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Postdoc Spotlight

Thursday, April 29th at 12pm EDT/18:00 CEST

Join us for a special Club EvMed where we’ll be highlighting some of the exciting work done by postdoctoral researchers in the field of evolutionary medicine. We will hear 12-minute research talks from Kyle CardLiz Lange, and Federica Pierini (see abstracts below). There will be a brief Q&A period at the end of each talk, plus breakout rooms after all 3 talks to allow for more in depth conversations with the speakers. Sign up here for the meeting link.

“The effect of population size, mutation rate, and genetic background on the evolution of antibiotic resistance” by Kyle Card, Cleveland Clinic
The evolution of antibiotic resistance is a serious and growing problem. The ability to predict a pathogen’s capacity to evolve resistance is therefore a critical public-health goal. In previous work, we found that differences between genetic backgrounds can sometimes lead to unpredictable responses in phenotypic resistance and influence its genetic basis by channeling evolution down particular mutational paths. However, it is still not clear how background interacts with other factors, including population size and mutation rate to influence resistance evolution. To address this issue, we are combining theory with an experimental examination of a time-series of E. coli strains isolated from a population that evolved increases in both population size and mutation rate during a long-term evolution experiment (LTEE).

“Female-female social bonds mediate the relationship between early life adversity and lifespan in wild baboons, but female-male social bonds do not” by Liz Lange, Duke University
Adversities experienced during early life and adult social environments can have profound effects on human health and survival. However, it is unclear if experiences during early life and adulthood exhibit independent effects on survival, or instead if these processes are linked such that adverse early experiences are strongly coupled with dysfunction in adult social relationships, which in turn are strongly coupled with decreased lifespan. In this study we used longitudinal data on 199 wild adult female baboons from the Amboseli ecosystem in Kenya to determine the links between early life adversity, adult social bonds, and adult survival outcomes. We find that early adversity and social isolation from both males and females reduce survival, but only female-female social bonds link early life adversity to reduced survival. Our results suggest that the timing of effects (e.g., the effect of early adversity on social bonds and social bonds on survival) are crucial to determining the links between these processes and should be considered in human studies of adverse childhood experiences.

“Exploring immunogenetic diversity in historical human populations” by Federica Pierini, Max Planck Institute for the Science of Human History
The highly polymorphic genes of the human leukocyte antigen (HLA) system play a key role in adaptive immunity. Pathogen-mediated selection is proposed to be one of the major factors affecting the genetic variability at those genes, but our knowledge is so far based on information acquired from the study of present-day human populations. The investigation of ancient HLA genes in historical populations could shed further light on mechanisms of pathogen-mediated selection in humans. I will first show our novel aDNA-optimized pipeline for low-coverage and low-quality shotgun sequence data and follow with two examples of its applicability. The approach has been successfully applied to a dataset of Late Neolithic samples from a collective burial in Niedertiefenbach (Germany), revealing a distinct and characteristic HLA gene pool compared to modern day German individuals, and to a dataset of medieval European samples, associating HLA variability with susceptibility to leprosy.

The COVID-19 Pandemic and Human Nature: An Interdisciplinary Conversation

Monday, May 10th at 12pm EDT

This Club EvMed will feature a dynamic roundtable conversation with several authors of the recently published PNAS paper, “The pandemic exposes human nature: 10 evolutionary insights.” Moderated by Dan Blumstein (Professor of Ecology and Evolutionary Biology at UCLA), the panel’s discussants will include Athena Aktipis (Assistant Professor of Psychology at Arizona State University), Martie Haselton (Professor of Psychology at UCLA), and Joe Alcock (Professor of Emergency Medicine at the University of New Mexico). They will provide a range of evolutionary insights and hypotheses related to the impact of COVID-19 on human health and social systems. Sign up here for the meeting link.

Divergent evolutionary roots for posttraumatic stress disorder symptoms

Monday, May 17th at 12pm EDT

Join us for a conversation with Sarah Mathew, Associate Professor in the School of Human Evolution and Social Change at Arizona State University, and Matthew Zefferman, Assistant Professor in the Department of Defense Analysis at the Naval Postgraduate School. Military personnel in industrialized societies often develop Post-traumatic Stress Disorder (PTSD) during combat. It is unclear whether combat-related PTSD is a universal evolutionary response to danger, or a culture-specific syndrome of industrialized societies. We interviewed 218 Turkana pastoralist warriors in Kenya, who engage in lethal cattle raids, about their combat experiences and PTSD symptoms. Compared to American combat veterans, Turkana suffer PTSD symptoms at high rates, but have lower prevalence of depression-like PTSD symptoms. Symptoms that facilitate responding to danger were better predicted by combat exposure, whereas depressive symptoms were better predicted by exposure to combat-related moral violations. The findings suggest that some PTSD symptoms stem from a universal response to danger, while depressive PTSD symptoms may be caused by culturally-specific moral norm violations.

Attendees are encouraged to read Zefferman and Mathew 2021, “Combat stress in a small-scale society suggests divergent evolutionary roots for posttraumatic stress disorder symptoms” and Zefferman and Mathew 2020, “An evolutionary theory of moral injury with insight from Turkana warriors.” Sign up here for the meeting link.