| 1. |
- Bertola, Laura D., et al.
(författare)
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A pragmatic approach for integrating molecular tools into biodiversity conservation
- 2024
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Ingår i: Conservation science and practice. - 2578-4854. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Molecular tools are increasingly applied for assessing and monitoring biodiversity and informing conservation action. While recent developments in genetic and genomic methods provide greater sensitivity in analysis and the capacity to address new questions, they are not equally available to all practitioners: There is considerable bias across institutions and countries in access to technologies, funding, and training. Consequently, in many cases, more accessible traditional genetic data (e.g., microsatellites) are still utilized for making conservation decisions. Conservation approaches need to be pragmatic by tackling clearly defined management questions and using the most appropriate methods available, while maximizing the use of limited resources. Here we present some key questions to consider when applying the molecular toolbox for accessible and actionable conservation management. Finally, we highlight a number of important steps to be addressed in a collaborative way, which can facilitate the broad integration of molecular data into conservation. Molecular tools are increasingly applied in conservation management; however, they are not equally available to all practitioners. We here provide key questions when establishing a conservation genetic study and highlight important steps which need to be addressed when these tools are globally applied.image
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| 2. |
- Andersson, Anastasia, 1987-
(författare)
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Hidden biodiversity in an alpine freshwater top predator : Existence, characteristics, and temporal dynamics of cryptic, sympatric brown trout populations
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Intraspecific genetic diversity is imperative to the survival of species in a changing environment, and it plays a vital role in ecosystem function. Since this type of diversity can be difficult to detect it is sometimes referred to as “hidden biodiversity”. When separate and genetically distinct populations of the same species coexist within the same habitat, without apparent barriers to migration and obvious phenotypic divergence, this form of hidden biodiversity is called cryptic sympatry. Knowledge of cryptic sympatry is limited, however, and the aim of this thesis is to increase our understanding of this phenomenon by focusing on a species group where several cases of sympatry have been documented – the salmonids.Using the brown trout (Salmo trutta) as a model, I characterized two previously reported cases of cryptic sympatry occurring in small Swedish alpine lakes with respect to both phenotypic and genetic characteristics. I explored the hypothesis that cryptic sympatry is more common than currently recognized by reviewing literature documenting sympatry, as well as by assessing the statistical power to detect sympatric populations with varying degrees of divergence using commonly applied sample sizes for loci and individuals. Further, I performed a large-scale search for sympatric populations in alpine lakes in central Sweden.I found that cryptic, sympatric populations can coexist while apparently utilizing the same food resources and exhibiting the same adaptive plasticity to their shared environment (Paper I). In one of the empirical cases there were indications that the populations used different creeks for spawning, suggesting that segregation in spawning location contributes to the maintenance of sympatry (Paper II). Further, I found that differences between cryptic, sympatric populations of the same lake may be large with respect to levels of genetic diversity, inbreeding, and connectivity with populations in nearby lakes (Papers II and III). I found support for the hypothesis that cryptic sympatry is more common than generally acknowledged (Papers IV and V). In the literature, cryptic sympatry is rarely reported and typically associated with higher divergence levels than between sympatric populations that differ phenotypically. My results suggest that this to a large extent may be due to limited statistical power when commonly used sample sizes in terms of individuals and loci are applied and the amount of divergence between populations is small (Paper IV). Cryptic sympatry was observed in over 40% of the screened localities (27 lakes), and was shown to be temporally stable over at least 40 years (Paper V).
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| 3. |
- Andersson, Anastasia, 1987-, et al.
