1. The genetic consequences of population marginality : a case study in maritime pineAdélaïde Theraroz, Santiago C. González-Martínez, Carlos Guadaño-Peyrot, Juliette Archambeau, Sara Pinosio, Francesca Bagnoli, Andrea Piotti, Camilla Avanzi, Giovanni G. Vendramin, Ricardo Alía, Delphine Grivet, Marjana Westergren, 2024, complete scientific database of research data Abstract: This dataset was produced by a consortium of European research Intitutes. For the data collection, needles were sampled from a total of 1,510 individuals from 82 maritime pine populations covering all previously identified gene pools throughout the species range. 10,185 SNPs were genotyped from the multispecies 4TREE SNPs chip (chip produced within the framework of the B4est project). This dataset was used to carry out a population genetics study.
Keywords: population genetics, conservation genetics, marginal populations, Pinus pinaster, genetic indicators
Published in DiRROS: 08.07.2025; Views: 410; Downloads: 329
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2. Marginality indices for biodiversity conservation in forest treesNicolas Picard, Maurizio Marchi, Maria Jesus Serra-Varela, Marjana Westergren, Stephen Cavers, Eduardo Notivol, Andrea Piotti, Paraskevi Alizoti, Michele Bozzano, Santiago C. González-Martínez, 2022, original scientific article Abstract: Marginal and peripheral populations are important for biodiversity conservation. Their original situation in a species’ geographic and ecological space often confers them genetic diversity and traits of high adaptive value. Yet theoretical hypotheses related to marginality are difficult to test because of confounding factors that influence marginality, namely environment, geography, and history. There is an urgent need to develop metrics to disentangle these confounding factors. We designed nine quantitative indices of marginality and peripherality that define where margins lie within species distributions, from a geographical, an environmental and a historical perspective. Using the distribution maps of eight European forest tree species, we assessed whether these indices were idiosyncratic or whether they conveyed redundant information. Using a database on marginal and peripheral populations based on expert knowledge, we assessed the capacity of the indices to predict the marginality status of a population. There was no consistent pattern of correlation between indices across species, confirming that the indices conveyed different information related to the specific geometry of the species distributions. Contrasting with this heterogeneity of correlation patterns across species, the relative importance of the indices to predict the marginality status of populations was consistent across species. However, there was still a significant country effect in the marginality status, showing a variation in expert opinion of marginality vis-á-vis the species distribution. The marginality indices that we developed are entirely based on distribution maps and can be used for any species. They pave the way for testing hypotheses related to marginality and peripherality, with important implications in quantitative ecology, genetics, and biodiversity conservation.
Keywords: centre-periphery hypothesis, environmental indices, geographical indices, migration indices, marginal populations, peripheral populations, in situ genetic conservation
Published in DiRROS: 07.04.2025; Views: 595; Downloads: 351
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3. The genetic consequences of population marginality : a case study in maritime pineAdélaïde Theraroz, Carlos Guadaño-Peyrot, Juliette Archambeau, Sara Pinosio, Francesca Bagnoli, Andrea Piotti, Camilla Avanzi, Giovanni G. Vendramin, Ricardo Alía, Delphine Grivet, Marjana Westergren, Santiago C. González-Martínez, 2024, original scientific article Abstract: Aim: Marginal tree populations, either those located at the edges of the species' rangeor in suboptimal environments, are often a valuable genetic resource for biologicalconservation. However, there is a lack of knowledge about the genetic consequencesof population marginality, estimated across entire species' ranges. Our study ad-dresses this gap by providing information about several genetic indicators and theirvariability in marginal and core populations identified using quantitative marginalityindices.Location: Southwestern Europe and North Africa.Methods: Using 10,185 SNPs across 82 populations of maritime pine (Pinus pinasterAit.), a widespread conifer characterised by a fragmented range, we modelled therelationship of seven genetic indicators potentially related to population evolution-ary resilience, namely genetic diversity (based on both all SNPs and outlier SNPs),inbreeding, genetic differentiation, recessive genetic load and genomic offset, withpopulation geographical, demo-historical and ecological marginality (as estimated bynine quantitative indices). Models were constructed for both regional (introducinggene pool as a random factor) and range-wide spatial scales.Results: We showed a trend towards decreasing overall genetic diversity and increas-ing differentiation with geographic marginality, supporting the centre-periphery hy-pothesis (CPH). However, we found no correlation between population inbreedingand marginality, while geographically marginal populations had a lower recessive ge-netic load (only models without the gene pool effect). Ecologically marginal popula-tions had a higher genomic offset, suggesting higher maladaptation to future climate,albeit some of these populations also had high genetic diversity for climate outliers.Main Conclusions: Overall genetic diversity (but not outlier-based estimates) and dif-ferentiation patterns support the CPH. Ecologically marginal populations and those atthe southern edge could be more vulnerable to climate change due to higher climate maladaptation, as predicted by genomic offsets, and/or lower potentially adaptive ge-netic diversity. This risk is exacerbated by typically small effective population sizesand increasing human impact in marginal populations.
Keywords: population genetics, conservation genetics, marginal populations, Pinus pinaster, genetic indicators
Published in DiRROS: 29.08.2024; Views: 1035; Downloads: 971
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4. Genetic variability of pedunculate oak (Quercus robur L.) at the Mediterranean margin of the distribution rangeMirzeta Memišević Hodžić, Barbara Fussi, Dušan Gömöry, Dalibor Ballian, 2021, review article Abstract: In Bosnia and Herzegovina, pedunculate oak (Quercus robur L.) occurs at the southern margin of its distribution range, close to the glacial refugia of this species. To assess the patterns of genetic diversity distribution at the rear edge of the Holocene colonization, we studied genetic variation in 20 pedunculate oak populations using 14 allozyme loci. Despite considerable differences among populations, neither the numbers of alleles nor genetic diversity showed any geographical trend within the studied area, although small isolated populations showed generally lower allelic richness. The Bayesian analysis of population structure indicated a kind of geographical pattern. We identified no signs of a recent bottleneck. The proximity to multiple glacial refugia explains the outcomes.
Keywords: pedunculate oak, allozyme, genetic variability, marginal populations, rear edge
Published in DiRROS: 22.07.2022; Views: 1516; Downloads: 925
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