Biology subjects

Fuselli, S.

Publications and source records attributed to Fuselli, S..

7 recordsLinked to original sources

bioRxiv2025

One Sea, Different Whales: Genomics Sheds Light on a Small Population of Fin Whales

Whales play a crucial role in marine ecosystems, yet many populations face growing environmental pressures. Among them, the fin whale, Balaenoptera physalus, from the Mediterranean Sea remains poorly characterized at the genomic level despite its classification as Endangered and decreasing in population size due to habitat degradation, climate change, and human-induced disturbances. Previous studies based on bioacoustics and telemetry data suggest the presence of resident and migratory subgroups, but the genetic isolation of this population remains uncertain. Here, we sequenced and analysed for the first time whole genomes of the Mediterranean fin whale to provide a comprehensive genomic characterization of this population, assessing its genomic variability, genetic load, population structure and potential for adaptation to environmental stressors. By comparing genomic data from Mediterranean fin whales with populations from the North Atlantic, North Pacific, and the Sea of Cortez (also sequenced in the present study), we aim to determine the degree of genetic isolation and contextualize the Mediterranean population within a broader evolutionary and conservation framework. Our results showed that while Mediterranean fin whales form a distinct genetic cluster, they are not entirely isolated from North Atlantic populations, with gene flow persisting at low levels. Furthermore, we identified a complex substructure within the Mediterranean, supporting the existence of a resident subpopulation. Although this population preserves moderate levels of genomic diversity and adaptive potential, it remains vulnerable to genomic erosion due to continued demographic decline, limited connectivity, and increasing environmental stressors. These findings underscore the urgency of targeted conservation actions and long-term genetic monitoring, especially as climate change accelerates and introduces increasingly unpredictable selective pressures that may exacerbate the risk of genomic erosion and threaten population viability.

genomics↗

bioRxiv2025

Coexisting with humans: genomic and behavioural consequences in a small and isolated bear population

Climate and land use change have increased human-wildlife interactions, potentially reducing wild species density and prompting behavioural adaptations to urbanised environments. It is still debated if behavioural responses are mainly the result of phenotypic plasticity or if they were driven by anthropic selective pressures, especially in small populations. Our study focused on the Apennine brown bear population (Ursus arctos marsicanus), which has coexisted with humans in Central Italy for millennia. We characterised genomic diversity and identified adaptation signals distinctive to this population by comparing whole genome resequencing data across the Holarctic species range. We show that Apennine brown bears possess a unique genomic diversity pattern including selective signatures at genes associated with reduced aggressiveness, possibly involving alternative splicing mechanism. Our findings suggest that even in small and long-isolated populations, selection may shape behavioural traits. We hypothesise that human-induced selection has influenced these changes, reducing conflicts and contributing to the long-term persistence of the Apennine bear and its coexistence with humans.

genomics↗

bioRxiv2023

The unexpected loss of the "hunger hormone" ghrelin in true passerines: A game changer in migration physiology

Migratory birds must accumulate large amounts of fat prior to migration to sustain long flights. In passerines, the small body size limits the amount of energy stores that can be transported and therefore birds undergo cycles of extreme fattening and rapid exhaustion of reserves. Research on these physiological adaptations was rattled by the discovery that birds have lost the main vertebrate regulator of fat deposition, leptin. Recent studies have thus focused on ghrelin, known as the "hunger hormone", a peptide secreted by the gastrointestinal tract to regulate food intake, body mass, and other important functions in vertebrates. Studies on domestic species showed that in birds ghrelin has effects opposite to those described in mammals, such as inhibiting instead of promoting food intake. Furthermore, a series of recent studies have shown that ghrelin administration influences migratory behaviour in passerine birds, suggesting an important role of this hormone in bird migration. However, using comparative genomic analyses we show that ghrelin has been lost in the largest avian taxon Eupasseres, after the basic split from Acanthisitti about 50 million years ago. Eupasserines, also known as True passerines, include all but two of the ca. 10,000 known passerine species. We further found that the ghrelin receptor (growth hormone secretagogue receptor, GHS-R) is still conserved in passerine birds, as indicated by sites under purifying selection and in line with the effects of ghrelin administration. Thus, ghrelin adds to a list of hormones highly conserved in vertebrates that have lost their main functions in specific taxa. The maintenance of a functional receptor system, however, suggests that in eupasserine birds another ligand has replaced ghrelin, perhaps to bypass the feedback system that would hinder large pre-migratory accumulation of subcutaneous fat.

evolutionary biology↗

bioRxiv2023

Unravelling the mystery of endemic versus translocated populations of the endangered Australian lungfish (Neoceratodus forsteri)

