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Articles 181 - 210 of 2113

Full-Text Articles in Evolution

Three New Species Of Genus Scorpiops Peters, 1861 From Tibet, China (Scorpiones: Scorpiopidae), With Implications For The Diagnostic Values Of Qualitative Characters, Victoria Tang, Kaichen Ouyang, Zhenbang Liu, František Šťáhlavský Aug 2024

Three New Species Of Genus Scorpiops Peters, 1861 From Tibet, China (Scorpiones: Scorpiopidae), With Implications For The Diagnostic Values Of Qualitative Characters, Victoria Tang, Kaichen Ouyang, Zhenbang Liu, František Šťáhlavský

Euscorpius

Three new species of genus Scorpiops Peters, 1861 are described from Tibet Autonomous Region, China. S. deshpandei sp. n. is described based on an adult male and an immature pair collected from Mêdog County, Nyingchi, with additional molecular evidence substantiating its validity against S. longimanus Pocock, 1893. S. kovariki sp. n. is featured by a single adult female from Zayü. This species is only weakly supported by its genetic distance from S. jendeki Kovařík, 1994, but empirical understanding of the morphological variation in Scorpiops species motivated us to consider them as distinct. S. matthewi sp. n. is based on …


Euscorpius Gulhanimae Sp. N. From The Konya Province, Turkey (Scorpiones: Euscorpiidae), Ersen A. Yağmur Aug 2024

Euscorpius Gulhanimae Sp. N. From The Konya Province, Turkey (Scorpiones: Euscorpiidae), Ersen A. Yağmur

Euscorpius

A new species Euscorpius gulhanimae sp. n. is described from southern Turkey (Beyşehir District of Konya Province). It differs by trichobothrial numbers in Pv and et series; these numbers are the highest in all species of Euscorpius in Turkey. E. gulhanimae sp. n. has light greyish yellow mesosoma, dark reddish-brown chela and dark brown metasomal segments III-V; the new species is distinguished by this two-colored feature from all Euscorpius species. With this description, the known number of species in the family Euscorpiidae in Turkey is increased to 21.


Scorpions Of The Horn Of Africa (Arachnida: Scorpiones). Part Xxxiii. Three New Species Of Gint From Ethiopia And Somaliland (Buthidae), František Kovařík, Hassan Sh A. Elmi, František Šťáhlavský Aug 2024

Scorpions Of The Horn Of Africa (Arachnida: Scorpiones). Part Xxxiii. Three New Species Of Gint From Ethiopia And Somaliland (Buthidae), František Kovařík, Hassan Sh A. Elmi, František Šťáhlavský

Euscorpius

Three new species, Gint sahil sp. n. from Somaliland and Gint abshiri sp. n. and G. derbiae sp. n. from Ethiopia are described and compared with other species of the genus. Additional information is provided on the taxonomy and distribution of the genus Gint, fully complemented with color photos of specimens of the new species, as well as of their habitats. Furthermore, alongside the analyses of external morphology and hemispermatophores, we have provided description of the karyotype of G. abshiri sp. n. This species exhibits karyotype with 2n=27. Included is distribution map and a key for the genus Gint …


Revision Of The Genus Scorpio In Jordan, With A Description Of A New Genus And Three New Species (Scorpiones: Scorpionidae), Bassam Abu Afifeh, Ersen A. Yağmur, Mohammad Al–Saraireh, Zuhair Amr Aug 2024

Revision Of The Genus Scorpio In Jordan, With A Description Of A New Genus And Three New Species (Scorpiones: Scorpionidae), Bassam Abu Afifeh, Ersen A. Yağmur, Mohammad Al–Saraireh, Zuhair Amr