(författare)
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Monitoring genetic diversity with new indicators applied to an alpine freshwater top predator
- 2022
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 31:24, s. 6422-6439
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Tidskriftsartikel (refereegranskat)abstract
- Genetic diversity is the basis for population adaptation and long-term survival, yet rarely considered in biodiversity monitoring. One key issue is the need for useful and straightforward indicators of genetic diversity. We monitored genetic diversity over 40 years (1970–2010) in metapopulations of brown trout (Salmo trutta) inhabiting 27 small mountain lakes representing 10 lake systems in central Sweden using >1200 fish per time point. We tested six newly proposed indicators; three were designed for broad, international use in the UN Convention on Biological Diversity (CBD) and are currently applied in several countries. The other three were recently elaborated for national use by a Swedish science-management effort and applied for the first time here. The Swedish indicators use molecular genetic data to monitor genetic diversity within and between populations (indicators ΔH and ΔFST, respectively) and assess the effective population size (Ne-indicator). We identified 29 genetically distinct populations, all retained over time. Twelve of the 27 lakes harboured more than one population indicating that brown trout biodiversity hidden as cryptic, sympatric populations are more common than recognized. The Ne indicator showed values below the threshold (Ne ≤ 500) in 20 populations with five showing Ne < 100. Statistically significant genetic diversity reductions occurred in several populations. Metapopulation structure appears to buffer against diversity loss; applying the indicators to metapopulations suggest mostly acceptable rates of change in all but one system. The CBD indicators agreed with the Swedish ones but provided less detail. All these indicators are appropriate for managers to initiate monitoring of genetic biodiversity.
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| 4. |
- Dussex, Nicolas, et al.
(författare)
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Moose genomes reveal past glacial demography and the origin of modern lineages
- 2020
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Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Numerous megafauna species from northern latitudes went extinct during the Pleistocene/Holocene transition as a result of climate-induced habitat changes. However, several ungulate species managed to successfully track their habitats during this period to eventually flourish and recolonise the holarctic regions. So far, the genomic impacts of these climate fluctuations on ungulates from high latitudes have been little explored. Here, we assemble a de-novo genome for the European moose (Alces alces) and analyse it together with re-sequenced nuclear genomes and ancient and modern mitogenomes from across the moose range in Eurasia and North America.Results: We found that moose demographic history was greatly influenced by glacial cycles, with demographic responses to the Pleistocene/Holocene transition similar to other temperate ungulates. Our results further support that modern moose lineages trace their origin back to populations that inhabited distinct glacial refugia during the Last Glacial Maximum (LGM). Finally, we found that present day moose in Europe and North America show low to moderate inbreeding levels resulting from post-glacial bottlenecks and founder effects, but no evidence for recent inbreeding resulting from human-induced population declines.Conclusions: Taken together, our results highlight the dynamic recent evolutionary history of the moose and provide an important resource for further genomic studies.
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| 5. |
- Dussex, Nicolas, et al.
(författare)
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Range-wide and temporal genomic analyses reveal the consequences of near-extinction in Swedish moose
- 2023
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Ingår i: Communications Biology. - 2399-3642. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Ungulate species have experienced severe declines over the past centuries through overharvesting and habitat loss. Even if many game species have recovered thanks to strict hunting regulation, the genome-wide impacts of overharvesting are still unclear. Here, we examine the temporal and geographical differences in genome-wide diversity in moose (Alces alces) over its whole range in Sweden by sequencing 87 modern and historical genomes. We found limited impact of the 1900s near-extinction event but local variation in inbreeding and load in modern populations, as well as suggestion of a risk of future reduction in genetic diversity and gene flow. Furthermore, we found candidate genes for local adaptation, and rapid temporal allele frequency shifts involving coding genes since the 1980s, possibly due to selective harvesting. Our results highlight that genomic changes potentially impacting fitness can occur over short time scales and underline the need to track both deleterious and selectively advantageous genomic variation.
