Biological Sciences Honors Theses

Permanent URI for this collection


Recent Submissions

Now showing 1 - 20 of 55
  • Item
    Expressions of students’ disagreement in life sciences teambased online discussions
    Menon, Priyanka (2023-01-11)
    Studying disagreement in STEM classrooms is one way to better understand students’ sense of belonging in a learning environment by linking the frequency of disagreement with how comfortable they are contributing their true opinions. I determined whether students’ frequency of expression of disagreement in an online STEM course is affected by group composition (gender, size, topic). Disagreement is measured in this study directly by quantifying how many students replied to prompted discussion questions with disagreement statements or when students ask and answer questions to clarify the disagreement. I predicted that students would express more disagreement when they were male, were in groups with less than four people, and discussed topics involving evolutionary processes and phylogeny based on conclusions from previous literature. The results showed that there was not a difference in disagreement rate across gender, there was more disagreement for "Population Genetics" and "Other Evolutionary Processes" compared to "Phylogenetics" and "Biodiversity," and there tended to be more disagreement for teams of five compared to smaller sized groups. These findings can be applied to future biology education research to improve the ways group activities are structured to be more inclusive of students of all backgrounds and to maximize true expression of opinions.
  • Item
    The Role of Trehalase in Phenotypic Plasticity of the Buckeye Butterfly (Junonia coenia)
    Pires, Samantha (2023-01-11)
    The buckeye butterfly, Junonia coenia, shows seasonal variation in wing coloration. The duplicate genes treh-1a and treh-1b encoding a soluble form of trehalase are implicated in this environmentally induced phenotypic variation. treh-1a has been shown to be involved in the mechanism of ommochrome pigmentation plasticity in J. coenia but the role of treh-1b is unknown. In this study, I first aimed to characterize the role of treh-1b, a presumptive metabolic pathway enzyme, in both ommochrome pigmentation, and, second, to assess the potential adaptive role of trehalase upregulation in cold tolerance. CRISPR mutagenesis of the treh-1b promoter, as well as the coding region, revealed various developmental phenotypes, but had no obvious effect on ommochrome pigmentation. I next used chill coma recovery time bioassays to ask how treh-1a -associated phenotypes affect cold tolerance. My bioassays revealed that Red line butterflies (red phenotype treh-1a allele) recover from cold-shock faster than Nijh line butterflies (tan phenotype treh-1a allele) when both groups come from a warm environment, but not when both groups come from a dark, cooler environment. Interestingly, both Nijh and Red butterflies show a large reduction in recovery times when coming from a dark, cooler environment. This suggests that Red butterflies may have increased thermal retention compared to Nijh butterflies, thus allowing them to recover from cold-shock faster than Nijh butterflies. This also suggests acclimation to cooler, darker conditions impacts J. coenia recovery after cold-shock.
  • Item
    The role of araucan in nymphalid wing color pattern formation
    Siegel, Kate (2022-11-17)
    Despite the great beauty and diversity of butterfly wing color patterns, there is still much that remains unknown about how these color patterns are determined. Certain master regulator genes are known that can determine the scale type or pigment across a variety of color pattern elements, and their expression is determined through the combined activity of upstream pre-patterning genes. For one such key gene, optix, most of its regulatory network is still unknown, though candidates have been proposed. This study aims to take a closer look at the functions of one candidate upstream gene, araucan, a proximally expressed transcription factor that plays a role in wing vein specification in Drosophila. Using CRISPR-Cas9 gene editing, mutations were induced in the araucan gene in two nymphalid butterfly lineages, Junonia coenia and two co-mimetic species of Heliconius. Examining wings for phenotypes revealed some optix-typical mutations such as bright blue structural iridescence across J. coenia wings, as well as vein reductions in H. erato that suggest the function of araucan may be partially conserved relative to Drosophila. An unexpected novel phenotype affecting the iridescence of the eyespot center, or focus, also appeared, introducing a potential role for araucan in eyespot color patterning.
  • Item
    The Putrescine Puzzle: How do Manduca sexta hawkmoths respond to scented nectar in Datura wrightii flowers?
