Chromosome segregation errors during cell divisions generate aneuploidies and micronuclei, which can undergo extensive chromosomal rearrangements such as chromothripsis1–5. Selective pressures then shape distinct aneuploidy and rearrangement patterns—for example, in cancer6,7—but it is unknown whether initial biases in segregation errors and micronucleation exist for particular chromosomes. Using single-cell DNA sequencing8 after an error-prone mitosis in untransformed, diploid cell lines and organoids, we show that chromosomes have different segregation error frequencies that result in non-random aneuploidy landscapes. Isolation and sequencing of single micronuclei from these cells showed that mis-segregating chromosomes frequently also preferentially become entrapped in micronuclei. A similar bias was found in naturally occurring micronuclei of two cancer cell lines. We find that segregation error frequencies of individual chromosomes correlate with their location in the interphase nucleus, and show that this is highest for peripheral chromosomes behind spindle poles. Randomization of chromosome positions, Cas9-mediated live tracking and forced repositioning of individual chromosomes showed that a greater distance from the nuclear centre directly increases the propensity to mis-segregate. Accordingly, chromothripsis in cancer genomes9 and aneuploidies in early development10 occur more frequently for larger chromosomes, which are preferentially located near the nuclear periphery. Our findings reveal a direct link between nuclear chromosome positions, segregation error frequencies and micronucleus content, with implications for our understanding of tumour genome evolution and the origins of specific aneuploidies during development.

New developments in the field of biomedicine can have extensive implications for society. To steer research efforts in a responsible direction, biomedical scientists should contribute to a forward-looking ethical, and societal evaluation of new developments. However, the question remains how to equip students sufficiently with the skills they need to contribute to this evaluation. In this paper, we examine how the four dimensions of Responsible Research and Innovation (anticipation, reflexivity, inclusivity, and responsiveness) inform the identification of learning goals and teaching approaches that contribute to developing these skills in biomedical scientists. We suggest that these educational approaches focus on the skills to anticipate intended and unintended outcomes, reflect on the epistemological and moral aspects of research practice, and be inclusive of the variety of voices in society. We argue that if these dimensions are properly integrated into biomedical curricula, they will help students develop the attitudinal aspects necessary for becoming responsive, and prepare them for implementing the dimensions of responsible research into their daily practice. This paper focuses specifically on skills biomedical scientists need for the responsible conduct of research. Therefore, our analysis results, at least in part, in domain-specific recommendations. We invite educators from other disciplines to do the same exercise, as we believe this could lead to tailored educational approaches by which students from various disciplinary backgrounds learn how they each have a role in contributing to socially robust and morally responsible research practice.

Moral sensitivity and moral reasoning are essential competencies biomedical researchers have to develop to make ethical decisions in their daily practices. Previous research has shown that these competencies can be developed through ethics education. However, it is unclear which underlying mechanisms best support the development of these competencies. In this article we argue that the development of moral sensitivity and moral reasoning can be fostered through teaching strategies that tap into students’ moral imagination. We describe how moral imagination can stimulate the development of these competencies through three different merits of moral imagination. Moral imagination can help students to 1) transfer and apply abstract moral concepts to concrete situations and contexts, 2) explore the perspective of others, 3) explore and foresee the moral consequences of different decisions and actions. We explain these three merits of moral imagination in the context of biomedical research and present a theoretical model for how these merits can be used to stimulate the development of moral sensitivity and moral reasoning. Furthermore, we describe multiple teaching strategies for biomedical curricula that tap into the three merits of moral imagination. These teaching strategies can inspire teachers to design ethics education that activates students’ moral imagination for the development of moral sensitivity and moral reasoning.