Biology subjects

Dore, M.

Publications and source records attributed to Dore, M..

6 recordsLinked to original sources

bioRxiv2026

Defective HIRA driven chromatin maintenance underlies age related decline in oocyte quality

The rapid fertility decline in women over 35 years of age has been attributed to decreasing oocyte quality. Aging oocytes accumulate DNA damage, chromosome segregation defects and altered epigenetic modifications. Critically, the molecular mechanisms underlying these changes remain poorly understood. Here we uncovered that in the mouse, the HIRA driven H3.3 histone replacement is attenuated during oocyte aging leading to the loss of chromatin homeostasis. The loss of HIRA function is caused by its SUMOylation resulting in the disruption of HIRA-UBN1-CABIN1 complex and its association with chromatin. We further show that preventing HIRA SUMOylation restores H3.3 incorporation and chromatin integrity in aged mouse oocytes leading to improved oocyte maturation and preimplantation development rates. Importantly, similar chromatin homeostasis defect is observed in aging human oocytes pointing towards a conserved process. Our findings provide novel insights into the molecular mechanisms underlying age-related oocyte quality decline and pave the way for clinical interventions.

developmental biology↗

bioRxiv2026

Decoupled wing evolution reveals trait-specific links between morphology, geography, and diversification in Ithomiini butterflies.

Understanding when species diversification and phenotypic evolution are coupled remains a central challenge in macroevolution. Such coupling may depend on the traits considered, phenotypic integration, or the geographic context in which diversification occurs. Here, we investigate these relationships in Ithomiini, a diverse Neotropical butterfly tribe whose diversification is strongly associated with the Andes-Amazonia system. We quantified forewing and hindwing size and shape for 1,618 individuals representing 291 species using geometric morphometrics, and combined these data with phylogenetic comparative methods, diversification-rate estimates, and spatial analyses of species distributions. Evolutionary rate shifts were largely trait- and wing-specific, indicating limited coupling between forewing and hindwing evolution. Across the phylogeny, wing size evolution and extant wing size were not associated with species diversification, nor was hindwing shape evolution. By contrast, forewing shape evolutionary rates showed a positive association with diversification. Spatial analyses revealed that this coupling was geographically concentrated in the Andes, where high diversification rates coincided with elevated forewing size and shape diversity and increased forewing evolutionary rates. Hindwing diversity, by contrast, more closely tracked phylogenetic diversity and showed weaker or opposing relationships with diversification. Our results show that diversification and phenotypic evolution in Ithomiini are neither generally coupled nor fully independent, but linked in trait-specific and geographically structured ways. More broadly, they highlight the need to decompose complex phenotypes and integrate spatial context when testing macroevolutionary coupling.

ecology↗

bioRxiv2025

Perceptual maps reveal rampant convergence in butterfly wing patterns across the Neotropics

In 1879, Fritz Muller formulated the first mathematical evolutionary model to explain mutualistic mimicry between coexisting defended prey. Yet, whether local mimicry drives the structure of aposematic prey signals across their entire geographic distribution remains untested because the perception of pattern similarity has never been assessed at large spatial scale. Here, we implement a citizen science survey to map, throughout the Neotropics, variation in the wing patterns of heliconiine butterflies (Nymphalidae) as perceived by vertebrate cognitive systems. We show that despite a continuum of perceived similarity in wing patterns at the continental scale, the convergence of sympatric species into discrete mimicry rings is ubiquitous among local communities. These results expand Mullers historical predictions by quantifying the rampant convergence of prey signals across an entire continent.

evolutionary biology↗

bioRxiv2025

Müllerian mimicry in Neotropical butterflies: One mimicry ring to bring them all, and in the jungle bind them

