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Sarre SD, Adamack AT, Hitchen Y, Soulsbury CD, Gruber B, Berry OF. The genetic signature left by the range expansion of red foxes in Australia is detectable after more than 80 years of population stability. Ecol Evol 2024; 14:e11212. [PMID: 38584770 PMCID: PMC10994981 DOI: 10.1002/ece3.11212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/12/2024] [Accepted: 03/18/2024] [Indexed: 04/09/2024] Open
Abstract
Reconstructing biological invasions from historical sources can provide insights into how they occur but are difficult to do when invasions are poorly documented. Genetic signatures left by invaders can also offer insights into invasion routes, points of origin and general biology but often present conclusions that are contradictory to expectations. Here, we test the ability of continental-wide microsatellite genotype data from 29 loci and 3122 samples to reconstruct the well-documented invasion of red foxes Vulpes vulpes from the United Kingdom into Australia over 150 years ago, an invasion that has led to the extinction of many native species. Our analysis reveals several key signals of invasion evident in Australian foxes. They display lower levels of diversity than foxes sampled from the UK, exhibit clines in diversity from the point of introduction (south-east Australia) to the edge of their range, and show strong evidence of allele surfing in westerly and north-easterly directions. These characteristics are consistent with a single point of origin followed by rapid expansion in westerly and north-easterly directions as suggested by historical records. We also find little genetic structure in foxes across Australia with only the vast Nullarbor Plains and Great Victoria Desert region presenting a detectable barrier to their dispersal. As such, no mainland region within the current range of foxes can be considered genetically isolated and therefore appropriate for localised eradication efforts. Overall, our analyses demonstrate the ability of comprehensive population genetic studies to reconstruct invasion histories even after more than 80 years since colonisation was stabilised.
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Affiliation(s)
- Stephen D. Sarre
- Centre for Conservation Ecology and Genomics, Institute for Applied EcologyUniversity of CanberraCanberraAustralian Capital TerritoryAustralia
| | - Aaron T. Adamack
- Centre for Conservation Ecology and Genomics, Institute for Applied EcologyUniversity of CanberraCanberraAustralian Capital TerritoryAustralia
- Science Branch, Northwest Atlantic Fisheries CentreFisheries and Oceans CanadaSt. John'sNewfoundland and LabradorCanada
| | - Yvette Hitchen
- School of Biological SciencesThe University of Western AustraliaCrawleyWestern AustraliaAustralia
- Helix Molecular SolutionsLeedervilleWestern AustraliaAustralia
| | - Carl D. Soulsbury
- School of Life & Environmental SciencesUniversity of LincolnLincolnUK
| | - Bernd Gruber
- School of Biological SciencesThe University of Western AustraliaCrawleyWestern AustraliaAustralia
| | - Oliver F. Berry
- School of Biological SciencesThe University of Western AustraliaCrawleyWestern AustraliaAustralia
- National Collections and Marine Infrastructure, CSIRO, Indian Ocean Marine Research CentreThe University of Western AustraliaCrawleyWestern AustraliaAustralia
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Vieu JC, Koubínová D, Grant JR. Population Genetic Structure and Diversity of Cryptic Species of the Plant Genus Macrocarpaea (Gentianaceae) from the Tropical Andes. PLANTS (BASEL, SWITZERLAND) 2023; 12:1710. [PMID: 37111932 PMCID: PMC10145315 DOI: 10.3390/plants12081710] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/29/2023] [Accepted: 04/14/2023] [Indexed: 06/19/2023]
Abstract
The Pleistocene climatic oscillations (PCO) that provoked several cycles of glacial-interglacial periods are thought to have profoundly affected species distribution, richness and diversity around the world. While the effect of the PCO on population dynamics at temperate latitudes is well known, considerable questions remain about its impact on the biodiversity of neotropical mountains. Here, we use amplified fragment length polymorphism molecular markers (AFLPs) to investigate the phylogeography and genetic structure of 13 plant species belonging to the gentian genus Macrocarpaea (Gentianaceae) in the tropical Andes. These woody herbs, shrubs or small trees show complex and potentially reticulated relationships, including cryptic species. We show that populations of M. xerantifulva in the dry system of the Rio Marañón in northern Peru have lower levels of genetic diversity compared to other sampled species. We suggest that this is due to a recent demographic bottleneck resulting from the contraction of the montane wet forests into refugia because of the expansion of the dry system into the valley during the glacial cycles of the PCO. This may imply that the ecosystems of different valleys of the Andes might have responded differently to the PCO.
