Biology subjects

Raymond, M.

Publications and source records attributed to Raymond, M..

8 recordsLinked to original sources

bioRxiv2026

Lack of Evidence for Local Adaptation in Risk Tolerance: A Genetic Study in Northern Senegal.

Risk tolerance is influenced by both environmental and genetic factors and may be shaped by local selective pressures in hazardous environments. In Northern Senegal, fishermen from the village of Guet Ndar are chronically exposed to high occupational mortality risk, making this population a potential model for local adaptation to risky environments. In a previous study, we showed that men from this fishing community were less risk-tolerant than men from a nearby farming village, although this difference could not be explained by variation at the DRD4 locus. Here, we investigated whether genetic variants previously associated with general risk tolerance in large genome-wide association studies (GWAS) exhibit signals of local adaptation in these Senegalese populations. We genotyped 44 candidate SNPs in 373 individuals sampled from the risky fishing area and the non-risky farming area. Population genetic analyses revealed extremely low and non-significant differentiation between the two populations (mean FST = 0.0003, p = 0.33), indicating that the two groups are genetically indistinguishable at these loci. Furthermore, none of the candidate SNPs showed a significant association with experimentally measured risk tolerance after correction for multiple testing. These results provide no evidence that local adaptation for risky behavior has occurred, several explanations may account for this negative result.

evolutionary biology↗

bioRxiv2026

The role of miscarriage and sororal birth order in male same-sex orientation: Theoretical predictions and empirical data

This study explores the proximal and biological mechanisms underlying male same-sex orientation, with a focus on the Fraternal Birth Order Effect (FBOE), a robust phenomenon whereby same-sex oriented men tend to have more older brothers than the population average, and its relationship with the Sororal Birth Order Effect (SBOE), whereby older sisters also appear to influence sexual orientation, albeit less consistently. The Maternal Immune Hypothesis (MIH), which posits that maternal immune responses to male-specific antigens accumulate across successive male pregnancies, provides a compelling proximal explanation for the FBOE, but it fails to fully account for the SBOE and other birth order patterns, such as the elevated prevalence of same-sex orientation among only-children compared to firstborns in larger sibships. Through explicit modelling of the MIH, our simulations reveal that the correlation between the number of older brothers and sisters generates a spurious SBOE, which disappears when controlling for older brothers. However, this control becomes insufficient when miscarriages are included in the simulations. Additionally, the increased prevalence of same-sex orientation among only-children, relative to firstborns with siblings, only emerges when miscarriages are incorporated into the model. Empirical analyses across eight diverse populations (Indonesia, France, French Polynesia, Greece, Canada, Czech Republic, Samoa, Iran) confirm the presence of an overall significant FBOE and, critically, an overall significant SBOE even after controlling for the number of older brothers. The higher frequency of same-sex orientation men among only-children, compared to firstborns in larger sibships, supports a possible role of miscarriage for this SBOE. However, the estimated miscarriage rates (37% - 58%) explaining the observed SBOE slightly exceeds reported rates (30% - 45%) which conservatively include early pregnancy losses. This possibly suggests that additional mechanisms contribute to a spurious SBOE or that a genuine SBOE coexists with the FBOE. Limitations of this study are discussed, as well as whether the MIH framework can be extended to accommodate these findings, or if alternative explanations are needed to resolve these discrepancies.

evolutionary biology↗

bioRxiv2024

A proximity ligation screen identifies SNAT2 as a novel target of the MARCH1 E3 ubiquitin ligase