    Cheng, Sheri (2022-05)
    The unusual large amounts of a polyamine, putrescine, in the nectar of the Datura wrightii flower add complexity to the mutualistic interactions between the flower and its pollinator, Manduca sexta, acting as a potential modulator in the pollinator’s foraging behavior. However, whether this non-sugar metabolite acts as an attractant or a repellent in the floral nectar is not well understood. I performed an innate preference bioassay using the Datura nectar and a synthetic sugar solution to analyze the possible effects of putrescine on Manduca preference during foraging. Based on the assessment of the animal’s first choice, the frequency of visits per flower, and the final volume of nectar consumption measurements, this study failed to find any statistically significant difference in the moth’s preference between Datura nectar and the synthetic sugar solution. However, while the absence of behavioral changes may suggest the animal’s indifference towards the additional polyamines in the nectar, it remains possible that physiological or fecundity implications may arise from a long-term study.
  • Item
    Blue vs. Yellow Color Preference of Hyles Hawkmoths in Foraging Visitations ofVarious Real and Artificial Flowers
    Palmadessa, Matthew (2022-05)
    As one of the most important pollinators across North America, there is much incentive to further understand the foraging habits of Hyles hawkmoths. Recent research on the subspecies Hyles lineata has identified a preference for both blue and yellow colored light for flower visitations, with the stronger bias between the two being for blue. However, the blue LED used in this earlier experiment was later discovered to be more intense than the yellow, casting doubt upon this finding. Here, the idea of the former study was revisited, and a binary choice assay was created with these same two blue and yellow LEDs. However, a plastic filter was positioned below the blue one, such that its intensity was decreased to match the yellow. H. lineata moths were reared from eggs, and adults were individually released into a darkened flight chamber where each light projected its color down onto either a white Oenothera flower or false paper flower. Their first visitation was recorded as their preference. Additional testing without the filter was also conducted, as well as paper flower trials with the addition of fragrant Bergamot oil. When light intensities were equalized, the moths actually preferred yellow flowers to blue ones. However, when the filter was removed, a blue preference only reappeared for the moths tested with real flowers. This persistent yellow bias was also maintained through testing with paper flowers and Bergamot oil. Further investigations may identify whether fragrance plays a notable role in the flower color bias of H. lineata.
  • Item
    Assessing Differences in Desiccation Tolerance in Two Species of Hawaiian Swordtail Cricket
    Lam, Vincent (2022-05)
    Two species of Hawaiian swordtail cricket, L. orientalis and L. makaio, inhabit different locations on the island of Maui in the Hawaiian archipelago, generally with L. orientalis residing in a region of higher, and L. makaio inhabiting a region of lower, rainfall. This difference in habitation exposes the two species to different levels of humidity, with L. orientalis being subjected to greater levels of moisture than L. makaio, when controlling for elevation. It may be possible that these species’ distinct habitats are a result of different humidity preferences. These distributions in turn may be influenced by the different compositions of cuticular hydrocarbons (CHCs) that coat the surface of their bodies and prevent desiccation. To test whether such differences in desiccation resistance may exist, individuals from each species were subjected to a series of desiccation tolerance experiments, which measured the length of time in which each species could survive arid conditions. Additionally, the CHC profiles of each species were analyzed by extracting the CHCs from individuals of each species and running them through gas chromatography. The results of these experiments do not reveal a statistically significant difference in the survivability of L. orientalis and L. makaio in arid environments, though a difference in CHC profiles has been observed.
  • Item
    Investigation of potassium tetraborate resistance in Dickeya spp.
    Lou, Alice (2022-05)
    Dickeya spp. are common plant pathogens associated with bacterial soft rot, potato blackleg, and slow wilt, which are plant diseases that account for major losses in the agricultural industry. The diseases caused by these bacterial species are not yet fully managed with existing techniques, and new approaches need to be considered to minimize future crop loss. Previous research has shown that the inorganic salt potassium tetraborate tetrahydrate (PTB) can inhibit the growth of Dickeya species; however, disk diffusion assays result in a unique phenotype with two zones of inhibition. In this study, I investigated the effects of PTB on the growth of four Dickeya spp. I hypothesized that the production of phage is responsible for the two zones of inhibition. I used disk diffusion assays and growth curves to confirm the impact of PTB on Dickeya and attempted to directly isolate phage from the strains. To determine the mechanism of action of PTB, I used Tn-Seq libraries to determine which genes are required for growth in the presence of PTB. Tn-Seq libraries showed that different Dickeya strains shared seven overlapping genes including stress-related genes that increase bacterial resistance to PTB. I used gene expression studies to determine the changes in gene expression that result from PTB exposure. Preliminary results showed that exposure to PTB induces the expression of stress-related genes in Dickeya to increase survival in the presence of the compound. Further research is needed to better understand the implications of observed changes in bacterial gene expression.