Euscorpius

Several new Scorpio populations are studied from various habitats in Jordan, including specimens previously identified as Scorpio kruglovi Birula, 1910 and S. fuscus (Ehrenberg, 1829). A new scorpionid genus, Jordanius gen. n. is described, mainly differentiated from the genus Scorpio Linné, 1758 by the elongation and heavy patterns of granulation of chela manus, and granulated chela fingers. Scorpio granulomanus Al-Saraireh et al., 2023 is transferred to the new genus, and Jordanius maysaraensis gen. et sp. n. is described. Also, Scorpio jordanensis sp. n. and S. wahbehi sp. n. are described. Detailed …


A Comparative Analysis Of Extant Oceanic Shark Species Using Trait-Based Ecology, Elizabeth A. Johnson Aug 2024

A Comparative Analysis Of Extant Oceanic Shark Species Using Trait-Based Ecology, Elizabeth A. Johnson

All HCAS Student Capstones, Theses, and Dissertations

Over the past few decades, scientists have been working together to mitigate human impacts on global shark populations, but deciding which species need the most immediate attention can be difficult. This study uses a newly emerging approach to ecology, trait-based ecology, to identify trends in trait expression with depth and determine which species have the most unique sets of traits. While trait-based ecology has already been applied to numerous fields, a trait-based approach to shark research is still in its infancy. A total of 15 traits across 337 oceanic shark species were examined to identify trends in trait expression and …


The Role Of Elevation In The Migration, Physiology, And Genomic Diversification Of Birds, Jessie L. Williamson Aug 2024

The Role Of Elevation In The Migration, Physiology, And Genomic Diversification Of Birds, Jessie L. Williamson

Biology ETDs

Elevational gradients cause profound eco-climatic variation across short distances. Partial pressure of oxygen (PO2) is a severe challenge that organisms face at high elevations; due partly to specialization on PO2, most Neotropical bird species have narrow elevational ranges. However, a small fraction are elevational generalists that span sea level to high elevations, and a subset undertake extreme migratory journeys from low to high elevations biannually. My dissertation combines diverse approaches across levels of biological organization to understand how elevation impacts the ecology, evolution, physiology, and migration of montane birds. I examined ‘extreme’ elevational …


Alfred Russel Wallace Notes 31. Wallace’S Personal Copy Of “Life Of Alexander Von Humboldt.”, Charles H. Smith Aug 2024

Alfred Russel Wallace Notes 31. Wallace’S Personal Copy Of “Life Of Alexander Von Humboldt.”, Charles H. Smith

Faculty/Staff Personal Papers

Alfred Russel Wallace owned a personal copy of the two-volume 1873 English edition of the Life of Alexander von Humboldt, now held by the library of the Linnean Society of London. Each volume is highly annotated, and the nature of these notes, and their several-directioned importance, is here discussed.


Venom Complexity Within Garter Snakes And The Role Of Diet In Toxin Diversification, Tucker Heptinstall Aug 2024

Venom Complexity Within Garter Snakes And The Role Of Diet In Toxin Diversification, Tucker Heptinstall

All Theses

Complex traits, such as body size and venom, are often under strong selection by

dietary ecology and can increase efficiency of prey capture and processing. To investigate relationships between ecology and trait evolution in Thamnophis, we amassed nearly 10,000 diet records for 32/35 Thamnophis species and classified each species’ dietary repertoire. We categorized 15/32 species as generalist predators and 17/32 species as specialist predators of varying prey groups and investigated the hypothesis that generalist predators have larger body size. However, we found no significant relationship between body size and dietary specialization. Venom has evolved over 100 times across the Tree …


Connecting Climate And Geography With Diversification And Conservation Of A Western North American Endemic Mammal, Sorex Monticola, Antonia Androski Jul 2024

Connecting Climate And Geography With Diversification And Conservation Of A Western North American Endemic Mammal, Sorex Monticola, Antonia Androski

Biology ETDs

Repeated glacial cycles of the Pleistocene initiated complex sequences of divergence and secondary contact with gene flow for many North American species. In my first chapter, I expand our understanding of the phylogeography of the montane shrew, Sorex monticola, with range-wide genetic sampling and geospatial analyses to reconstruct the history of clades within this species and test whether evolutionarily divergent clades occupy distinct abiotic niches. In my second chapter, I build upon these hypotheses, providing the first estimates of evolutionary relationships and timing of diversification based on genome-wide markers. In my third chapter, I use a systematic review of the …


