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Active learning can enhance student outcomes in STEM higher education, but its effectiveness varies with implementation. A key contributor to this variation is the pedagogical knowledge held by instructors. However, little is known about instructors’ pedagogical knowledge of how people learn, how these ideas develop over time, and how knowledge development influences active-learning implementation. This longitudinal qualitative study examined variation, development, and instructional implications of pedagogical knowledge among 11 early-career undergraduate life sciences instructors in the context of their active-learning instruction. We conducted semistructured interviews, including stimulated recall, capturing pedagogical knowledge used to plan, implement, and reflect on a lesson, repeating this process across multiple semesters. We used qualitative content analysis and an analytical framework to identify distinct pedagogical ideas about how people learn used by instructors and their alignment with passive, active, and generative cognitive engagement in the ICAP framework. Longitudinal comparisons revealed that participants did not consistently develop ideas aligned with generative cognitive engagement, indicating that teaching experience is necessary but insufficient to foster development of crucial pedagogical knowledge for effective active learning. Case studies illustrated how knowledge development can influence nuances of active-learning design and implementation. We discuss potential mechanisms of knowledge development and instructional implications. 

Effective teaching requires teachers to leverage their knowledge of how students think about and learn specific topics (i.e., pedagogical content knowledge). This longitudinal qualitative study of early-career biology instructors examines the development of this specialized teaching knowledge. 

Abstract Supergenes underlying complex trait polymorphisms ensure sets of coadapted alleles remain genetically linked. Despite their prevalence in nature, the mechanisms of supergene effects on genome regulation are poorly understood. In the fire ant Solenopsis invicta, a supergene containing over 500 individual genes influences trait variation in multiple castes to collectively underpin a colony level social polymorphism. Here, we present results of an integrative investigation of supergene effects on gene regulation. We present analyses of ATAC-seq data to investigate variation in chromatin accessibility by supergene genotype and STARR-seq data to characterize enhancer activity by supergene haplotype. Integration with gene co-expression analyses, newly mapped intact transposable elements (TEs), and previously identified copy number variants (CNVs), collectively reveal widespread effects of the supergene on chromatin structure, gene transcription, and regulatory element activity, with a genome-wide bias for open chromatin and increased expression in the presence of the derived supergene haplotype, particularly in regions that harbor intact TEs. Integrated consideration of CNVs and regulatory element divergence suggests each evolved in concert to shape the expression of supergene encoded factors, including several transcription factors that may directly contribute to the trans-regulatory footprint of a heteromorphic social chromosome. Overall, we show how genome structure in the form of a supergene has wide-reaching effects on gene regulation and gene expression. 

Characterizing molecular underpinnings of plastic traits and balanced polymorphisms represent two important goals of evolutionary biology. Fire ant gynes (pre-reproductive queens) provide an ideal system to study potential links between these phenomena because they exhibit both supergene-mediated polymorphism and nutritional plasticity in weight and colony-founding behavior. Gynes with the inversion supergene haplotype are lightweight and depend on existing workers to initiate reproduction. Gynes with only the ancestral, non-inverted gene arrangement accumulate more nutrient reserves as adults and, in a distinct colony-founding behavior, initiate reproduction without help from workers. However, when such gynes overwinter in the natal nest they develop an environmentally induced lightweight phenotype and colony-founding behavior, similar to gynes with the inversion haplotype that have not overwintered. To evaluate the extent of shared mechanisms between plasticity and balanced polymorphism in fire ant gyne traits, we assessed whether genes with expression variation linked to overwintering plasticity may be affected by evolutionary divergence between supergene haplotypes. To do so, we first compared transcriptional profiles of brains and ovaries from overwintered and non-overwintered gynes to identify plasticity-associated genes. These genes were enriched for metabolic and behavioral functions. Next, we compared plasticity-associated genes to those differentially expressed by supergene genotype, revealing a significant overlap of the two sets in ovarian tissues. We also identified sequence substitutions between supergene variants of multiple plasticity-associated genes, consistent with a scenario in which an ancestrally plastic phenotype responsive to an environmental condition became increasingly genetically regulated.