The Australian lungfish is a primitive and endangered representative of the subclass Dipnoi. The distribution of this species is limited to south-east Queensland, with some populations considered endemic and others possibly descending from translocations in the late nineteenth century shortly after European discovery. Attempts to resolve the historical distribution for this species have met with conflicting results based on descriptive genetic studies. Understanding if all populations are endemic or some are the result of, or influenced by, translocation events, has implications for conservation management. In this work, we analysed the genetic variation at three types of markers (mtDNA genomes, 11 STRs, and 5,196 nuclear SNPs) using the Approximate Bayesian Computation algorithm to compare several demographic models. We postulated different contributions of Mary River and Burnett River gene pools into the Brisbane River and North Pine River populations, related to documented translocation events. We ran the analysis for each marker separately, and we also estimated the posterior probabilities of the models combining the markers. Nuclear SNPs have the highest power to correctly identify the true model amongst the simulated datasets (where the model was known), but different markers typically provided similar answers. The most supported demographic model able to explain the real dataset implies that an endemic gene pool is present in the Brisbane and North Pine Rivers where past translocations are documented. These results will inform ongoing conservation efforts for this endangered and iconic species and warrant careful consideration of future genetic management of the Australian lungfish populations.

evolutionary biology↗

bioRxiv2021

Selection-driven adaptation to the extreme Antarctic environment in the Emperor penguin

The eco-evolutionary history of penguins is profoundly influenced by their shift from temperate to cold environments. Breeding only in Antarctica during the winter, the Emperor penguin appears as an extreme outcome of this process, with unique features related to insulation, heat production and energy management. However, whether this species actually diverged from a less cold-adapted ancestor, thus more similar in ecology to its sister species, the King penguin, is still an open question. As the Antarctic niche shift likely resulted in vast changes in selective pressure experienced by the Emperor penguin, the identification and relative quantification of the genomic signatures of selection, unique to each of these sister species, could answer this question. Applying a suite of phylogeny-based methods on 7,651 orthologous gene alignments of seven penguins and 13 other birds, we identified a set of candidate genes showing significantly different selection regimes either in the Emperor or in the King penguin lineage. Our comparative approach unveils a more pervasive selection shift in the Emperor penguin, supporting the hypothesis that its extreme cold adaptation is a derived state from a more King penguin-like ecology. Among the candidate genes under selection in the Emperor penguin, four genes (TRPM8, LEPR, CRB1, and SFI1) were identified before in other cold adapted vertebrates, while, on the other hand, 161 genes can be assigned to functional pathways relevant to cold adaptation (e.g., cardiovascular system, lipid, fatty acid and glucose metabolism, insulation, etc.). Our results show that extreme cold adaptation in the Emperor penguin largely involved unique genetic options which, however, affect metabolic and physiological traits common to other cold-adapted homeotherms.

evolutionary biology↗

bioRxiv2021

From STRs to SNPs via ddRAD-seq: geographic assignment of confiscated tortoises at reduced costs

Assigning individuals to their source populations is crucial for conservation research, especially for endangered species threatened by illegal trade and translocations. Genetic assignment can be achieved with different types of molecular markers, but technical advantages and cost saving are recently promoting the shift from short tandem repeats (STRs) to single nucleotide polymorphisms (SNPs). Here, we designed, developed, and tested a small panel of SNPs for cost-effective geographic assignment of individuals with unknown origin of the endangered Mediterranean tortoise Testudo hermanni. We started by performing a ddRAD-seq experiment on 70 wild individuals of T. hermanni from 38 locations. Results obtained using 3,182 SNPs are comparable to those previously obtained using STR markers in terms of genetic structure and power to identify the macro-area of origin. However, our SNPs revealed further insights into the substructure in Western populations, especially in Southern Italy. A small panel of highly informative SNPs was then selected and tested by genotyping 190 individuals using the KASP genotyping chemistry. All the samples from wild populations of known geographic origin were genetically re-assigned with high accuracy to the original population. This reduced SNPs panel represents an efficient molecular tool that enables individuals to be genotyped at low cost (less than {euro}15 per sample) for geographical assignment and identification of hybrids. This information is crucial for the management in-situ of confiscated animals and their possible re-allocation in the wild. Our methodological pipeline can easily be extended to other species.

genomics↗

bioRxiv2020

The genetic structure and adaptation of Andean highlanders and Amazonian dwellers is influenced by the interplay between geography and culture

Western South America was one of the worldwide cradles of civilization. The well known Inca Empire was the tip of the iceberg of a cultural and biological evolutionary process that started 14-11 thousand years ago. Genetic data from 18 Peruvian populations reveal that: (1) The between-population homogenization of the central-southern Andes and its differentiation with respect to Amazonian populations of similar latitudes do not extend northward. Instead, longitudinal gene flow between the northern coast of Peru, Andes and Amazonia accompanied cultural and socioeconomic interactions revealed by archeological studies. This pattern recapitulates the environmental and cultural differentiation between the fertile north, where altitudes are lower; and the arid south, where the Andes are higher, acting as a genetic barrier between the sharply different environments of the Andes and Amazonia (2). The genetic homogenization between the populations of the arid Andes is not only due to migration during the Inca Empire or the subsequent colonial period. It started at least during the earlier expansion of the pre-Inca Wari Empire (600-1000 YBP) (3) This demographic history allowed for cases of positive natural selection in the high and arid Andes vs. the low Amazon tropical forest: in the Andes, HAND2-AS1 (heart and neural crest derivatives expressed 2 antisense RNA1, related with cardiovascular function) and DUOX2 (dual oxidase 2, related to thyroid function and innate immunity) genes; in the Amazon, the gene encoding for the CD45 protein, essential for antigen recognition by T/B lymphocytes in viral-host interaction, consistent with the host-virus arms race hypothesis.

evolutionary biology↗