  • Item
    A Review of Serotonin’s Role in Depression and Modern Perspectives
    McLaughlin, Liam (2022-05)
    Major depressive disorder (MDD) is a highly prevalent and debilitating illness in the modern world. In the 1960s, the theory that low serotonin (5-HT) was a primary cause of MDD emerged due to the efficacy of 5-HT restoring drugs in treating depression. The 5-HT deficiency hypothesis of depression has since been criticized through studies not being able to directly tie low serotonin to MDD. The discovery of the antidepressant efficacy of the glutamatergic stimulant ketamine led to a reevaluation of depression pathophysiology. Modern perspectives view depression as an issue of disrupted neurocircuitry resulting from stress induced atrophy of certain limbic and cortical brain regions, such as the hippocampus and PFC, and hypertrophy in the fear evaluating amygdala, the reward evaluating nucleus accumbens, and the orbitofrontal cortex. Depression may be treated by potentiating neuroplasticity, that when combined with psychotherapy, helps individuals relearn negative emotional associations and restores dysfunctional neurocircuitry. The functioning of the serotonergic system may be viewed as a vulnerability factor in developing depression due to its involvement in stress, as well as a treatment target which indirectly primes neuroplasticity. Other neurotransmitter systems similarly represent depressive risk factors and antidepressant targets, namely the noradrenergic and dopaminergic systems. Serotonergic antidepressants such as SSRIs see high rates of prescription due to their minimal side effects. They demonstrate slower efficacy than ketamine, whose dissociative side effects and potential for abuse are unideal, demanding further research of its mechanism to find safer and more effective antidepressant targets.
  • Item
    Studying Arbuscular Mycorrhizal Fungi, Their Endosymbiotic Bacteria, and Their Spores: Challenges and Solutions
    Tzng, Eileen (2022-05)
    Arbuscular mycorrhizal fungi (AMF) have broad applications in agriculture and land restoration due to their significance in forming symbiotic relationships with most terrestrial plants. However, the field of AMF is understudied, often extending results from a handful of AMF species to all AMF. Spores are a highly significant but often overlooked aspect of the AMF life cycle. In this honors thesis, I summarize the current knowledge surrounding the significance of spores in the AMF life cycle. Great strides have been made in understanding AMF spore germination, dormancy, and life strategies, but there are also gaps in the knowledge that, if filled, would further advance the various applications and studies of AMF. In particular, past research done on AMF must be revisited in order to: (1) redefine terms and standardize experiments; (2) reinforce genetic work in AMF; and (3) use knowledge from plant and seed experiments to better inform AMF experiments. I then empirically demonstrate that the endobacterium ‘Candidatus Moeniiplasma glomeromycotorum’ can be lost or gained during serial culturing practices, although the mechanisms by which endobacteria are lost or gained. I also show that routine spore processing methods, such as sonication and chemical washes during surface decontamination, can be detrimental to spore survival in some species, and therefore the interpretation of spore viability studies should be carefully considered.
  • Item
    The Distribution of Autophagosomes is Altered by the Phospholipase A2 Inhibitor ONO-RS-082
    Jovel, Caroline (2022-01)
    When cells are starved of essential nutrients, autophagy, a process of self-digestion, is induced for cell survival. Previous studies in mammalian cells have shown that a structurally intact Golgi complex negatively regulates the induction of autophagy. Other studies from the Brown lab have shown that the architectural integrity of the Golgi complex requires the activity of cytoplasmic Phospholipase A2 (PLA2) enzymes. For example, inhibitors of PLA2 enzymes cause the intact Golgi complex to fragment into “mini-stacks.” To further investigate the relationship between autophagy induction and Golgi architecture, HeLa cells were treated with the PLA2 inhibitor ONO-RS-082 (ONO) to disrupt the Golgi, and its effect on autophagy was visualized by imaging the association of the autophagosome marker protein LC3. Normally, LC3-labeled nascent autophagosomes are evenly dispersed throughout the cytoplasm; however, I found that treatment with ONO caused autophagosomes to cluster in the center of the cell. This clustering occurred in both a time- and concentration-dependent manner. This result reveals a previously unknown connection between autophagy and the Golgi complex.