Antimicrobials Produced By Ants: Chemical Properties And Microbe Specificity, Katy Chon Jul 2024

Antimicrobials Produced By Ants: Chemical Properties And Microbe Specificity, Katy Chon

Master's Theses

Antibiotic resistance is a growing public health concern worldwide, and for over a decade, we have been witnessing the growth of difficult to treat infectious diseases caused by bacteria that are becoming resistant to antibiotics. This resistance can be mostly related to the misusing and improper use of antibiotics in both humans and animals. To restore this problem, humans have turned to new sources for the production of antibiotics. In this study, we focused on using ants. Social insects, including ants and bees, have faced strong disease pressures during their evolution and have developed a range of methods to fight …


Populations Of The Stygobiotic Amphipod Palearcticarellus Pusillus (Martynov, 1930) Maintain Genetic Connectivity Between The Mountain Springs And The Deep Bottom Habitats Of Lake Teletskoye (Altai Mountains, Russia), Ivan Marin, Liubov Yanygina, Svetlana Ostroukhova, Dmitry Palatov Jul 2024

Populations Of The Stygobiotic Amphipod Palearcticarellus Pusillus (Martynov, 1930) Maintain Genetic Connectivity Between The Mountain Springs And The Deep Bottom Habitats Of Lake Teletskoye (Altai Mountains, Russia), Ivan Marin, Liubov Yanygina, Svetlana Ostroukhova, Dmitry Palatov

International Journal of Speleology

The diversity of underground fauna is often associated with the presence of karst areas, which have extensive underground cavities and connecting channels. Non-karst areas, however, make up a larger portion of the planet’ surface, and our understanding of the distribution and dispersal abilities of underground fauna in these areas currently remains limited. During a recent study of the diversity of stygobiotic crustaceans in the mountain streams of the Kurai Mountain Range (Altai, Russia), a small-sized species of crangonyctid amphipod, Palearcticarellus pusillus (Crustacea, Amphipoda, Crangonyctidae) was found in high-altitude springs. This species has been previously known only from deep-water habitats in …


Sexually Antagonistic Coevolution Of The Male Nuptial Gift And Female Feeding Behaviour In Decorated Crickets, Samuel Burns-Dunn, Tassie Mortys, Clarissa M. House, Christopher Mitchell, Kristin R. Duffield, Bert Foquet, Ben M. Sadd, Scott K. Sakaluk, John Hunt Jul 2024

Sexually Antagonistic Coevolution Of The Male Nuptial Gift And Female Feeding Behaviour In Decorated Crickets, Samuel Burns-Dunn, Tassie Mortys, Clarissa M. House, Christopher Mitchell, Kristin R. Duffield, Bert Foquet, Ben M. Sadd, Scott K. Sakaluk, John Hunt

Faculty Publications – Biological Sciences

The evolution of nuptial gifts has traditionally been considered a harmonious affair, providing benefits to both mating partners. There is growing evidence, however, that receiving a nuptial gift can be actively detrimental to the female. In decorated crickets (Gryllodes sigillatus), males produce a gelatinous spermatophylax that enhances sperm transfer but provides little nutritional benefit and hinders female post-copulatory mate choice. Here, we examine the sexually antagonistic coevolution of the spermatophylax and the female feeding response to this gift in G. sigillatus maintained in experimental populations with either a male-biased or female-biased adult sex ratio. After 25 generations, males …


Wildlife Conservation: The Importance Of Individual Personality Traits And Sentience, Karen A. Owens, Gosia Bryja, Marc Bekoff Jul 2024

Wildlife Conservation: The Importance Of Individual Personality Traits And Sentience, Karen A. Owens, Gosia Bryja, Marc Bekoff

