Philosophy of Science 

The Scope and Limits of Reasoning Practices in Behavioral Genetics  

My dissertation examines the scope and limits of reasoning practices in behavioral genetic research by building on existing scholarship in philosophy of science and bioethics that analyzes aspects of human behavioral genetics. I am guided by a central observation: although philosophers of science have explored the epistemic practices related to the use of model organism in scientific research, especially in genetics and medicine, and have engaged critically with inferential maneuvers present in human behavioral genetic research, philosophical interest in these two domains has yet to overlap. There is little (if any) attention paid to how behavioral genetic researchers experimentally investigate the complex relationships between behavioral variation and genetic variation in fruit flies, mustard plants, and zebrafish. My philosophical investigation of this intersection will proceed by examining previously unexplored or underdeveloped conceptual issues arising from behavioral genetics studies in human, non-human, and non-human model organisms. Rather than focusing on the “nature versus nurture” debate, I will analyze what can be known through different kinds of investigations in the field of behavioral genetics, from the observational to the experimental.  

Idealization, De-Idealization, And Mechanistic Modeling

The practice of de-idealization has not received sufficient attention in domains of modeling where idealization has not been well studied, such as mechanistic models in biology. We lack an adequate understanding of how mechanistic models can be idealized and therefore are handicapped in evaluating how they might be de-idealized. This paper attempts to fill that gap. I juxtapose considerations of idealization in mechanistic models with the analysis of de-idealization as recomposing, reformulating, and situating in Knuuttila & Morgan (2019) to explore how de-idealization might be conceptualized in mechanistic models. To illustrate the value of this combination, I use a familiar case study: the Hodgkin-Huxley model of nerve transmission.


Creative Role of Stress In Evolution and Development

“Stress” is a metaphor used across diverse sciences, from psychology and cell biology to material science. “stress” can have discipline specific meanings, but its function can also vary widely even just within biology. the usage of stress varies so widely because stress can be seen as both explanans and explanandum within scientific research. Recently Dietmar Kultz has attempted to solve the muddle of stress by defining biological stress solely in terms of the laws of physics in his paper Defining Biological Stress and Stress Responses Based on Principles of Physics. Kultz argues that biological stress can be understood through the application of Hookes law which defines stress in terms of how much the physical structure of an object changes when a force is applied to a material. Given that stress is used as both explanans and explanandum, attempts made by those who want to reduce biological stress to physical stress may not serve all the investigative and explanatory purposes biologists want from the term Thus, I explore how the term stress is used by biologists in a specific context:  investigating the impact of temperature on canalization (i.e., the channeling of developmental pathways to generate stable outcomes despite varying conditions). In doing so I recognize that biologists interested in canalization are working with a different concept of stress than the physical reductionists are. I am not ignoring this difference, but instead, am interested in investigating why the physical-reductionist view of stress might not fit the investigative purposes of the biologists focused on canalization. 


CRISPR, Gatekeeping, and Genetic Determinism: Foregrounding Disabled and Marginalized Voices in Gene Editing Policies

Preliminary policy recommendations regarding the ethical use of CRISPR for human germline editing do not sufficiently consider the concerns of marginalized groups. Lauren's research project "CRISPR, Gatekeeping, and Genetic Determinism: Foregrounding Disabled and Marginalized Voices in Gene Editing Policies" draws on interdisciplinary sources from biology, philosophy, and disability studies to create new recommendations for using CRISPR in human reproduction that account for disabled and marginalized communities who will be disproportionately affected. These policy recommendations will address two areas of concern within the CRISPR technology literature: (1) problematic reliance on deterministic reasoning in genetics; and, (2) subtle gatekeeping ensured by current policy through “morbidity” stipulations.  

Future Systems of Xenotransplantation: Melding Historical and Bioethical Methodology 

The future of xenotransplantation is promising. However, the scientific process behind xenotransplantation, shown through the methodology of history and bioethics, involves stakeholders beyond the laboratory. We present three short vignettes, the history of a 20 th -century pioneer in solid organ transplantation, the xenoheart received by David Bennett, and a global system of illegal organ procurement, to highlight the complexity of biomedical practice. Current solid organ transplantation systems are seemingly unsustainable and ineffective to satisfy a growing global demand for organs. Despite the shortcomings of current systems, we argue that the discourse surrounding xenotransplantation science is insufficient to construct a long-lasting and equitable replacement for solid organ transplantation. Xenotransplantation is more than a surgical technique, an interdisciplinary health concern, or a biomedical technology—it is deeply dependent on a series of cultural, historical, and social factors. Incorporating a greater variety of perspectives and disciplines into ongoing discussions of xenotransplantation science, while potentially frustrating in the short term, will act to maximize its potential as a paradigm-shifting science.

