Authors: Thomas, Frédéric; Hamant, Olivier; Lecointre, Guillaume; Poulin, Robert; Selosse, Marc-André; Massol, François; Asselin, Klara; Madsen, Thomas; Ujvari, Beata; Dujon, Antoine M.; Boutry, Justine; Loreau, Michel; Capp, Jean-Pasca

Source: Peer Community Journal (Jul 2026)

Abstract

Darwinian selection (DS), based on heritable variation and differential reproductive success, is central to evolutionary theory. However, many systems in biology, including prebiotic molecular networks, microbial communities, and tumors, persist and exhibit structured dynamics despite lacking clear reproduction or lineage-based inheritance at the relevant level.

Building on, but also critically refining, the concept of selection for function (SF) proposed by Wong et al. (2023), we argue that SF provides a complementary descriptive framework for interpreting such systems. Rather than offering an alternative causal explanation to Darwinian processes, SF emphasizes the differential persistence of functionally coherent configurations over time.

Its main value is heuristic and integrative: it makes persistence-based patterns explicit across systems in which lineage-based descriptions are incomplete, diffuse, or difficult to apply at the focal scale. Although in many biological contexts, the emergence and maintenance of traits are well explained by established Darwinian frameworks (e.g., kin selection, multilevel selection, or mutation–selection dynamics), SF highlights how system-level organization and persistence shape long-term outcomes.

Through examples including seed dormancy, sexual reproduction, symbioses, biofilms, and tumor organization, we illustrate how configurations that may be costly or neutral at the individual level can nevertheless contribute to system-level stability and persistence. SF is particularly informative in systems where reproduction and inheritance are weak, diffuse, or difficult to define, but it remains compatible with Darwinian dynamics when these are present.

By making persistence-based filtering explicit, SF complements existing evolutionary frameworks and provides an additional lens for interpreting complex, multilevel, and non-replicating systems.

Authors: Nina Casillas , Bent Petersen , Sarah L F Martin , Kjeld Henrik Ophus , Henrik Bringsøe , Jaelle C Brealey , Vanessa C Bieker , Jaime Morin-Lagos , Dag Dolmen , Thomas Madsen , Rasmus Nielsen , Morten E Allentoft , José Cerca , Michael D Martin

Source: Genome Biology And Evolution (Jun 2026)

Abstract

Color polymorphism is an important trait due to its role in defense strategies, feeding habits, environmental responses such as temperature regulation, and overall fitness. While the genetic basis of color polymorphism is well understood in mammals, it remains relatively understudied in nonavian reptiles. Vipera berus, the European adder, is the most widely distributed and northernmost terrestrial snake in the world.

Similar to other European vipers, V. berus exhibits a range of dorsal color patterns spanning from zig-zag to complete melanism. However, a unique longitudinal dorsal stripe pattern was recently discovered in the isolated Gossa Island (∼45 km_²) population of Norway, where ∼5% of snakes exhibit this distinct pattern instead of the common dorsal zig-zag pattern.

In this study, we investigated the genetic basis of the unique phenotype observed on Gossa by combining low-depth whole-genome shotgun sequencing and pairwise F_ST genome scanning. We discovered a moderately sized, significantly differentiated genomic region containing five associated genes, including the premelanosome gene (PMEL) that encodes a well-known transmembrane glycoprotein that is a key component of melanosome organelles. We implicate a functionally relevant variant in the encoded premelanosome protein.

Our results provide insight into the evolution and genetic basis of pigmentation of squamate reptiles using the unbiased approach of genome scanning, a method that has rarely been used in this context.