Animal Sentience

Individual differences in personality types within the same species have been studied much less than differences between species and populations. Personality differences are related to risk-taking and exploration, which in turn correlate with individuals' daily responses, decisions, and fitness. Bold and shy personality types can have different advantages and disadvantages under different social or environmental pressures. Analyzing personality differences has helped clarify how elk habituate to a well-populated area and how management strategies can be adapted to them. For wolves newly repatriated to Colorado, individual personality factors are likely to prove important for adapting to their new homes as well …


The Influence Of Resource Patch Condition And Size On Social Interactions, Reproductive Behaviors, And Oviposition In A Fungivorous Beetle, Lillian J. Fornoff , '21, C. A. Stahlmann Roeder, E. D. Brodie Iii, Vincent A. Formica Jul 2024

The Influence Of Resource Patch Condition And Size On Social Interactions, Reproductive Behaviors, And Oviposition In A Fungivorous Beetle, Lillian J. Fornoff , '21, C. A. Stahlmann Roeder, E. D. Brodie Iii, Vincent A. Formica

Biology Faculty Works

Variation among resource patches can structure spatial patterns of social behavior. Individual preferences and requirements for heterogeneous resources can lead to differences in where behaviors take place and which kinds of individuals interact. In this study we examined whether properties of habitat patches predict presence of and interactions among wild forked fungus beetles (Bolitotherus cornutus). B. cornutus use shelf-like fruiting bodies of wood decaying fungi (brackets) as social arenas, courtship and mating sites, oviposition locations, and food sources. Brackets on a single log vary in size and condition and represent a dynamic resource as individual brackets decay over …


Climate And Shared Evolutionary History Drive Trait Variation Among Species Of Neotropical Understory Monocots, Eleinis Ávila-Lovera, Oscar M. Vargas, Jennifer L. Funk, Kathleen M. Kay, Gregory R. Goldsmith Jun 2024

Climate And Shared Evolutionary History Drive Trait Variation Among Species Of Neotropical Understory Monocots, Eleinis Ávila-Lovera, Oscar M. Vargas, Jennifer L. Funk, Kathleen M. Kay, Gregory R. Goldsmith

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Environmental variation commonly drives functional trait diversity within species, among species, and across communities. Climate and shared evolutionary history can both influence trait–environment relationships. We studied variation in plant functional traits among closely related Costus species occurring across environmental gradients, the extent to which this variation occurs within single species, and how that variation may be influenced by shared evolutionary history. We measured leaf, aboveground stem, rhizome, and fine root traits of 17 species of Costus in eight sites in Costa Rica and Panama, which varied in elevation, temperature, and precipitation. We then assessed the relationships among traits and environmental …


Novel Adaptations In Iron Regulation Acquired During Chronic Fungal Cf Infections, Daniel R. Murante Jun 2024

Novel Adaptations In Iron Regulation Acquired During Chronic Fungal Cf Infections, Daniel R. Murante

Dartmouth College Ph.D Dissertations

Chronic fungal infections are highly recalcitrant to treatment; we postulated that as populations persist, increasing genetic diversity is reflected in phenotypic heterogeneity, contributing to treatment inefficacies. The study of evolutionary patterns is underrepresented in chronic fungal infections, and to supplement this body of knowledge, we leveraged isolates acquired from four individuals with chronic fungal-dominated cystic fibrosis infections. We evaluated in-host evolution through a whole-genome sequencing approach, comparing multiple isolates obtained from each subject's sputum and bronchoalveolar lavage fluid. Our analysis found non-synonymous mutations that arose in parallel across the independent infections in the gene MRS4, which encodes a mitochondrial …


Isolation Of Gametophytic Selection And Selective Embryo Abortion In Mimulus Guttatus, Desmond C. Willson Jun 2024

Isolation Of Gametophytic Selection And Selective Embryo Abortion In Mimulus Guttatus, Desmond C. Willson