Lab Experience: Arabidopsis & Drosophila 

Participation of the PIRL9 Gene in Arabidopsis Root Development

Root formation is a complex developmental process that involves cell elongation, differentiation, lateral root initiation, and responses to environmental factors - all processes dependent on gene products and the proper timing and location of their expression. Previous studies suggest the Arabidopsis thaliana PIRL9 gene could be involved in root development. If PIRL9 is involved in root development, PIRL9 should be expressed in root tissue, and pirl9 mutants should display abnormal phenotypes. To explore PIRL9 gene expression in primary and lateral roots, a reporter gene construct was made by attaching DNA encoding the GUS enzyme to the pirl9 promoter and inserted this construct into the A. thaliana genome.  A. thaliana lines containing this construct were used to examine PIRL9 gene expression in various tissues. In addition, PIRL9 expression was examined along the primary and lateral roots at different developmental stages. In order to elucidate PIRL9 function, primary root length and lateral root number and frequency in pirl9 knockout mutant plants were compared to wild-type controls, as well as in plants defective in a closely related gene, PIRL3. Findings confirm that PIRL9 is expressed in a variety of different developmental contexts, including early embryos at the start of primary root formation, and primary and lateral root tissue. PIRL9 was especially present in primary roots near the formation of lateral roots and lateral root buds. Pirl9 knockout studies revealed the diversity of morphology that A. thaliana primary and lateral roots exhibit under a variety of different environmental conditions.    

Melanic Pigmentation And Light Preference Within and Between Two Drosophila Species

Environmental adaptation and species divergence often involve suites of co-evolving traits. Pigmentation in insects presents a variable, adaptive, and well-characterized class of phenotypes for which correlations with multiple other traits have been demonstrated. In Drosophila, the pigmentation genes ebony and tan have pleiotropic effects on flies' response to light, creating the potential for correlated evolution of pigmentation and vision. Here, we investigate differences in light preference within and between two sister species, Drosophila americana and D. novamexicana, which differ in pigmentation in part because of evolution at ebony and tan and occupy environments that differ in many variables including solar radiation. We hypothesized that lighter pigmentation would be correlated with a greater preference for environmental light and tested this hypothesis using a habitat choice experiment. In a first set of experiments, using males of D. novamexicana line N14 and D. americana line A00, the light-bodied D. novamexicana was found slightly but significantly more often than D. americana in the light habitat. A second experiment, which included additional lines and females as well as males, failed to find any significant difference between D. novamexicana-N14 and D. americana-A00. Additionally, the other dark line of D. americana (A04) was found in the light habitat more often than the light-bodied D. novamexicana-N14, in contrast to our predictions. However, the lightest line of D. americana, A01, was found substantially and significantly more often in the light habitat than the two darker lines of D. americana, thus providing partial support for our hypothesis. Finally, across all four lines, females were found more often in the light habitat than their more darkly pigmented male counterparts. Additional replication is needed to corroborate these findings and evaluate conflicting results, with the consistent effect of sex within and between species providing an especially intriguing avenue for further research. 

Cooley, A.M., S. Schmitz, *E. J. Cabrera, *M. Cutter, *M. Sheffield, *I. Gingerich, *G. Thomas, *C. N. M. Lincoln , *V. H. Moore, *A. E. Moore, *S. A. Davidson , *N. Lonberg, *E. B. Fournier, *S. Love, *G. Posch, *M. B. Bihrle, *S. D. Mayer, *K. Om, *L. Wilson, *C. Q. Doe, *C. E. Vincent , *E. R. T. Wong, *I. Wall, *J. Wicks, *S. Roberts (2021). Melanic pigmentation and light preference within and between two Drosophila species. Ecology & Evolution 12 August 2021.