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3
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Genetic Variability and Admixture Zones in the Italian Populations of Turkey Oak ( Quercus cerris L.). LIFE (BASEL, SWITZERLAND) 2022; 13:life13010018. [PMID: 36675965 PMCID: PMC9863001 DOI: 10.3390/life13010018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 12/02/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022]
Abstract
The Turkey oak (Quercus cerris L.) is widely distributed in Italy, where it is the ecologically dominant oak on sandy and acidic soil. In this work, we analysed 23 natural populations by means of eight SSR (microsatellite) markers, to obtain the first synthetic map of genetic variability for this species and to study its dispersion during the Holocene, due to the possibility that at least one refugium during the Last Glacial Maximum was in Italy. The analyses showed a good amount of genetic variability together with fair differentiation between populations, as indicated by FST = 0.059. A Bayesian analysis of the amount of admixture among populations revealed the presence of four putative gene pools of origin and a rough subdivision of the populations according to their geographic location, as confirmed by the spatial analysis. No evidence for the existence of putative refugial populations was found; however, this study paves the way for the planning of conservation strategies also with regard to the relationship between Turkey oak and other oak species in Italy.
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4
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Ochoa-Zavala M, Diaz-Jaimes P, Ortega-García S, Galván-Magaña F. Genetic divergence at species boundaries of the dolphinfish ( Coryphaena hippurus) in the Tropical Eastern Pacific. PeerJ 2022; 10:e14389. [PMID: 36415864 PMCID: PMC9676019 DOI: 10.7717/peerj.14389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 10/23/2022] [Indexed: 11/18/2022] Open
Abstract
Background Marine species constitute commercially important resources, and knowledge about mechanisms that shape phylogeographic patterns and genetic structure provides valuable information for conservation. The dolphinfish, Coryphaena hippurus, is one of the most important species caught in the Tropical Eastern Pacific (TEP). However, the lack of consensus about the existence of genetically differentiated populations in the area has hindered the adoption of management strategies to ensure its viability. Methods We assessed genetic variation and phylogeographic structure using two mitochondrial genes and 14 nuclear DNA microsatellite loci. Population genetic tools were used to characterize the spatial distribution of genetic variation of C. hippurus in the TEP, evaluate the extent of connectivity between dolphinfish populations, infer potential barriers to gene flow, and test for signals of contemporary and historical demographic expansions. Results Mitochondrial DNA sequences showed genetic homogeneity across locations in the TEP, as well as a strong signal of population expansion dated to the late Pleistocene. In contrast, nuclear microsatellite markers resolved four genetically distinct groups with a remarked genetic differentiation between the most distant locations, at the northern and southern boundaries of the species' range. High mean genetic diversity was found at all localities (Hs = 0.66-0.81). Notwithstanding, positive F IS and low effective population size (Ne = 77.9-496.4) were also recorded. Conclusions The distribution of genetic variation could be related to expansion-contraction cycles following seasonal temperature changes at transitional areas, promoting population subdivisions. However, we cannot rule out the effect of oceanographic dynamics to the observed patterns. Although this marine species remains highly abundant despite commercial exploitation, the low Ne values are of conservation concern and must be considered in fishery management plans.
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Affiliation(s)
- Maried Ochoa-Zavala
- Unidad de Ecología y Biodiversidad Acuática, Instituto de Ciencias del Mar y Limnnología, Universidad Nacional Autónoma de México, CDMX, Mexico,Escuela Nacional de Estudios Superiores, Unidad Morelia, Universidad Nacional Autónoma de México, Morelia, Michoacán, Mexico
| | - Pindaro Diaz-Jaimes
- Unidad de Ecología y Biodiversidad Acuática, Instituto de Ciencias del Mar y Limnnología, Universidad Nacional Autónoma de México, CDMX, Mexico
| | - Sofía Ortega-García
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, México
| | - Felipe Galván-Magaña
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, México
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5
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Chiocchio A, Zampiglia M, Biaggini M, Biello R, Di Tizio L, Leonetti FL, Olivieri O, Sperone E, Trabalza-Marinucci M, Corti C, Canestrelli D. Unveiling a hotspot of genetic diversity in southern Italy for the endangered Hermann’s tortoise Testudo hermanni. BMC Ecol Evol 2022; 22:131. [DOI: 10.1186/s12862-022-02075-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 09/28/2022] [Indexed: 11/09/2022] Open
Abstract
Abstract
Background
Hotspots of intraspecific genetic diversity represent invaluable resources for species to cope with environmental changes, and their identification is increasingly recognized as a major goal of conservation ecology research. However, even for iconic and endangered species, conservation strategies are often planned without thorough information on the geographic patterns of genetic variation. Here, we investigated the spatial patterns of genetic variation of the endangered Hermann’s tortoise Testudo hermanni in the Italian Peninsula by genotyping 174 individuals at 7 microsatellite loci, with the aim to contribute to planning effective conservation strategies.