Authors: Timothy M Smith, Georgina Bramwell, Eric A Treml, Paul H York, Peter I Macreadie, D Jeff Ross, Michael J Keough, Craig D H Sherman

Source: Annals Of Botany (Jan 2026)

Abstract

Background and Aim: Many plants have complex mating systems involving sexual and asexual reproduction. Investment in different reproductive strategies can vary among sub-populations and is linked to local ecological conditions, but the key drivers are not well understood. We aimed to use direct estimates of reproductive investment (flowering and seed production), population genetic surveys and a biophysical model to assess the relationship between connectivity and the relative importance of sexual and asexual reproduction in maintaining seagrass populations. We predicted that populations with high levels of connectivity and investment in flowering and seed production will display higher levels of genotypic diversity, while more isolated populations with lower investment in flowering and seed production will display higher levels of clonality.

Methods: We combined field surveys of flowering and seed production with population genetic surveys and a biophysical dispersal model to assess reproductive effort and patterns of connectivity in the seagrass Heterozostera nigricaulis across 16 sites in a large embayment in south-eastern Australia.

Key Results: Estimates of genotypic diversity varied widely between locations, ranging from highly clonal (R = 0.18) to highly diverse (R = 0.91). Genotypic diversity correlated strongly with local seed production and the inflow of propagules derived from the biophysical dispersal model (pseudo-R² = 0.73). Sites that receive low numbers of propagules and produce few seeds were more clonal than sites with high propagule inflow and seed density.

Conclusions: These results show that isolated populations have higher levels of clonality and invest less in sexual reproduction. This has important consequences for the managing of declining populations of seagrass where fragmentation and loss of key source populations of propagules may lead to declines in genotypic and genetic diversity and the long-term viability of these important habitat-forming species.

Authors: Frédéric Thomas, Antoine M. Dujon, Daniel Vaiman, Gerard Eberl, Catherine Alix-Panabières, Pascal Pujol, Beata Ujvari, Jordan Meliani, Aurora M. Nedelcu, Jean-Pascal Capp

Source: Evolutionary Applications (Feb 2026)

Abstract

Pathological processes are often conceptualized as localized phenomena anchored in a primary tumor, a focal lesion, or a single organ. However, growing evidence indicates that many diseases persist and progress as complex distributed systems, maintained by interactions among multiple sites. Building on the emerging framework of selection for function, which can be applied to understand the evolutionary persistence of both replicating and non-replicating entities, we propose that metastases, amyloidoses, fibroses, autoimmune syndromes, granulomatous diseases, and multifocal reproductive disorders can all be understood as complex evolving pathological systems within individuals.

In these contexts, local units such as metastatic nodules, amyloid plaques, or fibrotic foci act as semi-autonomous entities, yet achieve collective persistence through systemic flows, feedback loops, and network-level interactions, where local structuration gives rise to systemic effects. At certain points, lesions that produce mediators can trigger systemic alterations that, in turn, favor the emergence and persistence of additional lesions.

This creates a vicious cycle in which local and systemic dynamics reinforce one another, helping these specific pathological networks to overcome host defense mechanisms and persist (i.e., be ‘selected’ via differential persistence). This perspective unifies seemingly disparate conditions under the principle of system persistence, reframing pathology as an emergent organizational property of a pathological system rather than as isolated local breakdowns of organismal components. It also carries important implications for evolutionary medicine, suggesting a taxonomy of diseases that distinguishes localized from distributed functional pathologies. Clinically, it underscores the need to go beyond focal interventions, advocating instead for therapies that disrupt pathological connectivity, destabilize network coherence, and monitor systemic biomarkers of disease persistence.

Recognizing the role of selection for function in the emergence and persistence of complex pathological systems opens new avenues for both theoretical integration and therapeutic innovation in evolutionary medicine.

Authors: Anne-Lise Gérard, Florence Pirard, Caitlin Vanbeek, Antoine M. Dujon, Aaron G. Schultz, Rodrigo K. Hamede, Hannah V. Siddle, Frédéric Thomas, Matthew McKenzie, Mark D. Ziemann, Beata Ujvari

Source: The Febs Journal (Jan 2026)

Abstract

Devil Facial Tumour Diseases (DFTD), threatening Tasmanian devils, consist of two distinct transmissible cancers, DFT1 and DFT2, with differing origins and geographic spread. We investigated the metabolic differences between DFT1 and DFT2, examining cell viability, metabolic outputs, and bulk gene expression.

