Improving Academic Performance and Retention of First-Year Biology Students through a Scalable Peer Mentorship Program.

We examine the impact of Biology Mentoring and Engagement (BIOME) near-peer mentorship on 437 first-year undergraduate students over three cohort years. The BIOME course consists of ten, 50-minute meetings where groups of six first-year mentees meet with an upper-division student mentor to discuss topics including metacognition, growth mindset, and effective study strategies. We employed a mixed-methods approach to evaluate the impact of BIOME on mentee academic outcomes. Initial ethnographic analysis revealed that BIOME influenced student study methods, approaches to academic challenges, and use of campus learning communities. We then constructed a novel, program-specific instrument to measure the implementation of these habits, a construct we named "academic habit complexity." Regression analysis supported the hypothesis that enrollment in BIOME leads to students using more diverse approaches than their peers. Enrollment in BIOME, and the associated development of academic habit complexity, is related to higher course grades in General Chemistry, a biology major prerequisite. Finally, students participating in BIOME demonstrated improved short-term student retention as measured by increased enrollment in the subsequent prerequisite General Chemistry course. These results suggest that course-based near-peer mentorship may be an effective and scalable approach that can promote student academic success.

Improving Academic Performance, Belonging, and Retention through Increasing Structure of an Introductory Biology Course.

Integration of active-learning approaches into increased-structure postsecondary classrooms significantly improves student academic outcomes. We describe here two parallel sections of Introductory Biology that shared learning objectives and content but varied in course structure. The large-enrollment traditional course consisted of four 50-minute lectures coupled with minimal active-learning techniques, while an increased-structure intervention course integrated multiple active-learning approaches, had limited enrollment, and comprised three 50-minute lectures combined with a fourth peer-led team-learning discussion section. Additionally, the intervention course employed weekly review quizzes and multiple in-class formative assessments. The academic impact of these two course formats was evaluated by use of common exam questions, final grade, and student retention. We showed that academic achievement and retention of participants enrolled in the intervention course was significantly improved when compared with the traditional section. Further, we explored whether promoting in-class student-student/student-instructor interactions and peer-led discussion sections fostered a greater sense of belonging. At the end of the course, participants in the intervention course reported greater perceptions of classroom belonging. Therefore, this study begins to characterize the importance of combining pedagogical methods that promote both academic success and belonging to effectively improve retention in science, technology, engineering, and mathematics majors.

Discontinuities in Rap1 activity determine epithelial cell morphology within the developing wing of Drosophila.

Mechanisms that govern cell-fate specification within developing epithelia have been intensely investigated, with many of the critical intercellular signaling pathways identified, and well characterized. Much less is known, however, about downstream events that drive the morphological differentiation of these cells, once their fate has been determined. In the Drosophila wing-blade epithelium, two cell types predominate: vein and intervein. After cell proliferation is complete and adhesive cell-cell contacts have been refined, the vast majority of intervein cells adopt a hexagonal morphology. Within vein territories, however, cell-shape refinement results in trapezoids. Signaling events that differentiate between vein and intervein cell fates are well understood, but the genetic pathways underlying vein/intervein cyto-architectural differences remain largely undescribed. We show here that the Rap1 GTPase plays a critical role in determining cell-type-specific morphologies within the developing wing epithelium. Rap1, together with its effector Canoe, promotes symmetric distribution of the adhesion molecule DE-cadherin about the apicolateral circumference of epithelial cells. We provide evidence that in presumptive vein tissue Rap1/Canoe activity is down-regulated, resulting in adhesive asymmetries and non-hexagonal cell morphologies. In particular Canoe levels are reduced in vein cells as they morphologically differentiate. We also demonstrate that over-expression of Rap1 disrupts vein formation both in the developing epithelium and the adult wing blade. Therefore, vein/intervein morphological differences result, at least in part, from the patterned regulation of Rap1 activity.

Rap1 maintains adhesion between cells to affect Egfr signaling and planar cell polarity in Drosophila.

The small GTPase Rap1 affects cell adhesion and cell motility in numerous developmental contexts. Loss of Rap1 in the Drosophila wing epithelium disrupts adherens junction localization, causing mutant cells to disperse, and dramatically alters epithelial cell shape. While the adhesive consequences of Rap1 inactivation have been well described in this system, the effects on cell signaling, cell fate specification, and tissue differentiation are not known. Here we demonstrate that Egfr-dependent cell types are lost from Rap1 mutant tissue as an indirect consequence of DE-cadherin mislocalization. Cells lacking Rap1 in the developing wing and eye are capable of responding to an Egfr signal, indicating that Rap1 is not required for Egfr/Ras/MAPK signal transduction. Instead, Rap1 regulates adhesive contacts necessary for maintenance of Egfr signaling between cells, and differentiation of wing veins and photoreceptors. Rap1 is also necessary for planar cell polarity in these tissues. Wing hair alignment and ommatidial rotation, functional readouts of planar cell polarity in the wing and eye respectively, are both affected in Rap1 mutant tissue. Finally, we show that Rap1 acts through the effector Canoe to regulate these developmental processes.