University Honors Theses

A lack of genomic studies examining gametophytic selection (GS) and selective embryo abortion (SEA)--which occur during the reproduction of angiosperms--leaves questions regarding the adaptive and evolutionary effects of these processes. Analyzing deviations from Mendelian segregation offers an avenue for identifying loci targeted by GS and SEA, and their contributions to purging of genetic load. However, other selective processes such as meiotic drive and cytonuclear interactions, as well as pollen and ovule abortion, can cause distortion. To distinguish the effects of GS and SEA from other causes of distortion, we will perform reciprocal crosses between highly homozygous and highly heterozygous individuals …


The Polyaneuploid Cancer Cell State And Therapeutic Resistance: Eco-Evolutionary Dynamics In Structured Populations, Anuraag Bukkuri Jun 2024

The Polyaneuploid Cancer Cell State And Therapeutic Resistance: Eco-Evolutionary Dynamics In Structured Populations, Anuraag Bukkuri

USF Tampa Graduate Theses and Dissertations

In this dissertation, I develop and apply eco-evolutionary modeling techniques to understand how the polyaneuploid cancer cell (PACC) state, entered when aneuploid cells exit the cell cycle after S phase and undergo a whole genome duplication, contributes to therapeutic resistance. Since resistance remains one of the primary causes of treatment failure in cancer patients, it is critical to understand how such demographic state transitions allow for acclimatization of cancer cells to therapeutic stressors and how they interact with evolutionary processes to promote irreversible resistance.

In Chapters Two and Three, I lay the foundation for this work. In Chapter Two, I …


Rewiring The Sex-Determination Pathway During The Evolution Of Self-Fertility., Yongquan Shen, Shin-Yi Lin, Jonathan Harbin, Richa Amin, Allison Vassalotti, Joseph Romanowski, Emily Schmidt, Alexis Tierney, Ronald E Ellis Jun 2024

Rewiring The Sex-Determination Pathway During The Evolution Of Self-Fertility., Yongquan Shen, Shin-Yi Lin, Jonathan Harbin, Richa Amin, Allison Vassalotti, Joseph Romanowski, Emily Schmidt, Alexis Tierney, Ronald E Ellis

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Although evolution is driven by changes in how regulatory pathways control development, we know little about the molecular details underlying these transitions. The TRA-2 domain that mediates contact with TRA-1 is conserved in Caenorhabditis. By comparing the interaction of these proteins in two species, we identified a striking change in how sexual development is controlled. Identical mutations in this domain promote oogenesis in Caenorhabditis elegans but promote spermatogenesis in Caenorhabditis briggsae. Furthermore, the effects of these mutations involve the male-promoting gene fem-3 in C. elegans but are independent of fem-3 in C. briggsae. Finally, reciprocal mutations in these genes show …


Evolution And Adaptation To Temperature In Thermotogota, Anne Amelia Farrell Jun 2024

Evolution And Adaptation To Temperature In Thermotogota, Anne Amelia Farrell

Dartmouth College Ph.D Dissertations

Life thrives across incredibly diverse environmental conditions, yet most organisms are restricted to growing within a narrow range around their optimum growth temperature (OGT). The evolutionary events leading to changes in OGT are poorly understood, and it is uncertain if specific genes are required to thrive at a particular temperature. The bacterial phylum Thermotogota is an excellent model for the evolution of OGT. It comprises mesophilic, thermophilic, and hyperthermophilic members that collectively grow between 20°C and 90°C.

In this work, I analyze the history of OGT in the Thermotogota phylum and show how horizontal gene transfer contributes to the evolution …


Multi-Type Branching Processes In Time-Varying Environments, Arash Jamshidpey May 2024

Multi-Type Branching Processes In Time-Varying Environments, Arash Jamshidpey

Biology and Medicine Through Mathematics Conference

No abstract provided.


