationship between LINE retrotransposon activity and causal changes in genomic size and composition. / Dissertation/Thesis / M.S. Biology 2013

No description available.

Due to its significance in many cellular functions, fatty acid binding protein 7 (FABP7) has become a rising topic of interest for many scientists. Immunocytochemistry was used to map the distribution of FABP7 and test whether the amount of FABP7 immunoreactivity (FABP7-IR) differed in animals that were defeated in a fight, as compared to control animals that did not engage in any social interaction. The male green anole was used as the subject because its natural tendency to establish social classes within its species provides an ideal model to observe for variation in FABP7-IR. The results showed FABP7-IR in cells and fibers of the cortex, hypothalamus, thalamus, medial preoptic area, dorsoventricular ridge, amygdala, suprachiasmatic nucleus, nucleus accumbens, nucleus rotundus, habenular area, tectum, dorsal noradrenergic and lateral forebrain bundles, and lining the third and lateral ventricles. Qualitative observation suggested higher FABP7 levels in socially defeated males than controls in all areas.

abstract: Damage to the central nervous system due to spinal cord or traumatic brain injury, as well as degenerative musculoskeletal disorders such as arthritis, drastically impact the quality of life. Regeneration of complex structures is quite limited in mammals, though other vertebrates possess this ability. Lizards are the most closely related organism to humans that can regenerate de novo skeletal muscle, hyaline cartilage, spinal cord, vasculature, and skin. Progress in studying the cellular and molecular mechanisms of lizard regeneration has previously been limited by a lack of genomic resources. Building on the release of the genome of the green anole, <i>Anolis carolinensis</i>, we developed a second generation, robust RNA-Seq-based genome annotation, and performed the first transcriptomic analysis of tail regeneration in this species. In order to investigate gene expression in regenerating tissue, we performed whole transcriptome and microRNA transcriptome analysis of regenerating tail tip and base and associated tissues, identifying key genetic targets in the regenerative process. These studies have identified components of a genetic program for regeneration in the lizard that includes both developmental and adult repair mechanisms shared with mammals, indicating value in the translation of these findings to future regenerative therapies. / Dissertation/Thesis / Doctoral Dissertation Molecular and Cellular Biology 2015