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| 6. |
- Gilchrist, Ciaran
(författare)
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Hopeful monsters: The role of hybrids in adaptation : The impact of hybridisation and genetic diversity on adaptation to stressful and novel environments
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Adaptation to novel environments can only occur if natural selection has the raw material to act upon. But small, endangered populations are often genetically depleted, and the acquisition of beneficial de novo mutations often takes too long when population face quick and extreme environmental change. An alternative source for new variation is hybridisation and the genomic reshuffling and structural chromosomal changes accompanying it. In this thesis, I use yeast, experimental evolution, and comparative genomics to investigate the impact of different sources of genetic variation in adaptation to stressful environments - standing genetic variation, de novo mutations, and hybridisation.In Chapter I, I investigate the role of aneuploidy in the adaptation of microbial eukaryotes and the genetic mechanisms causing erroneous chromosome segregation, using a meta-analysis. I found that smaller chromosomes are more often aneuploid and that the frequency of segregation errors during cell division is higher in genomes with higher initial ploidy. I also propose that the co-occurrence of hybridisation and aneuploidy may provide an adaptive advantage in stressful environments.Traditionally, microbial experimental evolution studies start with clonal populations, relying on adaptation from de novo mutations alone. In the wild, this is an unlikely scenario. In Chapter II, I evolved genetically diverse founder populations for up to 1000 generations in 4 distinct environments and tracked adaptation dynamics at the phenotypic and genomic level. Almost all populations rapidly increased in fitness but the underlying allele frequency changes were surprisingly diverse and environment-specific. While in some populations all ancestral variation went to fixation in < 30 generations, others maintained genetic diversity across hundreds of generations. I found stunning parallelism of de novo mutations at the gene and pathway level and detected potentially adaptive aneuploidies.Hybridisation drastically boosts the genetic diversity of populations, which can allow for transgressive hybrids (hopeful monsters) with selective advantages in novel environments. In Chapter III, I made hybrid crosses at increasing parental divergence (using divergently evolved populations from Chapter II) and measured how much heterosis and transgressive segregation occurred in F1 and F2 hybrids when exposing them to 50 new, stressful environments. I found that both heterosis and transgression increased as a function of parental divergence, confirming predictions of quantitative genetics theory. Some hybrids were even able to survive in arsenic concentrations lethal for both parents.Anthropogenic climate change drives up rates of hybridisation between natural populations, yet the potential benefits and risks of hybridisation for the long-term conservation of populations are often unknown. In Chapter IV, I compared the survivability of hybrid populations to their parents under deteriorating environmental conditions. I found that hybrids avoided extinction for a significantly longer time than their parents, at all levels of parental divergence. The more divergent the parents the more similar were the responses of replicate crosses, likely due to the erosion of standing genetic variation in the parental populations.In summary, my thesis provides a better understanding of the impact of different sources of genetic diversity in determining a population’s capacity to adapt to environmental change.
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| 7. |
- Hoban, Sean, et al.
(författare)
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Genetic diversity goals and targets have improved, but remain insufficient for clear implementation of the post-2020 global biodiversity framework
- 2023
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Ingår i: Conservation Genetics. - : Springer Science and Business Media LLC. - 1566-0621 .- 1572-9737. ; 24:2, s. 181-191
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Tidskriftsartikel (refereegranskat)abstract
- Genetic diversity among and within populations of all species is necessary for people and nature to survive and thrive in a changing world. Over the past three years, commitments for conserving genetic diversity have become more ambitious and specific under the Convention on Biological Diversity’s (CBD) draft post-2020 global biodiversity framework (GBF). This Perspective article comments on how goals and targets of the GBF have evolved, the improvements that are still needed, lessons learned from this process, and connections between goals and targets and the actions and reporting that will be needed to maintain, protect, manage and monitor genetic diversity. It is possible and necessary that the GBF strives to maintain genetic diversity within and among populations of all species, to restore genetic connectivity, and to develop national genetic conservation strategies, and to report on these using proposed, feasible indicators.
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| 8. |
- Hoban, Sean, et al.
