Biology subjects

France, J. M.

Publications and source records attributed to France, J. M..

4 recordsLinked to original sources

bioRxiv2026

Trauma-Exposed Adolescents Show Reduced Cortical Glutamate Modulation during Inhibitory Control with Negative Emotional Stimuli

BackgroundChildhood trauma exposure (TE) may heighten negative emotional responses, overwhelm cognitive control, and increase risk for anxiety disorders. Cognitive control is facilitated by glutamatergic (Glu) excitatory neurotransmission within the dorsal anterior cingulate cortex (dACC). Dynamic changes in dACC Glu levels were investigated using {superscript 1}H functional magnetic resonance spectroscopy (1H fMRS) to assess the impact of negative emotional processing on neural mechanisms supporting cognitive control in TE-youth. MethodsFifty adolescents were categorized into two TE-Groups: Higher (Mtrauma=6{+/-}1events) and Lower (Mtrauma=3{+/-}1events). 1H fMRS from the dACC was acquired during an inhibitory motor control task requiring tapping responses to stimuli under two Response Modes, "NonSelective" (100% response) and "Selective" (80% response, 20% inhibition), executed with two Stimuli Conditions, "Squares" (no emotion) and "Faces" (emotion). Glu modulation (relative to basal levels) was tested across TE-Group, Stimuli Condition, and their interaction. Within each Stimuli Condition, Glu modulation was tested across Response Modes by TE-Group. ResultsWe observed a 2-way interaction of TE-Group x Stimuli Condition ({chi}2=4.66, p=0.031). Post-hoc tests revealed significantly lower Glu modulation in Higher TE vs Lower TE (p=.023) during Faces but not Squares. This Glu modulation did not differ across Response Modes. Within the Higher TE-Group, Glu was significantly reduced during Faces compared to Squares (p<.001). Basal dACC Glu levels did not differ between groups. ConclusionsTE-Group differences in adolescent dACC Glu modulation were observed during cognitive control performed with emotional, but not non-emotional, stimuli, highlighting the value of 1H fMRS for detecting trauma-related differences in task-related excitatory neurochemical dynamics.

neuroscience↗

bioRxiv2025

Target capture sequencing provides insights into hybridogenetic water frogs

The European water frogs of the genus Pelophylax, with their propensity to hybridize and a non-orthodox inheritance system in some hybrids, present a genetic puzzle that has previously lacked strong genomic tools. This has limited investigation into the remarkable hybridogenetic system observed in the edible frog P. esculentus as well as inhibited monitoring of invasive populations in a genus that is critically vulnerable to this threat. In this study we explore whether a previously developed target capture bait set, FrogCap, can be used to answer genomic questions within the genus, by applying it to the three taxa of Pelophylax native to the Netherlands. We observe that the target capture data cleanly separates the three taxa, confirming significant introgression of P. lessonae mtDNA into P. ridibundus from the Netherlands. We also show that target capture is an efficient method for identifying polyploidy in P. esculentus and is effective at determining ancestral contribution within our sample population. Targeted sequence capture using FrogCap is a useful tool to unravel the intricate evolution of Pelophylax water frogs.

genomics↗

bioRxiv2024

Identification of Y-chromosome turnover in newts fails to support a sex chromosome origin for the Triturus balanced lethal system

Non-recombining regions of the genome often have profound effects on evolution, resulting in phenomena such as sex chromosomes and supergenes. Amongst the strangest examples are balanced lethal systems, such as that found in newts of the genus Triturus. These systems halve reproductive output, and the evolution of such a deleterious trait is difficult to explain. For Triturus an intriguing model proposes that the balanced lethal system evolved from an ancestral Y-chromosome. To test this hypothesis, we identify the Y-chromosome of Triturus and verify whether it, or the balanced lethal system, is homologous to the Y-chromosome of its sister genus Lissotriton, which does not possess the balanced lethal system. We identify a set of candidate Y-linked markers in T. ivanbureschi and place them on a high-density linkage map that we construct with 7,233 RADseq markers. We validate male specificity of the markers across the genus, and then place both the Triturus and Lissotriton Y-linked regions within previously constructed target capture linkage maps that include genes linked to the balanced lethal system. We observe that neither the Triturus balanced lethal system, nor the Triturus Y-chromosome are homologous to the Lissotriton Y-chromosome. This is the first molecular evidence of a transition between Y-chromosome systems within salamanders. However, unless additional sex chromosome turnover events are involved, our data does not support a sex chromosome origin of the balanced lethal system.

evolutionary biology↗

bioRxiv2024

Genomic evidence suggests the balanced lethal system in Triturus newts originated in an instantaneous speciation event.

Triturus newts are afflicted by a balanced lethal system causing the spontaneous death of half of their offspring. How could such a maladaptive trait evolve? We construct genetic maps for Triturus and its sister genus Lissotriton, identifying genes involved in the balanced lethal system. Triturus chromosome 1 has diverged into two versions, which each carry a single massive deletion that is compensated for by duplication of the same region in the alternate version - indicating that the balanced lethal system arose instantaneously, in a single macromutation. Simulations show that, counterintuitively, the deleterious nature of the rearranged chromosomes protects them against competition with the ancestral arrangement via reproductive isolation. We conclude that the origin of the Triturus balanced lethal system also led to instantaneous speciation.

evolutionary biology↗