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Biology subjects

Tucker-Kellogg, G.

Publications and source records attributed to Tucker-Kellogg, G..

2 recordsLinked to original sources

Developing critical thinking in STEM education through inquiry-based writing in the laboratory classroom

Laboratory pedagogy is moving away from step-by-step instructions and toward inquiry-based learning (IBL), but only now developing methods for integrating inquiry-based writing (IBW) practices into the laboratory course. Based on an earlier proposal (Science 332:919 (2011)), we designed and implemented an IBW sequence in a university bioinformatics course.\n\nWe automatically generated unique, double-blinded, biologically plausible DNA sequences for each student. After guided instruction, students investigated sequences independently and responded through IBW writing assignments. IBW assignments were structured as condensed versions of a scientific research paper, and because the sequences were double blinded, they were also assessed as authentic science and evaluated on clarity and persuasiveness.\n\nWe piloted the approach in a seven-day workshop (35 students) at Perdana University Graduate School of Medicine in Kuala Lumpur. We observed dramatically improved student engagement and indirect evidence of improved learning outcomes over a similar workshop without IBW. Based on student feedback, initial discomfort with the writing component abated in favor of an overall positive response and increasing comfort with the high demands of student writing. Similarly encouraging results were found in a semester length undergraduate module at the National University of Singapore (155 students).

scientific communication and education

H3K27me3-rich genomic regions can function as silencers to repress gene expression via chromatin interactions

Gene repression and silencers are poorly understood. We reasoned that H3K27me3-rich regions (MRRs) of the genome defined from clusters of H3K27me3 peaks may be used to identify silencers that can regulate gene expression via proximity or looping. MRRs were associated with chromatin interactions and interact preferentially with each other. MRR component removal at interaction anchors by CRISPR led to upregulation of interacting target genes, altered H3K27me3 and H3K27ac levels at interacting regions, and altered chromatin interactions. Chromatin interactions did not change at regions with high H3K27me3, but regions with low H3K27me3 and high H3K27ac levels showed changes in chromatin interactions. The MRR knockout cells also showed changes in phenotype associated with cell identity, and altered xenograft tumor growth. MRR-associated genes and long-range chromatin interactions were susceptible to H3K27me3 depletion. Our results characterized H3K27me3-rich regions and their mechanisms of functioning via looping.

genomics