  • Item
    The Metal Requirements of Bacillus subtilis
    Remick, Kaleigh (2021-12)
    Metal ions are essential for many biological processes across all domains of life. In Bacillus subtilis, they function as essential cofactors for enzymes, a component of biosensors for oxidative damage, in the assembly of the ribosome, in the folding of mRNA, and a myriad of other processes. In Bacillus subtilis, the minimum metal quota per cell to sustain growth has not previously been established. In this study, we establish a metal-limited minimal medium that enables us to probe the interaction of metals at the thresholds for growth and determine how the cell responds to limitation. Here we determine the minimum concentrations of magnesium, iron, and manganese needed for full growth. Furthermore, these requirements are dependent on the levels of all metals within the total metal pool. We were unable to demonstrate any growth limitation in the absence of added zinc in wildtype cells; however, in cells mutant in the zinc importer, encoded by znuC, zinc is limiting for growth. Development of this medium allows us to examine how cells adapt to trace metal availability. Under iron-limited conditions, the cell initiates an iron-sparing response. In the absence of the regulator of this response, fsrA, the cells require higher iron for growth. Not only does this media give us insight into the complex balance of intracellular metal pools, but it provides a tool for the analysis of metal limitation in Bacillus subtilis.
  • Item
    A study on the effectiveness of different RNAi expression systems in arresting Drosophila melanogaster embryos during early development
    Jin, Bozhou (2021-07)
    The technique to arrest Drosophila melanogaster embryos at a specific developmental stage is desirable to various applications that require a population with relatively uniform amount of DNA. One example is to measure the allelic frequencies using pooled sequencing (Wei et al. 2017). To achieve this, RNAi constructs activated by Gal4 proteins were used to knock down genes essential to D. melanogaster embryonic development. I tested the arresting efficiencies of six different RNAi constructs. Four of which had an arrest rate greater than 97.3% (trk-pNP, dl-pNP, dl-UASz, tor-UASz; the names are defined in Method section). I also found strong evidence indicating that the Gal4 gene locus was affecting the arrest rate. Several constructs also showed evidence that the age of the female expressing them could be an affecting factor. In spite of this, there was sometimes high variations between results from different replicas of the same RNAi constructs, which could be either due to random environmental factors or polymorphisms within the same fly lines. Further studies would therefore be needed to better address this internal variation, and to generalize the technique for D. melanogaster strains with different genetic backgrounds.
  • Item
    Identification of protein interaction partners of two-component system CvsSR in Pseudomonas syringae pathovar tomato DC3000.
    Pseudomonas syringae pathovar tomato (Pto) is a hemibiotrophic plant pathogen that proliferates aggressively in the tomato plant’s apoplast to cause disease. The Pto two-component system (TCS) CvsSR is essential for virulence in the apoplast, regulating numerous virulence genes. Its transmembrane histidine kinase CvsS senses environmental signals, and then activates its cognate cytoplasmic response regulator CvsR by phosphorylation. The activated CvsR subsequently acts as a transcription factor, affecting gene expression. In addition to the histidine kinase and response regulator interaction, some TCSs interact with other signaling systems, which increases the extent of their regulation. Because CvsSR affects the expression of genes belonging to regulatory pathways of other signaling systems, we hypothesized that it may be regulating these systems directly. To determine if CvsSR engages in regulatory interactions with other proteins, I performed a series of experiments to develop a functional oimmunoprecipitation protocol. First, I tested and confirmed the expression of plasmids transformed into Pto that contained the genes encoding CvsS or CvsR modified to include a targetable FLAG sequence. I then attempted various growth and immunoprecipitation conditions and identified the ones that produced protein interaction partners. The interaction partners of CvsS or CvsR were separated by SDS-PAGE, which revealed a single ~17 kDa band in both that was enriched for relative to the control. The protein band was identified by liquid chromatography coupled with dual mass spectrometry as 30S Ribosomal Subunit S5. The result suggests the discovery of a new type of interaction between a TCS and the ribosome.
  • Item
    Investigating the seasonal migration of Cobia (Rachycentron canadum) and the influence of temperature on movement ecology
    Gottesman, Hannah (2021-03)
    The pelagic Cobia (Rachycentron canadum) is the target of a popular recreational fishery from the Gulf of Mexico to the mid-Atlantic that shifts seasonally as these fish migrate along the east coast of the United States. Variation in migratory behaviors, when consistent through time, drives the formation of genetic substructure within a population. Movement ecology research works in combination with other stock delineation techniques, like genetic analyses, to indicate such population structure. Intrapopulation variability in spatio-temporal distributions has significant consequences for fishery encounter rates. Temperature is a proposed driver of this seasonal movement in Cobia. In this study, we used passive acoustic telemetry to investigate the migration of Atlantic Cobia. Our results corroborated the timing and spatial distribution of the described north-south Cobia spawning migration in which North Carolina waters serve as a migration corridor and Chesapeake Bay in Virginia is a major spawning site. We characterized seasonal differences in space use — longitudinal variation in path, with Cobia travelling nearshore in the spring and dispersing offshore in the fall — and other intrapopulation variation in migratory behavior (i.e., distinct subsets of Cobia overwintering offshore in North Carolina waters and spending the spawning period in marine habitat south of Chesapeake Bay) that will inform management of the fishery and future interpretation of genetic studies. Following our preliminary analysis, the influence of temperature (i.e., warm, thermally stable continental shelf habitat facilitating offshore overwintering in North Carolina) on the migration of this highly migratory species — and thus on a lucrative fishery — is better understood.