A New Case Of Pedipalp Regeneration In Scorpio Kruglovi Birula, 1910 (Scorpiones: Scorpionidae), Ersen A. Yağmur, Mehmet S. Kılıç, Eyüp Güneş May 2024

A New Case Of Pedipalp Regeneration In Scorpio Kruglovi Birula, 1910 (Scorpiones: Scorpionidae), Ersen A. Yağmur, Mehmet S. Kılıç, Eyüp Güneş

Euscorpius

A new case of pedipalp regeneration is described and illustrated in a subadult female of Scorpio kruglovi Birula, 1910. A small, regenerated part of chela is observed on the anterior aspect of a normally developed right patella. This is the second published case of pedipalp regeneration.


Omani Camels From A Cultural And Genomics Perspective, Al Muatasim Al Zadjali May 2024

Omani Camels From A Cultural And Genomics Perspective, Al Muatasim Al Zadjali

Electronic Theses and Dissertations

The Dromedarian camel, Camelus dromedarius, is native to the Arabian Peninsula, including the Sultanate of Oman. These camels are used for food, milk, as well as show and racing competitions. Despite their economic and cultural importance research on camels in Oman is limited. The goal of this study was to examine their genomic variation, relationship with camels in other parts of the Arabian Peninsula, and to determine if selective breeding has led to the establishment of distinct breeds in Oman. Information was compiled from multiple sources to produce a comprehensive review on the breeding, management, economic and cultural use, …


Comparative Functional And Computational Analyses Of Primate Seminal Proteins: Insights Into Sexual Selection And Hiv/Siv, Emine Feride Kahveci May 2024

Comparative Functional And Computational Analyses Of Primate Seminal Proteins: Insights Into Sexual Selection And Hiv/Siv, Emine Feride Kahveci

Electronic Theses and Dissertations

Male reproductive protein-coding genes are among the most rapidly evolving genes across many animal taxa, commonly attributed to sexual selection; however, pathogen defense mechanisms might also be contributing factors. This study aimed to both computationally and experimentally investigate the selective pressures responsible for the rapid evolution of seminal proteins. In the first part, the research focused on sexual selection in the form of post-copulatory sperm competition as a driving force behind the evolution of kallikrein related peptidase 3 (KLK3), also known as prostate-specific antigen (PSA), a key prostatic seminal protein. KLK3 is responsible for the liquefaction of semen coagulum through …


Unraveling The Paradox Of The 'Great Speciators': Evolutionary Dynamics Of A Geographic Radiation Of Island Kingfishers (Todiramphus), Jenna Merle Mccullough May 2024

Unraveling The Paradox Of The 'Great Speciators': Evolutionary Dynamics Of A Geographic Radiation Of Island Kingfishers (Todiramphus), Jenna Merle Mccullough

Biology ETDs

The paradox of the ‘Great Speciators’ describes a biogeographic pattern in which geographically widespread lineages have strong overwater dispersal capabilities, yet exhibit genetic and phenotypic divergence between islands, suggesting limited dispersal and cessation of gene flow. In my dissertation, I leveraged whole genomes and two comprehensive trait datasets of dispersal ability and plumage coloration of all described diversity within Todiramphus kingfishers, a rapid radiation of largely island endemic ‘Great Speciators.’ Chapter 1 reveals that whole genome datasets do not outright solve the evolutionary relationships of this clade and that widespread incomplete lineage sorting (ILS) and gene flow are sources of …


Bioinformatic Comparison And Salinity Tolerance Of Various Cyanobacterial Strains, Lucie Rowe May 2024

Bioinformatic Comparison And Salinity Tolerance Of Various Cyanobacterial Strains, Lucie Rowe

Honors Theses

Cyanobacteria are an abundant and diverse group of photosynthetic prokaryotes with a long evolutionary history, which presents challenges for comprehensive taxonomic classification. Phylogenies were traditionally constructed based on the highly conserved 16S rRNA gene, but research has increasingly relied upon whole genome sequencing to elucidate evolutionary relationships, despite increased cost and time. In this thesis, publicly available genome sequences of various cyanobacterial strains were utilized to determine if the whole rRNA region, which includes the 16S, 23S, and 5S genes as well as the spacer regions between, could provide accurate, yet cost/time efficient representations of their evolutionary relationships. From phylogenetic …


