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Bayesian Biogeographical Analyses with Beast: Assessment Using Simulated Data

Description
Biogeography is the study of the spatial distribution of the earth's biota, both in the present and the past. Traditionally, biogeographical studies have relied on a combination of surveys of existing populations, fossil evidence, and the geological record of the earth. However, with the advent of relatively inexpensive methods of…

Biogeography is the study of the spatial distribution of the earth's biota, both in the present and the past. Traditionally, biogeographical studies have relied on a combination of surveys of existing populations, fossil evidence, and the geological record of the earth. However, with the advent of relatively inexpensive methods of DNA sequencing, it is now possible to use information concerning the genetic relatedness of individuals in populations to address questions about how those populations came to be where they are today. For example, biogeographical studies of HIV-I provide strong support for the hypothesis that this virus arose in Africa through a host switch from chimpanzees to humans and only began to spread to human populations located on other continents some 60 to 70 years ago (Sharp & Hahn, 2010).
ContributorsZheng, Wenyu (Author) / Taylor, Jesse (Thesis director) / Escalante, Ananias (Committee member) / Thieme, Horst (Committee member) / Barrett, The Honors College (Contributor)
Created2015-05
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A survey of cancer prevalence within birds (the clave Aves).

Description
Cancer is a disease that occurs in many and perhaps all multicellular organisms. Current research is looking at how different life history characteristics among species could influence cancer rates. Because somatic maintenance is an important component of a species' life history, we hypothesize the same ecological forces shaping the life…

Cancer is a disease that occurs in many and perhaps all multicellular organisms. Current research is looking at how different life history characteristics among species could influence cancer rates. Because somatic maintenance is an important component of a species' life history, we hypothesize the same ecological forces shaping the life history of a species should also determine its cancer susceptibility. By looking at varying life histories, potential evolutionary trends could be used to explain differing cancer rates. Life history theory could be an important framework for understanding cancer vulnerabilities with different trade-offs between life history traits and cancer defenses. Birds have diverse life history strategies that could explain differences in cancer suppression. Peto's paradox is the observation that cancer rates do not typically increase with body size and longevity despite an increased number of cell divisions over the animal's lifetime that ought to be carcinogenic. Here we show how Peto’s paradox is negatively correlated for cancer within the clade, Aves. That is, larger, long-lived birds get more cancer than smaller, short-lived birds (p=0.0001; r2= 0.024). Sexual dimorphism in both plumage color and size differ among Aves species. We hypothesized that this could lead to a difference in cancer rates due to the amount of time and energy sexual dimorphism takes away from somatic maintenance. We tested for an association between a variety of life history traits and cancer, including reproductive potential, growth rate, incubation, mating systems, and sexual dimorphism in both color and size. We found male birds get less cancer than female birds (9.8% vs. 11.1%, p=0.0058).
ContributorsDolan, Jordyn Nicole (Author) / Maley, Carlo (Thesis director) / Harris, Valerie (Committee member) / Boddy, Amy (Committee member) / School of Molecular Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
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Evolution of multigene families and single copy genes in Plasmodium spp

Description
The complex life cycle and widespread range of infection of Plasmodium parasites, the causal agent of malaria in humans, makes them the perfect organism for the study of various evolutionary mechanisms. In particular, multigene families are considered one of the main sources for genome adaptability and innovation. Within Plasmodium, numerous…