Understanding the mechanisms underlying species distributions and coexistence is essential to predict and prevent the impacts of global change, particularly in biodiversity hotspots. However, the effects of biotic interactions may be challenging to investigate at large spatial scales. Leveraging well-characterized Mullerian mimetic systems in Neotropical butterflies, we investigated spatial patterns of mutualistic mimetic interactions within and between two tribes of aposematic Nymphalid butterflies: the Heliconiini (Heliconiinae) and the Ithomiini (Danainae). Despite 85 My of independent evolutionary histories, many species share similar warning wing patterns across the Neotropics. In this study we show that both tribes form similar biodiversity hotspots with a high prevalence of rare species and mimetic patterns in the tropical Andes. However, we reveal a higher relative richness of heliconiine butterflies than ithomiines in the Amazon basin contrasting with the Andean concentration of ithomiine diversity. Despite this difference in broadscale diversity patterns, we also document large-scale spatial associations among phenotypically similar species within and between tribes, thereby providing new empirical evidence for Fritz Mullers historical model of mutualistic mimicry at a continental scale. Furthermore, comparative phylogenetic analyses suggest that co-mimetic species within and between tribes have converged towards similar climatic niches as a response to selection favoring co-occurrence. Our findings illustrate the strength of mutualistic interactions in shaping biodiversity patterns at continental scale and in supporting niche convergence even across millions of years of evolution. Critically, it also emphasizes the pervasive vulnerability of mimetic communities, bound by positive interactions, to disassembly induced by climate change. Significance statementMullerian mimicry is a remarkable example of convergent evolution driven by natural selection where coexisting prey species converge in their warning signal advertising their defenses to predators. Heliconiine and ithomiine butterflies found throughout Neotropical rainforests were instrumental in Fritz Mullers historical model, which provided the mechanism for such resemblance. Leveraging decades of fieldwork and museum collections, we show that species with similar color patterns present strikingly similar spatial distributions, regardless of how closely related they are. Such co-occurrence appears reinforced by the evolution of similar climatic requirements among look-alike species. Our findings emphasize the key role of mutualistic interactions in shaping large-scale patterns of biodiversity and supporting convergence in the climatic niches of species spanning across phylogenetically distant clades.

evolutionary biology↗

bioRxiv2020

Differences in mitochondrial activity trigger cell competition during early mouse development.

Cell competition is emerging as a quality control mechanism that eliminates unfit cells in a wide range of settings from development to the adult. However, the nature of the cells normally eliminated by cell competition and what triggers their elimination remains poorly understood. In mouse, prior to gastrulation 35% of epiblast cells are eliminated. Here we have performed single cell transcriptional profiling of these cells and find that they show the hallmarks of cell competition and have mitochondrial defects. We demonstrate that mitochondrial defects are common to a range of different loser cell types and that manipulating mitochondrial function is sufficient to trigger competition. Importantly, we show that in the embryo cell competition eliminates cells with mitochondrial DNA mutations and that even non-pathological changes in mitochondrial DNA sequence can induce cell competition. Our results therefore suggest that cell competition is a purifying selection that optimises mitochondrial performance prior to gastrulation.

developmental biology↗

bioRxiv2019

FACT mediates cohesin function on chromatin

Cohesin is a key regulator of genome architecture with roles in sister chromatid cohesion 1,2 and the organisation of higher-order structures during interphase 3 and mitosis 4,5. The recruitment and mobility of cohesin complexes on DNA is restricted by nucleosomes 6-8. Here we show that cohesin role in chromosome organisation requires the histone chaperone FACT. Depletion of FACT in metaphase cells affects cohesin stability on chromatin reducing its accumulation at pericentric regions and binding on chromosome arms. Using Hi-C, we show that cohesin-dependent TAD (Topological Associated Domains)-like structures in G1 and metaphase chromosomes are disrupted in the absence of FACT. Surprisingly, sister chromatid cohesion is intact in FACT-depleted cells, although chromosome segregation failure is observed. Our results uncover a role for FACT in genome organisation by facilitating cohesin-dependent compartmentalization of chromosomes into loop domains.

molecular biology↗