Results
Ordination-based and Bayesian clustering analyses consistently identified three main genetic clusters, one spread in the central and northern part of the peninsula, and two restricted to southern Italy and Sicily, respectively. The highest levels of genetic diversity were found in populations of the southern cluster and, in particular, at the northern edges of its distribution (He > 0.6, Ar > 2.8 ), that correspond to areas of putative secondary contact and admixture between distinct lineages. Our results clearly identify a hotspot of genetic diversity for the Hermann’s tortoise in southern Italy.
Conclusion
We inferred the evolutionary history and the spatial patterns of genetic variation of the Hermann’s tortoise in the Italian Peninsula. We identified three main genetic clusters along the peninsula and a hotspot of intraspecific diversity in southern Italy. Our results underline the urgent need for conservation actions to warrant the long-term persistence of viable tortoise populations in this area. Furthrmore, these data add further evidence to the role of southern Italy as a biodiversity hotspot for temperate fauna, claiming for higher consideration of this area in large scale conservation programs.
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Srinivas Y, Yumnam B, Dutta S, Jhala Y. Assessing genetic diversity and population structure for prioritizing conservation of the critically endangered Great Indian Bustard (Aredotis nigriceps). Glob Ecol Conserv 2022. [DOI: 10.1016/j.gecco.2022.e02332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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7
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Contrasting genetic trajectories of endangered and expanding red fox populations in the western U.S. Heredity (Edinb) 2022; 129:123-136. [PMID: 35314789 PMCID: PMC9338314 DOI: 10.1038/s41437-022-00522-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/24/2022] [Accepted: 02/25/2022] [Indexed: 12/04/2022] Open
Abstract
As anthropogenic disturbances continue to drive habitat loss and range contractions, the maintenance of evolutionary processes will increasingly require targeting measures to the population level, even for common and widespread species. Doing so requires detailed knowledge of population genetic structure, both to identify populations of conservation need and value, as well as to evaluate suitability of potential donor populations. We conducted a range-wide analysis of the genetic structure of red foxes in the contiguous western U.S., including a federally endangered distinct population segment of the Sierra Nevada subspecies, with the objectives of contextualizing field observations of relative scarcity in the Pacific mountains and increasing abundance in the cold desert basins of the Intermountain West. Using 31 autosomal microsatellites, along with mitochondrial and Y-chromosome markers, we found that populations of the Pacific mountains were isolated from one another and genetically depauperate (e.g., estimated Ne range = 3–9). In contrast, red foxes in the Intermountain regions showed relatively high connectivity and genetic diversity. Although most Intermountain red foxes carried indigenous western matrilines (78%) and patrilines (85%), the presence of nonindigenous haplotypes at lower elevations indicated admixture with fur-farm foxes and possibly expanding midcontinent populations as well. Our findings suggest that some Pacific mountain populations could likely benefit from increased connectivity (i.e., genetic rescue) but that nonnative admixture makes expanding populations in the Intermountain basins a non-ideal source. However, our results also suggest contact between Pacific mountain and Intermountain basin populations is likely to increase regardless, warranting consideration of risks and benefits of proactive measures to mitigate against unwanted effects of Intermountain gene flow.
