Visual Literacy of Molecular Biology Revealed through a Card-Sorting Task

Visual literacy, which is the ability to effectively identify, interpret, evaluate, use, and create images and visual media, is an important aspect of science literacy. As molecular processes are not directly observable, researchers and educators rely on visual representations (e.g., drawings) to communicate ideas in biology. How learners interpret and organize those numerous diagrams is related to their underlying knowledge about biology and their skills in visual literacy. Furthermore, it is not always obvious how and why learners interpret diagrams in the way they do (especially if their interpretations are unexpected), as it is not possible to “see” inside the minds of learners and directly observe the inner workings of their brains. Hence, tools that allow for the investigation of visual literacy are needed. Here, we present a novel card-sorting task based on visual literacy skills to investigate how learners interpret and think about DNA-based concepts. We quantified differences in performance between groups of varying expertise and in pre- and postcourse settings using percentages of expected card pairings and edit distance to a perfect sort. Overall, we found that biology experts organized the visual representations based on deep conceptual features, while biology learners (novices) more often organized based on surface features, such as color and style. We also found that students performed better on the task after a course in which molecular biology concepts were taught, suggesting the activity is a useful and valid tool for measuring knowledge. We have provided the cards to the community for use as a classroom activity, as an assessment instrument, and/or as a useful research tool to probe student ideas about molecular biology

Evolutionary paths to macrolide resistance in a Neisseria commensal converge on ribosomal genes through short sequence duplications

Neisseria commensals are an indisputable source of resistance for their pathogenic relatives. However, the evolutionary paths commensal species take to reduced susceptibility in this genus have been relatively underexplored. Here, we leverage in vitro selection as a powerful screen to identify the genetic adaptations that produce azithromycin resistance (� 2 μg/mL) in the Neisseria commensal, N. elongata. Across multiple lineages (n = 7/16), we find mutations that reduce susceptibility to azithromycin converge on the locus encoding the 50S ribosomal L34 protein (rpmH) and the intergenic region proximal to the 30S ribosomal S3 protein (rpsC) through short tandem duplication events. Interestingly, one of the laboratory evolved mutations in rpmH is identical (7LKRTYQ12), and two nearly identical, to those recently reported to contribute to high-level azithromycin resistance in N. gonorrhoeae. Transformations into the ancestral N. elongata lineage confirmed the causality of both rpmH and rpsC mutations. Though most lineages inheriting duplications suffered in vitro fitness costs, one variant showed no growth defect, suggesting the possibility that it may be sustained in natural populations. Ultimately, studies like this will be critical for predicting commensal alleles that could rapidly disseminate into pathogen populations via allelic exchange across recombinogenic microbial genera