A Conversation between Hungry Giraffes, Cultivated Daphnia and Heated Worms
Hungry giraffes rely on their long necks to reach the top of trees where yummy leaves are to be eaten. Do giraffes have long necks because they pull themselves towards elevated food? Or, do they have long necks because the ones who do not, well… they die of hunger and do not reproduce? This is how a sociocultural anthropologist remembers her biology teacher introducing Lamarckian versus Darwinian theories of evolution, with the latter winning over the former. I wonder which question can be asked about giraffes today, in light of the fascinating talks given during the themed session: “Inclusive Inheritance” at the Evolution Evolving conference.
This international gathering over the first four days of April 2019 happened at Churchill College in Cambridge (UK). One could read in the Conference Welcome text that “the title of this meeting endeavours to highlight both that the evolutionary process itself evolves over time and that evolutionary biology is a vibrant field of enquiry with a theoretical framework that also evolves.” The organizers also highlighted the “contributions to the history and philosophy of evolutionary biology”, promoting interdisciplinary discussions beyond the classical divide of natural / human & social sciences. This active intervention of breaking down disciplinary frontiers by putting academics of diverse backgrounds in same rooms is a powerful sociological intervention through administrative will. But, having researchers from different disciplinary backgrounds, and working on similar topics, talk to one another is not the only interdisciplinary expression I could enjoy.
Some social scientists are particularly excited by the emergence of “epigenetics” and its connections to socio-cultural-historical environments. I am one of them. The reason for my interest in epigenetics and inheritance is that biologists explicitly break down disciplinary boundaries through their experiments and the narrations of them. Listening to the four papers presented at the “Inclusive Inheritance” themed session, I learned a lot about the questions that life scientists are currently asking to investigate extra-genetic inheritance. I was amazed by how the “environment” was deeply rooted in concerns about “climate change” and “anthropogenic stressors”.
The transmission of acquired traits is a major topic of Lamarckian theory of evolution, though current debates wonder if epigenetics inheritance is intergenerational (over a few generations) or transgenerational (over many generations), which would make a difference in terms of evolution significance. Over the course of that afternoon, the audience could hear how biological research interrogates links between inheritance of acquired traits and human-induced stressful environments.
At the University of Liverpool and the institute of integrative biology, cultivated Daphnia, Dr Stewart Plaistow and Marco Marcello (who analyses data) may have some answers. Daphnia are small aquatic crustacean sometimes called “water fleas” because of how they move.
Dr Plaistow, thinks that Daphnia “is a very cool system”: These crustaceans are clonal, making it easy to see differences of phenotypes. Furthermore, it is easy to repeat experiments because they have short generation time. The talk invited the public to think about maternal states, about how maternal environments can influence egg composition and subsequently offspring life histories. One slide caught my attention as it summarized why “egg phenotypes are critical”.
I shared this image to two colleagues who asked me why I was so interested by this talk. Being in the room, I contextualized this image through what preceded it and what followed it. Daphnia were in the image without being in it. Of course, one of my colleagues, who is pregnant, reacted quite differently and said: “Is it me who is a bit susceptible lately, or this slide, that was written with the best and purest intention, can be read as blaming pregnant people a little? For the phenotypical outcome.” I suddenly saw the slide differently, out of context, and, indeed, saw a story of human heterosexual reproduction that could be focusing on individual responsibilities (blue “dad” and pink “mom” fighting over DNA appropriation). I commented back: “Translated in another context, it might be read like that…tricky…Janelle Lamoreaux has written on that.”
Janelle Lamoreaux is a sociocultural anthropologist who is researching endocrine disruptors’ science in China. She has published a fascinating article entitled “What if the Environment is a Person? Lineages of Epigenetic Science in a Toxic China”, where she invites to reflect on scales of analysis. Indeed, interpretative conclusions are not the same if the focus is on individuals as environments or on environments shaping individuals. Without contextualising Dr Plaistow’s slide, it is very easy to see a focus on gendered individuals. It displays very specific triggers well known by sociologists and anthropologists of science who have researched how culturally gendered environments shape the interpretation of biology. Let’s just cite this hit of gender studies by Emily Martin: “The Egg and the Sperm: How Science has Constructed a Romance Based on Stereotypical Male-Female Roles”.
But, listening to Dr Plaistow’s talk and other talks during that session on inclusive inheritance, I was invited to think about environments shaping individuals across generations, not the other way around. So, I added to the conversation with my pregnant colleague that, in the context of that talk, the main message was not about maternal responsibility at all. I was amazed by the interpretative switch my colleague made in a blink of an eye: “OK so I’m trying to interpret the slide. It’s becoming a very compelling past-time. Does the slide mean that environmental factors affecting the egg can then be passed to the next generation via epigenetic phenomena?” Well, it is what I thought too.
In the course of twenty minutes, my presence in the room was an exercise in reinterpreting human reproduction through “water-fleas”, and connecting back to Lamarck’s Giraffes, as I heard the last talk by Martin Lind, from Uppsala University in Sweden. His laboratory created climate change in vitro and tested phenotypic variations over 80 generations of worms belonging to a species called: Caenorhabditis remanei. Preliminary results of data analysis on 30 generations suggest that climate change affects the “life-history” of worms, especially “ageing”.
Scaling up in a twirling shift, I started to reflect on “anthropogenic stressors” and was amazed that the effects of huge environmental changes can become questions to be asked in the cells of organisms. Or, to come back to my high school giraffes: What about their long necks (and empty stomach) if no leaf is to be found on top of trees anymore because of climate change induced drought?
A lot is being discussed around non genetic inheritance and whether it has a key role in adaptation or not. But data are still missing and many compelling ideas must be tested to show biological mechanisms. What appears to be also very clear is that interdisciplinary conversations will be of great interest for this generation of scholarship, and probably for many more to come.
 Janelle Lamoreaux (2016) summarises epigenetics this way: “Epigenetic research often studies the way in which DNA expression is influenced by extragenetic factors that might have previously been deemed social or environmental, and therefore insignificant to genetic processes. Diet, lifestyle, class, toxic exposures, and other variables once thought to be genetically noninfluential are today believed to play an important role in DNA expression. Epigenetics is often characterized as the study of modifications to the gene that impact gene expression without altering DNA sequence. Moreover, these modifications are sometimes inherited, which has led many to highlight the overlap of current epigenetic theories with Lamarckian ideas about the inheritance of acquired characteristics.”
 Edith Heard and Robert A. Martienssen, 2014, Transgenerational Epigenetic Inheritance: Myths and Mechanisms, Review, Cell, volume 157, issue 1, pp.95-109.
 Lamoreaux, Janelle. 2016. “What If the Environment Is a Person? Lineages of Epigenetic Science in a Toxic China”. Cultural Anthropology 31 (2), 188-214.
 Emily Martin, 1991, The Egg and the Sperm: How Science has Constructed a Romance Based on Stereotypical Male-Female Roles, Signs: Journal of Women in Culture and Society, 16:3, 485-501