Among species, populations, and individuals, there exists a tremendous amount of variation in how hosts respond to, and are thus protected from parasites. Such variation inevitably affects host-parasite dynamics and ultimately how parasites will move through and evolve in communities. A likely factor in the diversity of immune responses seen in nature are the costs associated with activation of the immune system upon exposure to parasites. Costs can manifest in many ways, including changes in resource usage or metabolism, self-damage from inflammatory reactions, lost opportunities (e.g., foraging reproduction), and often as tradeoffs with other physiological processes. However, we do not yet fully understand the factors that influence costs of immune activation across ecological scales, nor the relationship between immune costs and protection from parasites, despite the common assumption that greater costs equates to better protection. For my dissertation, I have investigated large-scale drivers of immune costs, specifically whether life history and/or body mass influence costs of immune activation (Chapter 1), whether magnitude of parasite exposure affects immune activation costs at the population level (Chapter 2), and the relationship between costs of immune activation and benefit in terms of parasite protection (Chapter 3). Across taxa, immune costs are likely to be affected by host life history traits such as longevity and reproductive scheduling such that long-lived and slow to mature species (i.e., slow-paced) should experience lower costs than animals that die comparatively early (i.e., fast-paced). By reducing immune costs, slow-paced species could reduce the accumulation of damage associated with repeated activations of the immune response that could reduce successful reproduction over a long life. Likewise, body mass should also be an important determinant of immune costs as physical size should affect the extent to which hosts are exposed to parasites as well as their ability to combat infection. For the first chapter, I used meta-analysis to determine whether life history traits (lifespan and time to maturity) and/or body mass affected functional costs of immune activation (e.g., changes in performance, food intake, growth, mass, reproductive effort/success, survival) across taxa. The results of this study showed that, in general, animals incur costs of immune activation and that costs are influenced by life history and body mass such that species that are relatively long-lived experience greater costs of immune activation than species that are relatively short-lived. We also found that small species experienced relatively greater costs than large species. Such patterns may arise because long-lived species may have been selected to endure high costs of immune activation to develop more robust adaptive responses in order to extend lifespan. In addition, small animals may experience greater costs than large animals because of a higher cell turnover rate potentially resulting in greater self- damage (via oxidative damage). While costs of immune activation can be broadly predicted by lifespan and body mass, smaller- scale factors, such as magnitude of exposure to parasites are also likely important drivers of immune costs within populations. Indeed, if costs increase linearly with magnitude of exposure, then at a certain level of parasite burden, costs may become too great for the host and selection may favor hosts that tolerate, rather than eliminate infection. In the second chapter, I investigated how exposure to multiple concentrations of Salmonella lipopolysaccharide (LPS), a immunogenic component of Gram negative bacteria cell walls, affected immune costs in brown anole lizards (Anolis sagrei). To quantify costs, I examined allocation of leucine, a critical amino acid to immune tissue (liver) and reproductive tissue (gonads). I predicted that immune costs would increase with exposure, however, because females often suffer decrements in immune function during reproduction, I expected their immune costs to be less pronounced than males. I also hypothesized that leucine allocation to reproductive tissue would decrease with increasing magnitude of LPS exposure because immune activation often results as tradeoffs as competing physiological systems vie for limited resources. I found that costs of immune activation increased with magnitude of LPS exposure, and that costs differed between the sexes as males allocated more leucine to the liver at high LPS doses, but did not shift allocation from gonads to livers. Females, however, tended to bias resources to livers and away from gonads with increasing LPS doses. Interestingly, I also found that cost of immune activation increased linearly with magnitude of exposure, indicating that this species may tolerate high levels of infection with Salmonella bacteria as the cost of resisting infection is likely to become unmanageable. Such a finding suggests that at the population level, brown anoles may be particularly important contributors to the spread of Salmonella within populations, or even communities. Although costs of immune activation may drive a host’s response to infection by limiting the magnitude of its response when costs of a strong response are too great, we cannot predict how immune costs may be driving parasite prevalence and selection on hosts unless we understand the relationship between costs of immune activation and protection. While it is commonly assumed that high costs of immune activation are indicative of a stronger immune response and ultimately better protection for the host, the relationship between immune costs and benefits remains unstudied. In the third chapter, I examined host- and parasite-mediated costs of parasite exposure and the relationship between costs and benefits of immunity by exposing brown anole lizards to live or killed malaria parasites and following the course of infection over 7 weeks. I measured costs by quantifying glucose oxidation during the 12-36 hours following exposure to determine whether and how cost of initial exposure related to protection from malaria parasites. As glucose is the primary fuel source for malaria parasites, we predicted that hosts that oxidized little glucose would also experience lower parasite burdens. We found that lizards infected with killed parasites oxidized less glucose than control-infected animals, however lizards infected with live parasites did not differ from either the control or killed parasite group, indicating the possibility of a parasite-mediated mechanism to slow host-driven glucose sequestration. Importantly, we also found that the cost of exposure appeared to come with a benefit: lizards infected with live parasites that experienced the lowest glucose oxidation also had lower parasite burdens over the 7 weeks following exposure. The results from this study show that brown anoles that experience greater costs of malaria exposure also experience greater protection, contributing to our understanding of how individual-level processes drive disease dynamics within communities. Altogether, my dissertation has identified that broad characteristics such as life history and body mass can be helpful in predicting costs of immune activation and has additionally demonstrated the importance of smaller-scale processes such as the relationship between immune costs and magnitude of exposure at the population level and the relationship between immune costs and benefits at the individual level. These studies have expanded our understanding of the factors that drive variation in immunity at multiple levels and give the field of ecoimmunology a more holistic picture of the species, population and individual-level processes that affect host-parasite interactions within communities.

Green anoles are small lizards of the Southeastern United States. They possess an extensible throat-fan called a dewlap. Males have larger dewlaps and display them more often than females. Displays occur during courtship, during agonistic interaction, and during encounters with potential predators. The size of the dewlap of male green anoles is positively correlated with maximum bite force capacity. Bite force capacity, in turn, is predictive of the winner during agonistic interactions. The correlation between these traits suggests that dewlap size may be used as a reliable signal of maximum bite force capacity. In this dissertation, I address three components of this system. First, I manipulate dewlap size and stage interactions between male green anoles. By removing the correlation between dewlap size and bite force, I was able to show that during staged encounters, bite force is predictive of the winner, but dewlap size is not. In the second chapter, I test for potential costs due to an increased predation risk as a result of dewlap displays. I observed no difference in recapture rates between animals that were experimentally prevented from extending their dewlaps and control counterparts. However, other data suggest that the presence of a pink dewlap may increase risk of predation. These results suggest that though there may be a predation-based cost to dewlap displays, green anoles use behavioral means to ameliorate this risk. Finally, I use a castration and hormone-replacement experiment to test whether testosterone mediates seasonal changes in dewlap size and bite force. I hypothesized that testosterone would mediate changes in both traits in order to maintain the correlation between them. However, I found no effect of testosterone on change in dewlap size or bite force performance. Another trait, sprint speed performance, was affected by hormone treatment in the breeding season such that animals with high levels of testosterone ran faster than animals from the other treatment groups. My results corroborate other research showing that hormones regulate plasticity in some systems, while other systems are insensitive. However, the mechanisms that regulate changes in the two components of the reliable signaling system in green anoles remain unknown.