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8
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Campbell EO, MacDonald ZG, Gage EV, Gage RV, Sperling FAH. Genomics and ecological modelling clarify species integrity in a confusing group of butterflies. Mol Ecol 2022; 31:2400-2417. [PMID: 35212068 DOI: 10.1111/mec.16407] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 02/11/2022] [Accepted: 02/15/2022] [Indexed: 11/30/2022]
Abstract
Recent advances in both genomics and ecological modelling present new, multidisciplinary opportunities for resolving species boundaries and understanding the mechanisms that maintain their integrity in regions of contact. Here, we use a combination of high-throughput DNA sequencing and ecological niche modelling to resolve species boundaries and niche divergence within the Speyeria atlantis-hesperis (Lepidoptera: Nymphalidae) complex, a confusing group of North American butterflies. This complex is notorious for its muddled species delimitations, morphological ambiguity, and extensive mito-nuclear discordance. Our admixture and multispecies coalescent-based analyses of single nucleotide polymorphisms identified substantial divergences between S. atlantis and S. hesperis in areas of contact, as well as between distinct northern and southern lineages within S. hesperis. Our results also provide evidence of past introgression relating to another species, S. zerene, which previous work has shown to be more distantly related to the S. atlantis-hesperis complex. We then used ecological models to predict habitat suitability for each of the three recovered genomic lineages in the S. atlantis-hesperis complex and assess their pairwise niche divergence. These analyses resolved that these three lineages are significantly diverged in their respective niches and are not separated by discontinuities in suitable habitat that might present barriers to gene flow. We therefore infer that ecologically-mediated selection resulting in disparate habitat associations is a principal mechanism reinforcing their genomic integrity. Overall, our results unambiguously support significant evolutionary and ecological divergence between the northern and southern lineages of S. hesperis, sufficient to recognize the southern evolutionary lineage as a distinct species, called S. nausicaa based on taxonomic priority.
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Affiliation(s)
- E O Campbell
- Department of Biological Sciences, Biosciences Centre, University of Alberta, Edmonton, AB, Canada
| | - Z G MacDonald
- Department of Biological Sciences, Biosciences Centre, University of Alberta, Edmonton, AB, Canada.,Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
| | - E V Gage
- Texas Museum of Entomology, Pipe Creek, TX, U.S.A
| | | | - F A H Sperling
- Department of Biological Sciences, Biosciences Centre, University of Alberta, Edmonton, AB, Canada
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9
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Snetsinger M, Row JR, Hazell ME, Plain D, Lougheed SC. Comparing the population structure of the specialist Butler’s Gartersnake (Thamnophis butleri) and the generalist Eastern Gartersnake (Thamnophis sirtalis sirtalis) in Ontario (Canada) and Michigan (USA). CAN J ZOOL 2022. [DOI: 10.1139/cjz-2020-0205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Species differing in life-history attributes vary in their responses to features within a shared landscape. We evaluated genetic structure of sympatric gartersnake species in southwestern Ontario (Canada) and southeastern Michigan (USA), where habitat fragmentation is high due to agriculture and urbanization. We surveyed genetic structure of a habitat specialist, Butler’s Gartersnake (Thamnophis butleri (Cope, 1889)), and a habitat generalist, Eastern Gartersnake (Thamnophis sirtalis sirtalis (Linnaeus, 1758)), using DNA microsatellites. Bayesian clustering, discriminant analysis of principal components, and pairwise population comparisons revealed genetic differentiation among three major regional clusters of Butler’s Gartersnake with evidence of further division within one. Genetic clustering of Butler’s Gartersnake suggest that inhospitable habitat limits dispersal. Eastern Gartersnakes showed less structure, with assignment tests implying a single genetic cluster. We found positive significant Mantel’s r for both species in the smallest distance class (<15 km), but significant isolation by distance for Butler’s Gartersnake only. These findings together imply that connectivity for Eastern Gartersnakes is less impacted by habitat loss and fragmentation or that we were less able to detect their effects. Our study shows the value of multispecies comparisons in studies seeking to understand the underlying causes of genetic structure in natural populations.