The complex life cycle and widespread range of infection of Plasmodium parasites, the causal agent of malaria in humans, makes them the perfect organism for the study of various evolutionary mechanisms. In particular, multigene families are considered one of the main sources for genome adaptability and innovation. Within Plasmodium, numerous species- and clade-specific multigene families have major functions in the development and maintenance of infection. Nonetheless, while the evolutionary mechanisms predominant on many species- and clade-specific multigene families have been previously studied, there are far less studies dedicated to analyzing genus common multigene families (GCMFs). I studied the patterns of natural selection and recombination in 90 GCMFs with diverse numbers of gene gain/loss events. I found that the majority of GCMFs are formed by duplications events that predate speciation of mammal Plasmodium species, with many paralogs being neutrally maintained thereafter. In general, multigene families involved in immune evasion and host cell invasion commonly showed signs of positive selection and species-specific gain/loss events; particularly, on Plasmodium species is the simian and rodent clades. A particular multigene family: the merozoite surface protein-7 (msp7) family, is found in all Plasmodium species and has functions related to the erythrocyte invasion. Within Plasmodium vivax, differences in the number of paralogs in this multigene family has been previously explained, at least in part, as potential adaptations to the human host. To investigate this I studied msp7 orthologs in closely related non-human primate parasites where homology was evident. I also estimated paralogs’ evolutionary history and genetic polymorphism. The emerging patterns where compared with those of Plasmodium falciparum. I found that the evolution of the msp7 multigene family is consistent with a Birth-and-Death model where duplications, pseudogenization and gene lost events are common. In order to study additional aspects in the evolution of Plasmodium, I evaluated the trends of long term and short term evolution and the putative effects of vertebrate- host’s immune pressure of gametocytes across various Plasmodium species. Gametocytes, represent the only sexual stage within the Plasmodium life cycle, and are also the transition stages from the vertebrate to the mosquito vector. I found that, while male and female gametocytes showed different levels of immunogenicity, signs of positive selection were not entirely related to the location and presence of immune epitope regions. Overall, these studies further highlight the complex evolutionary patterns observed in Plasmodium.
ContributorsCastillo Siri, Andreina I (Author) / Rosenberg, Michael (Thesis advisor) / Escalante, Ananias (Committee member) / Taylor, Jesse (Committee member) / Collins, James (Committee member) / Arizona State University (Publisher)
Created2016
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A Multivariate Analysis of Life History Traits Across Species and Their Statistical Power to Predict Cancer Prevalence

Description

Cancer rates vary between people, between cultures, and between tissue types, driven by clinically relevant distinctions in the risk factors that lead to different cancer types. Despite the importance of cancer location in human health, little is known about tissue-specific cancers in non-human animals. We can gain significant insight into…

Cancer rates vary between people, between cultures, and between tissue types, driven by clinically relevant distinctions in the risk factors that lead to different cancer types. Despite the importance of cancer location in human health, little is known about tissue-specific cancers in non-human animals. We can gain significant insight into how evolutionary history has shaped mechanisms of cancer suppression by examining how life history traits impact cancer susceptibility across species. Here, we perform multi-level analysis to test how species-level life history strategies are associated with differences in neoplasia prevalence, and apply this to mammary neoplasia within mammals. We propose that the same patterns of cancer prevalence that have been reported across species will be maintained at the tissue-specific level. We used a combination of factor analysis and phylogenetic regression on 13 life history traits across 90 mammalian species to determine the correlation between a life history trait and how it relates to mammary neoplasia prevalence. The factor analysis presented ways to calculate quantifiable underlying factors that contribute to covariance of entangled life history variables. A greater risk of mammary neoplasia was found to be correlated most significantly with shorter gestation length. With this analysis, a framework is provided for how different life history modalities can influence cancer vulnerability. Additionally, statistical methods developed for this project present a framework for future comparative oncology studies and have the potential for many diverse applications.
ContributorsFox, Morgan Shane (Author) / Maley, Carlo C. (Thesis director) / Boddy, Amy (Committee member) / Compton, Zachary (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / School of Molecular Sciences (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05

Trends in Tissue-Specific Cancers

Description
A big part of understanding cancer is understanding the cellular environment itthrives in by analyzing it from a microecological perspective. Humans and other species are affected by different cancer types, and this highlights the notion that there may be a correlation between specific tissues and neoplasia prevalence. Research shows that humans are the…