(författare)
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Genetic diversity targets and indicators in the CBD post-2020 Global Biodiversity Framework must be improved
- 2020
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 248
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Tidskriftsartikel (refereegranskat)abstract
- The 196 parties to the Convention on Biological Diversity (CBD) will soon agree to a post-2020 global framework for conserving the three elements of biodiversity (genetic, species, and ecosystem diversity) while ensuring sustainable development and benefit sharing. As the most significant global conservation policy mechanism, the new CBD framework has far-reaching consequences- it will guide conservation actions and reporting for each member country until 2050. In previous CBD strategies, as well as other major conservation policy mechanisms, targets and indicators for genetic diversity (variation at the DNA level within species, which facilitates species adaptation and ecosystem function) were undeveloped and focused on species of agricultural relevance. We assert that, to meet global conservation goals, genetic diversity within all species, not just domesticated species and their wild relatives, must be conserved and monitored using appropriate metrics. Building on suggestions in a recent Letter in Science (Laikre et al., 2020) we expand argumentation for three new, pragmatic genetic indicators and modifications to two current indicators for maintaining genetic diversity and adaptive capacity of all species, and provide guidance on their practical use. The indicators are: 1) the number of populations with effective population size above versus below 500, 2) the proportion of populations maintained within species, 3) the number of species and populations in which genetic diversity is monitored using DNA-based methods. We also present and discuss Goals and Action Targets for post-2020 biodiversity conservation which are connected to these indicators and underlying data. These pragmatic indicators and goals have utility beyond the CBD; they should benefit conservation and monitoring of genetic diversity via national and global policy for decades to come.
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| 9. |
- Hoban, Sean, et al.
(författare)
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Global Commitments to Conserving and Monitoring Genetic Diversity Are Now Necessary and Feasible
- 2021
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Ingår i: BioScience. - : Oxford University Press (OUP). - 0006-3568 .- 1525-3244. ; 71:9, s. 964-976
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Tidskriftsartikel (refereegranskat)abstract
- Global conservation policy and action have largely neglected protecting and monitoring genetic diversity-one of the three main pillars of biodiversity. Genetic diversity (diversity within species) underlies species' adaptation and survival, ecosystem resilience, and societal innovation. The low priority given to genetic diversity has largely been due to knowledge gaps in key areas, including the importance of genetic diversity and the trends in genetic diversity change; the perceived high expense and low availability and the scattered nature of genetic data; and complicated concepts and information that are inaccessible to policymakers. However, numerous recent advances in knowledge, technology, databases, practice, and capacity have now set the stage for better integration of genetic diversity in policy instruments and conservation efforts. We review these developments and explore how they can support improved consideration of genetic diversity in global conservation policy commitments and enable countries to monitor, report on, and take action to maintain or restore genetic diversity.
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| 10. |
- Hoban, Sean, et al.
(författare)
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Monitoring status and trends in genetic diversity for the Convention on Biological Diversity : An ongoing assessment of genetic indicators in nine countries
- 2023
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Ingår i: Conservation Letters. - 1755-263X. ; 16:3
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Tidskriftsartikel (refereegranskat)abstract
- Recent scientific evidence shows that genetic diversity must be maintained, managed, and monitored to protect biodiversity and nature's contributions to people. Three genetic diversity indicators, two of which do not require DNA-based assessment, have been proposed for reporting to the Convention on Biological Diversity and other conservation and policy initiatives. These indicators allow an approximation of the status and trends of genetic diversity to inform policy, using existing demographic and geographic information. Application of these indicators has been initiated and here we describe ongoing efforts in calculating these indicators with examples. We specifically describe a project underway to apply these indicators in nine countries, provide example calculations, address concerns of policy makers and implementation challenges, and describe a roadmap for further development and deployment, incorporating feedback from the broader community. We also present guidance documents and data collection tools for calculating indicators. We demonstrate that Parties can successfully and cost-effectively report these genetic diversity indicators with existing biodiversity observation data, and, in doing so, better conserve the Earth's biodiversity.
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