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Affiliation(s)
- Megan Snetsinger
- Department of Biology, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - Jeffrey R. Row
- Minnow Environmental Inc., 2 Lamb Street, Georgetown, ON L7G 3M9, Canada
| | - Megan E. Hazell
- Department of Biology, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - Dennis Plain
- Aamjiwnaang First Nation, Band Office, 978 Tashmoo Avenue, Sarnia, ON N7T 7H5, Canada
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De R, Sharma R, Davidar P, Arumugam N, Sedhupathy A, Puyravaud JP, Selvan KM, Rahim PA, Udayraj S, Parida J, Digal DK, Kanagaraj R, Kakati K, Nigam P, Williams AC, Habib B, Goyal SP. Pan-India population genetics signifies the importance of habitat connectivity for wild Asian elephant conservation. Glob Ecol Conserv 2021. [DOI: 10.1016/j.gecco.2021.e01888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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11
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Silva-Arias GA, Caballero-Villalobos L, Giudicelli GC, Freitas LB. Landscape and climatic features drive genetic differentiation processes in a South American coastal plant. BMC Ecol Evol 2021; 21:196. [PMID: 34702161 PMCID: PMC8547116 DOI: 10.1186/s12862-021-01916-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 09/22/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Historical and ecological processes shape patterns of genetic diversity in plant species. Colonization to new environments and geographical landscape features determine, amongst other factors, genetic diversity within- and differentiation between-populations. We analyse the genetic diversity and population structure of Calibrachoa heterophylla to infer the influence of abiotic landscape features on the level of gene flow in this coastal species of the South Atlantic Coastal Plain. RESULTS The C. heterophylla populations located on early-deposited coastal plain regions show higher genetic diversity than those closer to the sea. The genetic differentiation follows a pattern of isolation-by-distance. Landscape features, such as water bodies and wind corridors, and geographical distances equally explain the observed genetic differentiation, whereas the precipitation seasonality exhibits a strong signal for isolation-by-environment in marginal populations. The estimated levels of gene flow suggest that marginal populations had restricted immigration rates enhancing differentiation. CONCLUSIONS Topographical features related to coastal plain deposition history influence population differentiation in C. heterophylla. Gene flow is mainly restricted to nearby populations and facilitated by wind fields, albeit without any apparent influence of large water bodies. Furthermore, differential rainfall regimes in marginal populations seem to promote genetic differentiation.
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Affiliation(s)
- Gustavo A Silva-Arias
- Professorship for Population Genetics, Department of Life Science Systems, Technical University of Munich, Freising, Germany. .,Laboratory of Molecular Evolution, Department of Genetics, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
| | - Lina Caballero-Villalobos
- Laboratory of Molecular Evolution, Department of Genetics, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Giovanna C Giudicelli
- Laboratory of Molecular Evolution, Department of Genetics, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Loreta B Freitas
- Laboratory of Molecular Evolution, Department of Genetics, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
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de Souza TE, Cruz GADS, de Moura RDC. Impact of Limited Dispersion Capacity and Natural Barriers on the Population Structure of the Grasshopper Ommexecha virens (Orthoptera: Ommexechidae). NEOTROPICAL ENTOMOLOGY 2021; 50:706-715. [PMID: 33978918 DOI: 10.1007/s13744-021-00878-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 04/21/2021] [Indexed: 06/12/2023]
Abstract
The grasshopper Ommexecha virens Serville has low dispersion capacity, and it is regarded as a specialist, only being found in sandy, dry environments with high incidence of sunlight. Considering these aspects, we evaluated the diversity and genetic structure of O. virens natural populations using ISSR (Inter Simple Sequence Repeat) markers. The data pointed to low expected heterozygosity for some populations (HE = 0.06-0.09), probably a consequence of positive inbreeding, which is typical of species showing low or null dispersion indices. Moreover, significant genetic differentiation was observed (FST = 0.50 and GST = 0.51), as well as low number of migrants (Nm = 0.47), indicating that the populations are genetically differentiated. This is likely related to the limitation in dispersing and fragmentation of suitable environment localities colonized by O. virens. The populations of O. virens were structured in three genetic groups associated to different landscapes, revealing the presence of a secondary contact zone, possibly arisen from isolation followed by genetic divergence among populations and subsequent gene flow of divergent individuals of O. virens. At last, we found positive isolation by distance (IBD; r: 0.427; P: 0.025) which is an important factor, since it may be adding to the emergence of reproductive barriers among individuals of O. virens that have been experiencing isolation.
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Affiliation(s)
- Tyago Eufrásio de Souza
- Laboratório de Biodiversidade e Genética de Insetos, Universidade de Pernambuco (UPE), Recife, Pernambuco, Brazil
| | - Geyner Alves Dos Santos Cruz
- Laboratório de Biodiversidade e Genética de Insetos, Universidade de Pernambuco (UPE), Recife, Pernambuco, Brazil.
- Laboratório de Biodiversidade e Genética Evolutiva, Universidade de Pernambuco (UPE), Petrolina, Pernambuco, Brazil.
| | - Rita de Cássia de Moura
- Laboratório de Biodiversidade e Genética de Insetos, Universidade de Pernambuco (UPE), Recife, Pernambuco, Brazil.