Using both DFT1 and DFT2 cell lines and biopsies, we found that glycolysis, oxidative phosphorylation, glutamate metabolism, and fatty acid synthesis are all essential for the survival of both tumour types. However, DFT2 exhibited higher rates of glycolysis and lactate generation compared to DFT1.

This coincided with elevated ATP production, cholesterol biosynthesis, and ROS generation, as well as an increased reliance on fatty acid metabolism. Furthermore, DFT2 is less metabolically adaptable than DFT1, being unable to switch to oxidative phosphorylation as DFT1 can when required. These metabolic changes in DFT2, in conjunction with its higher growth rate, suggest a more aggressive cancer phenotype than DFT1.

Our findings highlight distinct metabolic adaptations in DFT2 that may contribute to its competitive advantage.

Authors: Luca Luiselli, Thomas Madsen

Source: African Journal Of Ecology (Jan 2026)

Abstract

The ongoing biodiversity crisis is driven primarily by habitat degradation and accelerating climate change, with extreme climatic events increasingly shaping population dynamics across taxa. Detecting and interpreting these effects requires long-term ecological studies, yet such datasets remain rare, including Africa where biodiversity is high and ecological systems are strongly influenced by climatic variability and human land use.

Here we synthesise evidence demonstrating why short- and even medium-term studies often fail to capture the demographic consequences of climate change, especially those driven by rare but severe events such as droughts and floods. Drawing on case studies from temperate and tropical systems—including predator–prey collapses, reptile population crashes and iconic long-term projects such as Gombe and Amboseli—we show how sustained monitoring has transformed ecological understanding and conservation priorities.

We emphasise that Africa’s ecological complexity and prevalence of long-lived species make long-term, population-focused research particularly critical. However, funding structures and institutional constraints frequently undermine continuity. To address this gap, we propose an integrative framework combining targeted long-term ecological research funding, institutional support for data continuity, community-based monitoring and local ecological knowledge, and the integration of diverse data sources.

We argue that long-term monitoring is not a luxury but a scientific and ethical necessity for effective conservation under rapid environmental change.

Authors: Nikita Stepanskyy; Jordan Meliani; Jácint Tökölyi; Aurora M. Nedelcu; Pascal Pujol; Beata Ujvari; Frédéric Thomas; Antoine M. Dujon

Source: Proceedings Of The Royal Society B-biological Sciences (Aug 2026)

Abstract

Reproduction is a key life-history trait but often comes at the expense of somatic maintenance, including ageing and susceptibility to disease. While reproduction–immunity trade-offs have been experimentally demonstrated in the context of infectious diseases, whether reproduction similarly undermines susceptibility to tumours has remained unclear.

Using the freshwater cnidarian Hydra oligactis, in which tumours arise spontaneously and reproductive effort can be experimentally modulated through food availability, we tested the possibility of a trade-off between reproduction and tumour dynamics. Higher reproductive effort increased the likelihood of tumour development, reduced the probability of remission and increased the likelihood of progression to advanced stages. Resource availability modulated the strength of the trade-off in terms of tumour risk and remission, whereas tumour severity was determined solely by reproductive effort.

Together, these findings provide rare empirical support for a trade-off between reproduction and tumour dynamics, demonstrating that reproductive investment compromises both tumour prevention and control and that its expression can be shaped by environmental conditions. More broadly, they suggest that cancer susceptibility in more complex lineages may instead reflect evolutionary trade-offs that prioritize reproduction over somatic maintenance, helping illustrate one mechanism by which evolutionary trade-offs contribute to the persistence of cancer and to variation in susceptibility across taxa.