A big part of understanding cancer is understanding the cellular environment itthrives in by analyzing it from a microecological perspective. Humans and other species are affected by different cancer types, and this highlights the notion that there may be a correlation between specific tissues and neoplasia prevalence. Research shows that humans are the most susceptible to adenocarcinomas and carcinomas which include the following tissues: lungs, breast, prostate, and pancreas. Furthermore, research shows that adenocarcinoma accounts for 38.5% of all lung cancer cases, 20% of small cell carcinomas, and 2.9% of large cell carcinoma. The incidence of the most common cancer types in humans is consistently increasing annually. This study analyzes trends of tissue-specific cancers across species to examine possible contributors to vulnerability to cancer. I predicted that adenocarcinomas would be the most prevalent cancer type across the tree of life. To test this hypothesis, I reviewed over 130 species that reported equal to or greater than 50 individual necropsy pathology records across 4 classes (Mammalia, amphibia, Reptilia, Aves) and ranked them by neoplasia prevalence. This information was then organized in tables in descending order. The study’s resulting tables and data concluded that the hypothesis was correct. I found that across all species adenocarcinomas were the most common cancer type and account for 30.4% of malignancies reported among species. Future research should investigate how organ size contributes to neoplasia prevalence.
ContributorsPERAZA, ASHLEY (Author) / Maley, Carlo (Thesis advisor) / Boddy, Amy (Thesis advisor) / Baciu, Cristina (Committee member) / Arizona State University (Publisher)
Created2022
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A Life History Model of Mammary Neoplasia Across Mammals

Description
Cancer rates vary significantly across tissue type and location in humans, driven by clinically relevant distinctions in the risk factors that lead to different cancer types. Despite the importance of cancer location in human health, little is known about tissue-specific cancers in non-human animals. A comparison of cancer prevalence across…

Cancer rates vary significantly across tissue type and location in humans, driven by clinically relevant distinctions in the risk factors that lead to different cancer types. Despite the importance of cancer location in human health, little is known about tissue-specific cancers in non-human animals. A comparison of cancer prevalence across the tree of life can give insight into how evolutionary history has shaped various mechanisms of cancer suppression. Here, we explore whether species-level life history strategies are associated with differences in mammary neoplasia rates across mammals. We propose that the same patterns of cancer prevalence that have been reported across species will be maintained at the tissue-specific level. We used a phylogenetic regression on 15 life history traits across 112 mammalian species to determine the correlation between a life history trait and how it relates to mammary neoplasia prevalence. A greater risk of mammary neoplasia was found in the characteristics associated with fast life history organisms and a lower risk of mammary neoplasia was found in the characteristics associated with slow life history organisms. With this analysis, a framework is provided for how different life history modalities can influence cancer vulnerability.
ContributorsMajhail, Komal Kaur (Co-author) / Majhail, Komal (Co-author) / Maley, Carlo (Thesis director) / Boddy, Amy (Committee member) / Compton, Zachary (Committee member) / College of Health Solutions (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
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Reproductive Cancer Prevalence Across Mammalian Species

Description

Cancers of the reproductive tissues make up a significant portion of the cancer burden and mortality experienced by humans. Humans experience several proximal causative carcinogens that explain a portion of cancer risk, but an evolutionary viewpoint can provide a unique lens into the ultimate causes of reproductive cancer vulnerabilities. A…

Cancers of the reproductive tissues make up a significant portion of the cancer burden and mortality experienced by humans. Humans experience several proximal causative carcinogens that explain a portion of cancer risk, but an evolutionary viewpoint can provide a unique lens into the ultimate causes of reproductive cancer vulnerabilities. A life history framework allows us to make predictions on cancer prevalence based on a species’ tempo of reproduction. Moreover, certain variations in the susceptibility and prevalence of cancer may emerge due to evolutionary trade-offs between reproduction and somatic maintenance. For example, such trade-offs could involve the demand for rapid proliferation of cells in reproductive tissues that arises with reproductive events. In this study, I compiled reproductive cancer prevalence for 158 mammalian species and modeled the predictive power of 13 life history traits on the patterns of cancer prevalence we observed, such as Peto’s Paradox or slow-fast life history strategies. We predicted that fast-life history strategists will exhibit higher neoplasia prevalence risk due to reproductive trade-offs. Furthering this analytical framework can aid in predicting cancer rates and stratifying cancer risk across the tree of life.
ContributorsDarapu, Harshini (Author) / Maley, Carlo (Thesis director) / Boddy, Amy (Committee member) / Compton, Zachary (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2022-05