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E Luzuriaga-Aveiga V, Ugarte M, Weir JT. Distinguishing genomic homogenization from parapatric speciation in an elevationally replacing pair of Ramphocelus tanagers. Mol Ecol 2021; 30:5517-5529. [PMID: 34403554 DOI: 10.1111/mec.16128] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 07/30/2021] [Accepted: 08/11/2021] [Indexed: 12/14/2022]
Abstract
Geographically connected species pairs with weakly differentiated genomes could either represent cases of genomic homogenization in progress or of incipient parapatric speciation. Discriminating between these processes is difficult because intermediate stages of either may produce weakly differentiated genomes that diverge at few locations. We used coalescent modelling applied to a genome-wide sample of SNPs to discriminate between speciation with gene flow and genomic homogenization in two phenotypically distinct but genomically weakly diverged species of elevationally replacing Ramphocelus tanagers, forming a hybrid zone in the Andean foothills. We found overwhelming support for a model of genomic homogenization following secondary contact. Simulating under this model suggested that our species pair was differentiated (FST = 0.30) at secondary contact but that most of the genome has rapidly homogenized during 254 Ky of high gene flow towards the present (FST = 0.02). Despite extensive genome-wide homogenization, plumage remains distinctive with a narrower than expected geographic cline width, indicating divergent selection on colour. We found two SNPs significantly associated with plumage colour, which retain moderately high FST . We conclude that the majority of the genome has fused, but that divergent selection on select loci probably maintains the geographically structured colour differences between these incipient species.
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Affiliation(s)
- Vanessa E Luzuriaga-Aveiga
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.,Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Mauricio Ugarte
- Área de Ornitología, Universidad Nacional de San Agustín de Arequipa, Museo de Historia Natural Arequipa, Peru
| | - Jason T Weir
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.,Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada.,Department of Ornithology, Royal Ontario Museum, Toronto, Ontario, Canada
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14
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Chabot AA, Lougheed SC. Integrative assessment of intraspecific diversification in Loggerhead Shrike ( Lanius ludovicianus) provides insight on the geographic pattern of phenotypic divergence and process of speciation. CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Integrated studies of the geographical, ecological, and historical factors that shape intraspecific phenotypic and genetic variation can help us to decipher the processes leading to geographic patterns of population divergence and speciation. We quantify and compare morphological and genetic variation in the Loggerhead Shrike (Lanius ludovicianus Linnaeus, 1766), a broadly distributed passerine in North America with both migratory and non-migratory populations that occupy a diversity of habitats and topographies. The geographic distributions and patterns of differentiation among subspecies suggest that migration has strongly impacted population divergence, including the habit of migrating itself, but also dispersal. Patterns of mitochondrial and nuclear genetic differentiation can be attributed to female-biased dispersal and to increased dispersal rates and distances in migratory populations. Weak phenotypic differentiation among migratory versus migratory and non-migratory populations suggest that migration may more strongly affect morphology than adaptation to local habitats. Our results generally support previous subspecific designations with two notable exceptions. We found little genetic differentiation between two subspecies (Lanius ludovicianus gambeli Ridgway, 1887 and Lanius ludovicianus mexicanus C.L. Brehm, 1854), but identify a new, distinct subspecies, which we refer to as Lanius ludovicianus centralis ssp. nov.
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Affiliation(s)
- Amy A. Chabot
- Department of Biology, Queen’s University, Kingston, ON K7L 3N6, Canada
- African Lion Safari, Cambridge, ON N1R 5S2, Canada
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15
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Carress H, Lawson DJ, Elhaik E. Population genetic considerations for using biobanks as international resources in the pandemic era and beyond. BMC Genomics 2021; 22:351. [PMID: 34001009 PMCID: PMC8127217 DOI: 10.1186/s12864-021-07618-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 04/14/2021] [Indexed: 12/11/2022] Open
Abstract
The past years have seen the rise of genomic biobanks and mega-scale meta-analysis of genomic data, which promises to reveal the genetic underpinnings of health and disease. However, the over-representation of Europeans in genomic studies not only limits the global understanding of disease risk but also inhibits viable research into the genomic differences between carriers and patients. Whilst the community has agreed that more diverse samples are required, it is not enough to blindly increase diversity; the diversity must be quantified, compared and annotated to lead to insight. Genetic annotations from separate biobanks need to be comparable and computable and to operate without access to raw data due to privacy concerns. Comparability is key both for regular research and to allow international comparison in response to pandemics. Here, we evaluate the appropriateness of the most common genomic tools used to depict population structure in a standardized and comparable manner. The end goal is to reduce the effects of confounding and learn from genuine variation in genetic effects on phenotypes across populations, which will improve the value of biobanks (locally and internationally), increase the accuracy of association analyses and inform developmental efforts.