  • Item
    Investigations into the impact of and mechanisms behind age-associated impaired healing following peripheral nerve injury
    Miklavcic, William (2020-08)
    Peripheral nerve injuries (PNI) present a challenging and debilitating problem to both patients and the healthcare industry . Elderly patients in particular demonstrate a significantly reduced rate of recovery after PNI, prolonging the time they are in pain and immobile. Research into the mechanisms behind these age-associated healing impairments has the potential to unlock new ways to reverse this process and possibly accelerate the rate of recovery for all patients after PNI. Since macrophages and Schwann cells have been shown to be important in peripheral nerve repair, I sought to determine whether age had an effect on their recruitment to the site of a nerve injury. To do this, I first affirmed the impact that age has on both the rate of recovery and extent of full recovery after PNI through the use of hock angle analysis, peak tetanic force (PTF) measurements, and gastrocnemius (gastroc) muscle harvests. I then used novel nerve graft techniques to determine the impact the age of the nerve tissue has on macrophage and Schwann cell recruitment after PNI. While unable to detect age-related differences in rate of recovery after PNI, I found that recovery was similarly incomplete in both old and young animals. My new assay for quantifying macrophage and Schwann cell migration into the injured nerve proved a more convenient, cost-effective method that yielded results challenging previous conceptions by showing macrophage and Schwann cell recruitment was the same between young and old mice.
  • Item
    Exploring the role of differential gene expression in the age-associated impairment of peripheral nerve regeneration
    Sagar, Kareena (2020-06)
    The peripheral nervous system’s ability to regenerate after injury declines with age, but the reason for why this occurs is unknown. With the goal to understand the role of age-associated transcriptional changes in the impairment of peripheral nerve injury, I conducted a differential gene expression experiment using RNA sequencing and functional recovery experiments with gait analysis and peak tetanic force measurements. In young mice, genes involved in cell proliferation and neurogenesis were upregulated compared to old mice. In contrast, in aged mice I observed upregulation of genes encoding proteinases and pro-inflammatory cytokines. Following a peripheral nerve injury, young animals and old animals expressed a similar ability to activate regenerative transcriptional programs. Gait analyses and measurements of muscle strength showed no significant difference nor any delay in the ability of old animals to recover from peripheral nerve injury. In summary, this study identified several markers of inflammatory and immune system pathways and pathways involved in nerve regeneration that differ in their expression between young and old mice. Understanding the role of these pathways in nerve regeneration may provide therapeutic targets to enhance regeneration in aging individuals.
  • Item
    Genetic Basis of Rotenone-induced Parkinson’s Disease Model in Drosophila melanogaster
    Olarewaju, Iyaniwura (2020-06)
    Parkinson’s disease (PD) is a neurological disorder that exists in sporadic and familial forms and causes the death of dopamine-producing neurons in humans. Rotenone, a pesticide, can be used to induce a model of sporadic PD in Drosophila melanogaster. The genetic pathogenesis of PD is still being determined in both humans and D. melanogaster. Conducting a genome-wide association study on the genetic variation of D. melanogaster from the Drosophila Genetic Reference Panel (DGRP) with rotenone-induced PD uncovered a set of candidate genes that alter sensitivity to the pesticide. Many of these genes point to possibly important roles of natural variation in the Fibroblast Growth Factor (FGF) Pathway and microtubule synthesis. As microtubule is central to the transport of dopamine in D. melanogaster, these findings suggest a possible explanation of sporadic PD in humans based on genetic and environmental interactions.