Authors: Beichen Yang, Matthew K. Jago, Thomas S. Mock, Barney M. Hines, Michael J. Salini, Giovanni M. Turchini, Richard P. Smullen, Nynke Raven, David S. Francis

Source: Aquaculture (Dec 2025)

Abstract

Dietary choline plays a functional role in lipid metabolism of Atlantic salmon. Fillet and visceral adipose tissue have been considered as the primary sites for lipid and energy storage. Currently, the effects of dietary choline inclusion on lipid metabolism, particularly triacylglycerol storage and metabolism in visceral adipose tissue of Atlantic salmon, remain poorly understood. To test this, four diets were formulated and manufactured with graded levels of choline (2.5, 3.3, 4.4, and 5.2 mg/g diet) and fed to juvenile Atlantic salmon for 124 days.

This study showed that the impact of dietary choline concentration on lipid deposition was primarily reflected in the visceral adipose tissue instead of the fillet. In visceral adipose tissue, both triacylglycerol and phosphatidylcholine concentration responded quadratically as dietary choline concentration increased (P < 0.05), however, these two lipid classes were negatively correlated (P < 0.05). Regression revealed that both the highest (5.2 mg/g) and lowest levels of dietary choline (2.5 mg/g) accumulated higher triacylglycerol associated with adipocyte hypertrophy in visceral adipose tissue relative to moderate inclusion levels.

The highest level of dietary choline tested (5.2 mg/g) demonstrated enhanced diacylglycerol acyltransferase-dependent triacylglycerol synthesis, however, this was accompanied by the lowest protein, energy and dry matter digestibility. The inclusion level of 2.5 mg/g dietary choline was considered deficient for Atlantic salmon, given the prevalence of visceral adiposity and growth retardation, accompanied by the lowest apparent choline digestibility.

This study highlights the impact of dietary choline levels on triacylglycerol storage and metabolism in the visceral adipose tissue of Atlantic salmon.

Authors: Antoine M. Dujon, Jonas Courtalon, Anna Miltiadous, Maci Blake, Beata Ujvari, Peter A. Biro, Frédéric Thomas

Source: Iscience (Nov 2025)

Abstract

Oncogenic pressures, factors that increase tumor risk, are intensifying with human-driven environmental change, yet their ecological effects remain mainly unquantified.

We examined how UVB-induced oncogenic stress affects interactions between two Australian freshwater planaria: the globally invasive predator Girardia tigrina and the native prey Cura pinguis. We hypothesized that DNA damage could either heighten prey vulnerability or impair predator performance.

Native planaria showed less UVB-induced DNA damage, likely due to darker pigmentation, while damage in G. tigrina reduced predation rates, suggesting energetic costs of DNA repair. UVB also reduced movement in both species, with partial recovery in the invasive species but prolonged immobility in the native. Additionally, UVB strongly suppressed asexual reproduction in G. tigrina, indicating trade-offs between DNA repair and proliferation.

These results reveal that oncogenic stress can reshape species interactions and invasion dynamics, underscoring the need to integrate cancer ecology into conservation and invasion biology.

Authors: Frédéric Thomas, Antoine M. Dujon

Source: BioEssays (Dec 2025)

Abstract

Laplane et al. recently provided a valuable framework for understanding cancer evolution through multilevel selection (MLS), distinguishing between MLS1, where groups differ in persistence based on the traits of their constituent cells but do not reproduce or evolve group-level adaptations, and MLS2, where groups themselves reproduce and possess emergent fitness distinct from that of individual cells. However, as the authors themselves acknowledge, applying MLS2 to metastasis is challenging for several reasons.

We argue that, rather than behaving as isolated evolutionary units, tumor sites function as components of a distributed system. This perspective suggests that metastasis may be better understood through the lens of selection for function, a framework that explains how traits contributing to system-level persistence can be maintained without requiring group-level reproduction.

This approach complements MLS theory and helps account for the resilience of the metastatic system as a whole, namely, the persistence and coordination of multiple tumor sites functioning as a collective rather than as isolated tumors, beyond classical Darwinian models.

It also aligns with the view that metastasis may reflect the reactivation of ancient cellular programs in a novel, nonreproductive context.