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Affiliation(s)
- Hannah Carress
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Daniel John Lawson
- School of Mathematics and Integrative Epidemiology Unit, University of Bristol, Bristol, UK
| | - Eran Elhaik
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK. .,Department of Biology, Lund University, Lund, Sweden.
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16
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Binks RM, Steane DA, Byrne M. Genomic divergence in sympatry indicates strong reproductive barriers and cryptic species within Eucalyptus salubris. Ecol Evol 2021; 11:5096-5110. [PMID: 34025994 PMCID: PMC8131811 DOI: 10.1002/ece3.7403] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/05/2021] [Accepted: 02/09/2021] [Indexed: 12/26/2022] Open
Abstract
Genetic studies are increasingly detecting cryptic taxa that likely represent a significant component of global biodiversity. However, cryptic taxa are often criticized because they are typically detected serendipitously and may not receive the follow-up study required to verify their geographic or evolutionary limits. Here, we follow-up a study of Eucalyptus salubris that unexpectedly detected two divergent lineages but was not sampled sufficiently to make clear interpretations. We undertook comprehensive sampling for an independent genomic analysis (3,605 SNPs) to investigate whether the two purported lineages remain discrete genetic entities or if they intergrade throughout the species' range. We also assessed morphological and ecological traits, and sequenced chloroplast DNA. SNP results showed strong genome-wide divergence (F ST = 0.252) between two discrete lineages: one dominated the north and one the southern regions of the species' range. Within lineages, gene flow was high, with low differentiation (mean F ST = 0.056) spanning hundreds of kilometers. In the central region, the lineages were interspersed but maintained their genomic distinctiveness: an indirect demonstration of reproductive isolation. Populations of the southern lineage exhibited significantly lower specific leaf area and occurred on soils with lower phosphorus relative to the northern lineage. Finally, two major chloroplast haplotypes were associated with each lineage but were shared between lineages in the central distribution. Together, these results suggest that these lineages have non-contemporary origins and that ecotypic adaptive processes strengthened their divergence more recently. We conclude that these lineages warrant taxonomic recognition as separate species and provide fascinating insight into eucalypt speciation.
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Affiliation(s)
- Rachel M. Binks
- Biodiversity and Conservation ScienceDepartment of Biodiversity, Conservation and AttractionsBentley Delivery CentreBentleyWAAustralia
| | - Dorothy A. Steane
- School of Natural Sciences and ARC Training Centre for Forest ValueUniversity of TasmaniaHobartTasmaniaAustralia
- CSIRO Land and WaterSandy BayTasmaniaAustralia
| | - Margaret Byrne
- Biodiversity and Conservation ScienceDepartment of Biodiversity, Conservation and AttractionsBentley Delivery CentreBentleyWAAustralia
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17
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Boukteb A, Sakaguchi S, Ichihashi Y, Kharrat M, Nagano AJ, Shirasu K, Bouhadida M. Analysis of Genetic Diversity and Population Structure of Orobanche foetida Populations From Tunisia Using RADseq. FRONTIERS IN PLANT SCIENCE 2021; 12:618245. [PMID: 33927733 PMCID: PMC8078179 DOI: 10.3389/fpls.2021.618245] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 02/10/2021] [Indexed: 05/25/2023]
Abstract
Orobanche foetida Poiret is a holoparasitic plant that lacks chlorophyll and totally depending on its host for its growth. Orobanche foetida parasitizes host plant roots and extract nutrient and water via a haustorium. Although O. foetida distributes in the Mediterranean region as a wild plant parasite, it parasitizes faba bean causing serious damages which may reach 90% yield losses in Tunisia. Analysis of genetic diversity of the parasite is important to better understand its evolution and spread, remained largely unknown. In this work, we present the first study on genetic diversity and population structure using the robust technique Restriction-site-Associated DNA sequencing (RADseq) for Orobanche spp. We collected 244 samples of O. foetida from 18 faba bean fields in the north of Tunisia including 17 populations from the north-west and one population form the north-east. To overcome the difficulty of SNP discovery in O. foetida genome as a non-model and tetraploid plant, we utilized three different informatics pipelines, namely UNEAK, pyRAD and Stacks. This study showed that genetic differentiation occurred in the Tunisian O. foetida emphasizing the isolation by distance effect. However, no strong population clustering was detected in this work basing on the three data sets and clustering methods used. The present study shed the light on the current distribution and the genetic variation situation of the fetid broomrape in Tunisia, highlighting the importance of understanding the evolution of this parasite and its genetic background. This will aid in developing efficient strategies to control this parasite and its expansion in Tunisia and worldwide.