E3 ubiquitin ligases are part of various families of proteins and include hundreds of members, which play key roles in all aspects of cell biology. They generally regulate the half-life of other proteins but can also modulate their cellular localization and functions. The MARCH family of ubiquitin ligases is composed of 11 members and two closely related proteins, MARCH1 and MARCH8, share similar targets, while being active in different cell types. Although they appear to target principally immune cell components, such as MHC class II molecules and the co-stimulatory molecule CD86, the repertory of their targets remains to be fully documented. Here, to further define the MARCH1s interactome, we adapted a proximity-dependent biotin identification (BioID)-based screening approach in live HEK293 cells. We transfected a fusion protein consisting of mouse MARCH1 linked to YFP at its N-terminus and to the biotin ligase of Aquifex aeolicus at its C-terminus. Upon transient overexpression of this construct in the presence of exogenous biotin, we could recover biotinylated proteins that are presumably found within 10nm of MARCH1. To help in the identification of bona fide down-regulated specific targets, we compared MARCH1s interactome with the one obtained using a ubiquitination-deficient MARCH1 mutant (MARCH1W104A). CD98 and CD71, two previously described targets of MARCH1, were identified in this screen. Of 16 other biotinylated proteins identified by semi-quantitative mass spectrometry, 10 were tested directly by flow cytometry to monitor their expression in the presence or absence of transfected MARCH1. The protein levels of five of these endogenous targets, CD29, CD112, NKCC1, CD147 and SNAT2, confirmed their negative regulation by MARCH1 in this system. SNAT2 was particularly sensitive to the presence of MARCH1 and was found to be ubiquitinated on Western blots following immunoprecipitation. Thus, BioID2 is an effective mean of characterizing the interactome of MARCH1 and the identification of SNAT2 suggests a role of this ubiquitin ligase in cellular metabolism.

immunology↗

bioRxiv2023

From natural to sexual selection: Revealing a hidden preference for camouflage patterns

Background-matching visual patterns are selected to minimize detection by predators. However, once detected, what effects do these patterns have on conspecific perception? In humans, considerable evidence supports a "processing bias" by which people prefer images that match the spatial statistics of natural scenes, likely because the brain has evolved, or develops, to process such scenes efficiently. A direct but untested prediction of this bias is that people should prefer background-matching patterns compared to similar patterns that mismatch the spatial statistics of their surroundings. We conducted an online experiment to test this prediction on over 1700 participants. Our results show that a preference for the most frequent value of Fourier slope (a measure of spatial structure) observed in natural scenes can be modulated by an additional preference for background-matching. Because the initial stages of perception that underlie the efficient processing of visual scenes are widely conserved among animals, especially vertebrates, we expect this preference for background-matching patterns to be shared by other organisms. Two overlooked potential implications are that some animals may choose display sites with spatial statistics matching their own phenotype, and that the evolution of visual signals will, variously, be constrained or facilitated by such preferences for background-matching patterns. Highlights- Processing bias aims to explain the origins of preference for sexual signals - It predicts visual properties of background-matching patterns make them attractive - An online experiment with over 1700 human participants confirms that prediction - Results have important implications for the preference and design of animal signals

evolutionary biology↗

bioRxiv2022

From proteins to nanoparticles: domain-agnostic predictions of nanoscale interactions.

The accurate and rapid prediction of generic nanoscale interactions is a challenging problem with broad applications. Much of biology functions at the nanoscale, and our ability to manipulate materials and engage biological machinery in a purposeful manner requires knowledge of nano-bio interfaces. While several protein-protein interaction models are available, they leverage protein-specific information, limiting their abstraction to other structures. Here, we present NeCLAS, a general, and rapid machine learning pipeline that predicts the location of nanoscale interactions, providing human-intelligible predictions. Two key aspects distinguish NeCLAS: coarsegrained representations, and the use of environmental features to encode the chemical neighborhood. We showcase NeCLAS with challenges for protein-protein, protein-nanoparticle and nanoparticle-nanoparticle systems, demonstrating that NeCLAS replicates computationally- and experimentally-observed interactions. NeCLAS outperforms current nanoscale prediction models and it shows cross-domain validity. We anticipate that our framework will contribute to both basic research and rapid prototyping and design of diverse nanostructures in nanobiotechnology.

bioinformatics↗

bioRxiv2022

Increased birth rank of homosexual males: disentangling the older brother effect and sexual antagonism hypothesis

