Stigma Mutation: Tracking Lineage, Variation and Strength in Emerging COVID-19 Stigma

In this article, I propose a novel theoretical framework for conceptualizing pandemic stigma using the metaphor of ‘mutation’. This metaphor highlights that stigma is not a static or fixed state but is enacted through processes of continuity and change. The following three orienting concepts are identified: (a) lineage (i.e. origin narratives and initial manifestations are created in relation to existing stigmas, stereotypes, and outgroups), (b) variation (i.e. stigma changes over time in response to new content and contexts), and (c) strength (i.e. stigma can be amplified or weakened through counter- or de-stigmatizing forces). I go on to use this metaphor to offer an analysis of the emergence of COVID-19 stigma. The lineage of COVID-19 stigma includes a long history of contagious disease, resonant with fears of contamination and death. Origin narratives have stigmatized Asian/Chinese groups as virus carriers, leading to socio-political manifestations of discrimination. Newer ‘risky’ groups have emerged in relation to old age, race and ethnicity, poverty, and weight, whose designation as ‘vulnerable’ simultaneously identifies them as victims in need of protection but also as a risk to the social body. Counter-stigmatizing trends are also visible. Public disclosure of having COVID-19 by high-status individuals such as the actor Tom Hanks has, in some instances, converted ‘testing positive’ into shared rather than shamed behaviour in the West. As discourses concerning risk, controllability, and blame unfold, so COVID-19 stigma will further mutate. In conclusion, the metaphor of mutation, and its three concepts of lineage, variation, and strength, offers a vocabulary through which to articulate emergent and ongoing stigma processes. Furthermore, the concept of stigma mutation identifies a clear role for social scientists and public health in terms of process engagement; to disrupt stigma, remaking it in less deadly forms or even to prevent its emergence altogether.

How the footprint of history shapes the evolution of digital organisms

Gould’s thought experiment of “replaying life’s tape” provides a conceptual framework for experiments that quantify the contributions of adaptation, chance, and history to evolutionary outcomes. For example, we can empirically measure how varying the depth of history in one environment influences subsequent evolution in a new environment. Can this “footprint of history”—the genomic legacy of prior adaptation—grow too deep to overcome? Can it constrain adaptation, even with intense selection in the new environment? We investigated these questions using digital organisms. Specifically, we evolved ten populations from one ancestor under identical conditions. We then replayed evolution from three time points in each population’s history (corresponding to shallow, intermediate, and deep history) in two new environments (one similar and one dissimilar to the prior environment). We measured the contributions of adaptation, chance, and history to the among-lineage variation in fitness and genome length in both new environments. In both environments, variation in genome length depended largely on history and chance, not adaptation, indicating weak selection. By contrast, adaptation, chance, and history all contributed to variation in fitness. Crucially, whether the depth of history affected adaptation depended on the environment. When the ancestral and new environments overlapped, history was as important as adaptation to the fitness achieved in the new environment for the populations with the deepest history. However, when the ancestral and novel environments favored different traits, adaptation overwhelmed even deep history. This experimental design for assessing the influence of the depth of history is promising for both biological and digital systems.

Variation in self-compatibility among genotypes and across ontogeny in a self-fertilizing vertebrate

Mixed mating strategies offer the benefits of both self-fertilizing one’s own eggs (selfing) and outcrossing, while limiting the costs of both methods. The economics of mixed mating is further determined by individual self-compatibility. In gynodioecious (hermaphrodites, females) and androdioecious (hermaphrodites, males) species, the level of self-compatibility of the hermaphrodites also acts as a selection pressure on the fitness of the other sex. Mangrove rivulus fish populations are comprised of selfing hermaphrodites and males that result from hermaphrodites changing sex. Although hermaphrodites overwhelmingly reproduce through internal selfing, they occasionally oviposit unfertilized eggs. Males can externally fertilize these eggs. Here, we reveal that fecundity and self-compatibility varies within individuals across ontogeny until about 365 days post hatch, and among individuals derived from lineages that vary in their propensity to change sex. Hermaphrodites from high sex changing lineages were significantly less fecund and self-compatible than hermaphrodites from low sex changing lineages. These differences in self-compatibility and fecundity have the potential to drive evolutionary changes on mating strategy and the fitness of males in populations of the mangrove rivulus. This study also illustrates the importance of including lineage variation when estimating the costs and benefits of mixed mating strategies.

The role of behavioural flexibility in primate diversification

Understanding impacts on species diversification is fundamental to our understanding of the evolutionary processes underlying biodiversity. The ‘behavioural drive hypothesis’ posits that behavioural innovation, coupled with the social transmission of innovative behaviours, can increase rates of evolution and diversification, as novel behaviours expose individuals to new selection regimes. We test this hypothesis within the primates, a taxonomic group with considerable among-lineage variation in both species diversity and behavioural flexibility. We employ a time cut-off in our phylogeny to help account for biases associated with recent taxonomic reclassifications and compare three alternative measures of diversification rate that consider different phylogenetic depths. We find that the presence of behavioural innovation and social learning are positively correlated with diversification rates among primate genera, but not at shallower taxonomic depths. Given that we find stronger associations when examining older as opposed to newer diversification events even after controlling for potential sampling biases, we suggest that extinction resistance may be an important mechanism linking behavioural flexibility and diversification in primates. If true, our findings offer support for an expanded view of the behavioural drive hypothesis, and key predictions of this hypothesis can be tested as primates are forced to respond to ongoing environmental change.

Variation in male reproductive system characters in Corydoradinae (Loricarioidei: Callichthyidae) reflects the occurrence of different lineages in this subfamily

ABSTRACT Callichthyidae comprises a well-corroborated monophyletic group divided into two subfamilies: Corydoradinae and Callichthyinae. A recent proposal, based on molecular data, suggests that Corydoradinae is composed by nine monophyletic lineages, possibly genera. The species pertaining to those lineages have extensive modification in the size of genome, including diploid, tetraploid and octoploid species. Considering the occurrence of these monophyletic lineages and that the variations in DNA content may imply in significant alterations on the structure of spermatozoa, this study analyzed the morphology of the male reproductive system and the morphometry of the head of the spermatozoa of representatives of the nine lineages of Corydoradinae, seeking for particular characteristics of each lineage. Morphological data revealed a high intra-lineage variation, larger than that observed among species of different lineages. In contrast, morphometric data obtained for eight out of the nine lineages, revealed large congruency with the hypothesis that Corydoradinae is composed by different lineages. These results demonstrate that there is a correlation among variations in DNA content and the size of the spermatozoon head, thus providing additional subsides for the definition of the Corydoradinae lineages.