Biology subjects

Fernandez-Guiberteau, D.

Publications and source records attributed to Fernandez-Guiberteau, D..

3 recordsLinked to original sources

bioRxiv2025

Comparative microbiome analyses reveal differences between wild populations and captive groups of the Montseny Brook Newt (Calotriton arnoldi)

The Montseny brook newt, Calotriton arnoldi, is a Critically Endangered amphibian species endemic to the Montseny Massif in Catalonia, Northeastern Spain. Due to population declines and threats to its natural habitat, an ex-situ breeding program was initiated in 2007. A key goal of the program is to ensure the survival of captive-bred individuals after reintroduction, which in amphibians heavily relies on the specimens microbiome being capable of protecting them from environmental microorganisms, especially considering the global Chytridiomycosis pandemic caused by the fungi Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal). This study aims to characterize the microbiome of wild and captive specimens of Calotriton arnoldi, to identify differences in microbiome composition, and to determine their potential impact on captive-bred individuals upon reintroduction. Up to 7,438 ASVs (Amplicon Sequence Variants) were identified from 138 samples from 21 and 61 wild and captive-bred individuals, respectively. Results indicate that wild populations from different subspecies have significantly different microbiome composition, as do wild and captive-bred groups from the same subspecies. Additionally, dissimilarities in microbiome variability were only found within each subspecies, between wild and captive-bred groups. In terms of composition, certain bacteria were identified as potential markers for both wild and captive environments. Enhancing microbiome variability might improve the survival prospects of reintroduced specimens. Thus, exposing captive specimens to a more natural environment while in captivity or a soft-release procedure could potentially mitigate the absence of exposure to other bacteria and potential pathogens from their native environment.

microbiology↗

bioRxiv2025

Lizards on a sky archipelago: Genomic approaches to the evolution of the mountain genus Iberolacerta

The mountain-dwelling lizards of the genus Iberolacerta inhabit several isolated massifs across central and southwestern Europe. Their restricted and fragmented ranges, coupled with high altitude specialization in most species, entail a significant threat in the context of climate change for this group of lizards that has attracted interest from different fields. On the one hand, the alpine confinement of these relict species precedes the Pleistocene glacial cycles, and a few hypotheses have been proposed to explain it: from competitive exclusion by the wall lizards of the genus Podarcis, to adaptations to either cold or hypoxia, that would prevent them from expanding into lowlands. On the other hand, extensive research on chromosome evolution has shown Iberolacerta karyotypes to fairly differ from other lacertid lizards, exhibiting reductions in chromosome numbers and multiple sex chromosome determination systems. Here we present a chromosome-level genome assembly for Iberolacerta aurelioi, an Endangered rock lizard endemic to the Pyrenees. This genome has shed light on a genome architecture shaped by chromosome fusions, whose adaptive potential we discuss, as well as on expression shifts towards a hemoglobin isoform of enhanced oxygen affinity, as an adaptation to altitudinal hypoxia. In addition, medium coverage whole-genome sequencing data from 12 representatives encompassing all species and subspecies within the genus allowed us to address phylogenomic relationships, unveiling introgression events, gathering evidence in support of the competitive exclusion hypothesis through past demographic inference, and providing insights into homozygosity burdens, which offer valuable information for conservation efforts.

genomics↗

bioRxiv2024

Unveiling the evolutionary history of European vipers and their venoms from a multi-omic approach

Snake genomes attract significant attention from multiple disciplines, including medicine, drug bioprospection, and evolutionary biology, due to the unique features found in snakes, especially, the evolution of venom. However, genomic research within the family Viperidae has mostly focused to date on the subfamily Crotalinae, while overlooking Viperinae, the Old World vipers. Among Viperinae, European vipers (Vipera) have been the subject of extensive research because of their venoms, phylogeographic, and ecological diversification. Nevertheless, venom research in this group has been conducted using mostly proteomes alone, while phylogeography and systematics in the genus have relied on biased information from mitochondrial phylogenies. Here, we generated chromosome-level genome assemblies for three Vipera species and whole-genome sequencing data for 94 samples representing 15 Vipera taxa. This comprehensive dataset has enabled us to disentangle the phylogenomic relationships of this genus, affected by mito-nuclear discordance and pervaded by ancestral introgression. Population-level analyses in the Iberian Peninsula, where the three oldest lineages within Vipera meet, revealed signals of recent adaptive introgression between ecologically dissimilar species, whereas chromosomal rearrangements isolate species occupying similar niches. Finally, using transcriptomic and proteomic data, we characterized the Vipera toxin-encoding genes, in which opposing selective forces were unveiled as common drivers of the evolution of venom as an integrated phenotype.

genomics↗