No description available.

The importance of abiotic influences on the strength of biotic interactions is largely unknown. To explain large annual fluctuations in the population size of the tropical lizard, Anolis limifrons, on Barro Colorado Island, Panama, I hypothesized that annual variation in lizard population size is the result of modifications in the rate of predation on lizard eggs by Solenopsis ants induced by annual variation in wet season rainfall. I tested this hypothesis by manipulating water availability on experimental plots to Simulate the wettest (HW) and driest (LW) wet seasons in the last twenty years. The mean time to find and attack eggs by Solenopsis ants was significantly shorter on HW plots (range=6.6-21.7 days) than LW plots (range=17.8-30.8 days). Exponential models that regressed time on the cumulative percent mortality indicated that 1) the rate of predation was 3-5 times faster on HW plots than LW plots and 2) the predicted mortality of lizard eggs during their 42 day incubation period was 82.2-95.7% on HW plots and 56.1-58.6% on LW plots. Thus, the amount of rainfall during the wet season affected the population size of A. limifrons by modifying the strength of the interaction between Solenopsis ants and the eggs of A. limifrons. / Master of Science

Anolis bahorucoensis males were found to possess three species-specific stereotypic displays in their repertoire, referred to as types A, B, and C, and one nonstereotypic headbob movement, the step-bob. Female A. bahorucoensis were found to use one stereotypic display pattern, analogous to the males' type A display. Anolis bahorucoensis also performed eight display modifiers, many of which were typical of the Anolis genus, including: mouth gape/tongue protrusion, gular expansion/dewlap extension, dorsal and nuchal crests, lateral compression, lateral presentation and bow. Two modifiers performed by males were unique to A. bahorucoensis: labeled as "hip-kick" and “head-swing". Use of displays and modifiers was examined for four contexts: malealone, male-male, male-resident-female, and male-strange-female. Anolis bahorucoensis type A, B, and C displays demonstrated extreme minimalization in structure (i.e. low head amplitude, high frequency twitch-nods) and signal use (i.e. low display rates, performed at short inter-lizard separation distances) which are in direct opposition to the display behavior of other anoles. Other atypical anoline characteristics of A. bahorucoensis include reduced dewlap size and infrequent dewlap extension. / Master of Science

Invasive species often encounter climatic conditions that differ significantly from those of their native range. These environmental shifts may trigger phenotypic responses, resulting through some combination of adaptation and plasticity, that enable the invader to persist under novel thermal regimes. In this dissertation, I examine phenotypic changes in a tropical lizard that has successful invaded a cooler temperate climate, specifically examining traits that may promote survival and reproduction in their new range. First, I examined physiological traits, as I predicted greater cold tolerance would be necessary to survival in the invasive range. I found that invasive populations tolerated lower temperatures, exhibited greater maximum sprint speeds, and had higher metabolic rates than native populations. Next, I examined how life-history traits may change in the invasive range in order to facilitate reproduction under shorter breeding and growing seasons. I found that compared to native females, invasive females had shorter interlaying intervals and produced eggs that hatched more quickly. Once I quantified changes physiological and life-history traits that may have aided in successful establishment, I executed a common garden study to determine whether changes were the result of adaptation or plasticity. I found that differences in critical thermal minimum, metabolic rate, interlaying interval, and incubation period were maintained in lab-reared offspring, while measures of sprint speed converged. My results provide evidence that life history and physiology can evolve rapidly during invasion. These findings are useful to understanding contemporary evolution, and also provide valuable insight on how species respond to environmental shifts, both during invasions and as a result of climate change. / Doctor of Philosophy / When species invade a new area, they often face different climates that make can make survival and reproduction challenging. In response, species may alter traits in order to adjust to new temperatures and conditions. In this dissertation, I examine trait changes in a tropical lizard that has successfully invaded a cooler temperate climate, specifically examining traits that may help them to survive and reproduce in their new range. First, I examined physiological traits, as I predicted greater cold tolerance would be necessary to survival in the invasive range. I found that invasive populations tolerated lower temperatures, could sprint faster, and had higher metabolism than native populations. Next, I examined how reproductive traits may change in the invasive range in order to facilitate reproduction under shorter breeding and growing seasons. I found that compared to native females, invasive females had less time between egg lays and produced eggs that hatched more quickly. Once I assessed how traits may have changed in the new range, I determined whether changes resulted from evolution or not. I found that differences in low temperature tolerance, metabolic rate, the time between egg lays, and incubation period were the result of evolution, while sprint speed did not seem to be the result of evolution. My results provide evidence that traits can evolve rapidly during invasion, allowing invasive species to persist and spread in new areas.