Crossing The Ocean: The Importance Of Gene Flow In Island Evolution, Ethan F. Gyllenhaal May 2024

Crossing The Ocean: The Importance Of Gene Flow In Island Evolution, Ethan F. Gyllenhaal

Biology ETDs

Islands have long been a critical arena for the development of ecological and evolutionary theory, particular due to persistent open-water gaps between them. In this dissertation I demonstrates how these caps are permeable, which can be leveraged to understand evolution on islands and more broadly. The first chapter develops this connection between ongoing, overwater gene flow and island biogeographic theory, and tests it on an archipelago species. The second take a three-pronged approach in demonstrating how over-water gene flow can bias phylogenetic inference, and how many phylogeographic metrics in islands are likely shaped by long-term gene flow. The final two …


New Records Of Mesobuthus Rakhshanii Barahoei, 2022 In Iran (Scorpiones: Buthidae), Ersen A. Yağmur, Zhale Baghernavesi, Zahra Taherkhani, Parsa Akbari, Mohammad Moradi May 2024

New Records Of Mesobuthus Rakhshanii Barahoei, 2022 In Iran (Scorpiones: Buthidae), Ersen A. Yağmur, Zhale Baghernavesi, Zahra Taherkhani, Parsa Akbari, Mohammad Moradi

Euscorpius

Mesobuthus rakhshanii Barahoei, 2022 (Scorpiones: Buthidae) was so far known only from the type locality in Sistan and Baluchestan Province, Iran. We give a list of numerous new records of this species from the same province. A map and detailed illustrations are provided.


Random-Effects Substitution Models For Phylogenetics Via Scalable Gradient Approximations, A. F. Magee, A. J. Holbrook, J. E. Pekar, Itzue W. Caviedes-Solis, F. A. Matsen Iv, G. Baele, J. O. Wertheim, X. Ji, P. Lemey, M. A. Suchard May 2024

Random-Effects Substitution Models For Phylogenetics Via Scalable Gradient Approximations, A. F. Magee, A. J. Holbrook, J. E. Pekar, Itzue W. Caviedes-Solis, F. A. Matsen Iv, G. Baele, J. O. Wertheim, X. Ji, P. Lemey, M. A. Suchard

Biology Faculty Works

Phylogenetic and discrete-trait evolutionary inference depend heavily on an appropriate characterization of the underlying character substitution process. In this paper, we present random-effects substitution models that extend common continuous-time Markov chain models into a richer class of processes capable of capturing a wider variety of substitution dynamics. As these random-effects substitution models often require many more parameters than their usual counterparts, inference can be both statistically and computationally challenging. Thus, we also propose an efficient approach to compute an approximation to the gradient of the data likelihood with respect to all unknown substitution model parameters. We demonstrate that this approximate …


Connecting Genotype And Phenotype: Investigating The Functional Morphology And Molecular Architecture That Influences Craniofacial Divergence Using Lake Malawi Cichlid Fishes, Leah Delorenzo May 2024

Connecting Genotype And Phenotype: Investigating The Functional Morphology And Molecular Architecture That Influences Craniofacial Divergence Using Lake Malawi Cichlid Fishes, Leah Delorenzo

All Dissertations

Connecting genotype and phenotype to better understand how species evolve has been a goal of evolutionary developmental biologists over the last 50 years. This dissertation aims to connect genotype and phenotype of the craniofacial skeleton within the adaptive radiation of Lake Malawi cichlids to fortify our understanding of the functional, genetic, and epigenetic factors that contribute to craniofacial divergence. I start with a functional approach using 2D geometric morphometrics to assess craniofacial shape across the Lake Malawi cichlid radiation to bolster our knowledge of the bone phenotypes that are important to niche specialization and are functionally relevant. Next, I use …