Male homosexual orientation remains a Darwinian paradox, as there is no consensus on its evolutionary (ultimate) determinants. One intriguing feature of homosexual men is their higher male birth rank compared to heterosexual men. This can be explained by two non-exclusive mechanisms: an antagonistic effect (AE), implying that more fertile women have a higher chance of having a homosexual son and to produce children with a higher mean birth rank, or a fraternal birth effect (FBOE), where each additional older brother increases the chances for a male embryo to develop a homosexual orientation due to an immunoreactivity process. However, there is no consensus on whether both FBOE and AE are present in human populations, or if only one of these mechanisms is at play with its effect mimicking the signature of the other mechanism. An additional sororal birth order effect (SBOE) has also recently been proposed. To clarify this situation, we developed theoretical and statistical tools to study FBOE and AE independently or in combination, taking into account all known sampling biases. These tools were applied on new individual data, and on various available published data (two individual datasets, and all relevant aggregated data). Support for FBOE was apparent in aggregated data, with the FBOE increasing linearly with fertility. The FBOE was also supported in two individual datasets. An SBOE is generated when sampling in presence of FBOE, suggesting that controlling for FBOE is required to avoid artefactual SBOE. AE was not supported in individual datasets, including the analysis of the extended maternal family. The evolutionary implications of these findings are discussed.

evolutionary biology↗

bioRxiv2019

Activation of MAIT cells plays a critical role in viral vector vaccine immunogenicity

Mucosal-associated invariant T (MAIT) cells can be activated by viruses through a cytokine-dependent mechanism, and thereby protect from lethal infection. Given this, we reasoned MAIT cells may have a critical role in the immunogenicity of replication-incompetent adenovirus vectors, which are novel and highly potent vaccine platforms. In vitro, ChAdOx1 (Chimpanzee Adenovirus Ox1) induced potent activation of MAIT cells. Activation required transduction of monocytes and plasmacytoid dendritic cells to produce IL-18 and IFN-, respectively. IFN--induced monocyte-derived TNF- was identified as a novel intermediate in this activation pathway, and activation required combinatorial signaling of all three cytokines. Furthermore, ChAdOx1-induced in vivo MAIT cell activation in both mice and human volunteers. Strikingly, MAIT cell activation was necessary in vivo for development of ChAdOx1-induced HCV-specific CD8 T cell responses. These findings define a novel role for MAIT cells in the immunogenicity of viral vector vaccines, with potential implications for future design.\n\nOne sentence summaryRobust immunogenicity of candidate adenovirus vaccine vectors requires the activation of unconventional T cells.

immunology↗

bioRxiv2017

Females prefer cooperative males even when cooperative behavior is unobserved: evidence from the mound-building mouse, Mus spicilegus

Theoretical and empirical studies in humans suggest that cooperative behaviors may act as signals during mate choice. However, cooperation is not always observable by potential partners before mate choice. To address whether cooperative phenotypes are preferred based on cues different from cooperative behaviors per se, we designed an experimental paradigm using wild-born mound-building mice (Mus spicilegus), a species with biparental care. In this species, females cannot observe male cooperative behaviors: mate choice occurs in the spring, whereas mounds are cooperatively built in the fall. We first assessed the variation in mound building investment and identified males exhibiting high and low amounts of cooperation. Second, we presented these males to females during two-way choice tests. As offspring survival relies on mound protection, we hypothesized that mound building could be a form of paternal care and assessed whether cooperative males were more involved in offspring attendance using pup-retrieval experiments. Our results indicate that females were more attracted to highly cooperative males over less cooperative, even when they did not observe them build. This finding suggests that female mate choice is influenced either by cues of cooperativeness different than cooperative behaviors or by preferences for traits associated with cooperativeness. Moreover, male offspring attendance was negatively correlated with cooperativeness, suggesting the potential existence of two alternative paternal strategies in offspring care (mound building versus offspring attendance). Overall, our findings support the existence of preference for cooperative phenotypes in a non-human species and suggest that sexual selection might be involved in the evolution of cooperation.

animal behavior and cognition↗