  • Item
    Developing a Tool to Confirm the Successful Differentiation of Human Pluripotent Stem Cells into Cardiomyocytes
    Schuster, Calvin (2020-06)
    Heart disease has been the leading cause of death in the United States since 1921 (Greenlund et al., 2006). However, age-adjusted cardiovascular disease death rates have declined by 55% since 1950, a trend that is in part due to improvements in treatment (Greenlund et al., 2006). Researchers interested in developing effective heart disease treatments have begun using human myocardial cells derived from induced pluripotent stem cells (iPSCs) to build in vitro heart disease models, screen for new cardiovascular drugs or drug side effects, and study individualized cardiac therapy (Sinnecker et al., 2012). The future clinical use of iPSCs in cell therapy for cardiovascular disorders is also incredibly promising (Sinnecker et al., 2012). However, when differentiating iPSCs into cardiomyocytes, researchers currently have no tools available to confirm whether the differentiation was successful. The goal of this project was to create and test a tool that can confirm and quantify the successful differentiation of iPSCs into cardiomyocytes by coupling the GCaMP8 calcium indicator and the cardiomyocyte-specific promoter alpha myosin heavy chain (αMHC). A release of calcium ions triggers cardiomyocyte contraction (Marks, 2003). When calcium ions bind to GCaMP molecules a conformational change occurs that results in an increase in green fluorescence (Shui et al., 2014). Therefore, an αMHC-GCaMP8 cardiomyocyte cell line should produce green fluorescence during contraction. This project demonstrated the use of Lipofectamine 3000 to transfect human iPSCs with an αMHC-GCaMP8-iCAG insertion plasmid and the successful differentiation of transfected iPSCs into cardiomyocytes, and it suggests that differentiated cardiomyocytes fluoresce.
  • Item
    Parsing complex community interactions with regulators and non-governmental organizations in relation to local environmental management at Honeoye Lake, New York
    Yardley, Elizabeth (2019-05)
    This research sought to understand the complex interactions between governmental and non-governmental organizations engaged in assessing or managing the environmental issue of cyanobacterial blooms (commonly known as harmful algal blooms, or HABs) in Honeoye Lake, the second smallest Finger Lake in New York State. Honeoye Lake has a history of HABs that have been investigated for several years. However, while investigation of the ecological aspects of HABs has been ongoing, the intricate network of organizations that sometimes collaborate and sometimes compete to manage the lake was previously unstudied. Our research helps to clarify this complex network, which will prove important for future effective management. I found that a total of 24 stakeholder organizations interact in various ways, including financial, logistical, and managerial roles, with the majority of the interactions occurring at the state level. The New York State Department of Environmental Conservation interacts with the most stakeholder organizations involved with the HAB problem in Honeoye Lake. We did not find any significant correlation between: the number of interactions and hierarchical position; the number of interactions and physical distance; nor the physical distance and hierarchical distance between collaborating organizations.” However, this project unveiled a fascinating web of interactions between entities surrounding a complex environmental issue that was previously not well understood.
  • Item
    A comparison of ovarian morphology and reproductive and metabolic features between South Asian and White women with polycystic ovary syndrome (PCOS)
    Tam, Ashley (2019-05)
    Introduction: Polycystic ovary syndrome (PCOS) is a common endocrine condition, with known variability in the severity of its cardinal features and long-term health consequences across races and ethnicities. Diagnosis of PCOS involves the ultrasonographic identification of polycystic ovarian orphology (PCOM). However, current diagnostic thresholds for PCOM do not account for any impact of race or reflect the potential for race-specific differences in the presentation of PCOS. I aimed to evaluate differences in ovarian morphology between South Asian and White women with PCOS and assess relationships between reproductive / metabolic features and PCOM in both cohorts. Methods: White (n = 30) and South Asian (n = 31) women with PCOS underwent clinical evaluation, venipuncture, and transvaginal ultrasonography. Markers of PCOM (i.e., follicle number per ovary [FNPO] and ovarian volume [OV]) and reproductive / metabolic status were compared between groups. Results: South Asian women with PCOS had lower OV (9.0 vs. 12.5 mL, P 0.01) and slightly lower FNPO (31 vs. 44 follicles, P = 0.06) than White women with PCOS. South Asian women also had more metabolic disturbances than White women, as indicated by higher waist circumference, waist-to-hip ratio, and 2-hour glucose levels (All: P 0.05). Correlations between ovarian morphology and reproductive / metabolic features were variable across cohorts and challenging to interpret due to limited sample sizes. Conclusions: My findings support the need for race-specific diagnostic criteria for PCOM. Future studies would benefit from the inclusion of larger cohorts of South Asian and White women to clarify the importance of race in the manifestation and treatment of PCOS.