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Affiliation(s)
- Amal Boukteb
- Faculty of Science of Tunis, University of Tunis El Manar, Tunis, Tunisia
- Field Crop Laboratory, National Institute of Agricultural Research of Tunisia, Carthage University, Tunis, Tunisia
| | - Shota Sakaguchi
- Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
| | | | - Mohamed Kharrat
- Field Crop Laboratory, National Institute of Agricultural Research of Tunisia, Carthage University, Tunis, Tunisia
| | | | - Ken Shirasu
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Mariem Bouhadida
- Field Crop Laboratory, National Institute of Agricultural Research of Tunisia, Carthage University, Tunis, Tunisia
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18
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Pflugbeil G, Affenzeller M, Tribsch A, Comes HP. Primary hybrid zone formation in Tephroseris helenitis (Asteraceae), following postglacial range expansion along the central Northern Alps. Mol Ecol 2021; 30:1704-1720. [PMID: 33548078 PMCID: PMC8048512 DOI: 10.1111/mec.15832] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 11/26/2022]
Abstract
Distinguishing between secondary versus primary hybrid zone formation remains a challenging task as, for instance, the time window in which these historical (vicariant) versus contemporary (environmental-selective) processes are distinguishable may be relatively narrow. Here, we examine the origin and structure of a transition zone between two subspecies of Tephroseris helenitis along the central Northern Alps, using molecular (AFLP) and morphological (achene type) data in combination with ecological niche models (ENMs) to hindcast ranges at the Last Glacial Maximum (LGM) and mid-Holocene. Samples were collected over a c. 350 km long transect, largely covered by ice during the LGM. Genetically nonadmixed individuals of subspp. helenitis versus salisburgensis dominated the westernmost versus eastern transect areas, with admixed individuals occurring in between. Clines for achene morphology and outlier loci potentially under climate-driven selection were steep, largely noncoincidental, and displaced to the east of the cline centre for neutral AFLPs. During the LGM, ssp. helenitis should have been able to persist in a refugium southwest of the transect, while suitable habitat for ssp. salisburgensis was apparently absent at this time. Together with patterns of genetic and clinal variation, our ENM data are suggestive of a primary hybrid zone that originated after the species' postglacial, eastward expansion. The observed clinal changes may thus reflect random/nonadaptive processes during expansion and selection on particular loci, and possibly achene type, in response to a long-term, west-to-east climate gradient in the direction of more stressful (e.g., wetter/cooler) conditions. Overall, this study adds to the vast hybrid zone literature a rare example of a hybrid zone caused by primary differentiation within a plant species, underlaid by historical range expansion.
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Affiliation(s)
- Georg Pflugbeil
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | | | - Andreas Tribsch
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | - Hans Peter Comes
- Department of Biosciences, University of Salzburg, Salzburg, Austria
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19
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Leroy T, Rougemont Q. Introduction to Population Genomics Methods. Methods Mol Biol 2021; 2222:287-324. [PMID: 33301100 DOI: 10.1007/978-1-0716-0997-2_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
High-throughput sequencing technologies have provided an unprecedented opportunity to study the different evolutionary forces that have shaped present-day patterns of genetic diversity, with important implications for many directions in plant biology research. To manage such massive quantities of sequencing data, biologists, however, need new additional skills in informatics and statistics. In this chapter, our objective is to introduce population genomics methods to beginners following a learning-by-doing strategy in order to help the reader to analyze the sequencing data by themselves. Conducted analyses cover several main areas of evolutionary biology, such as an initial description of the evolutionary history of a given species or the identification of genes targeted by natural or artificial selection. In addition to the practical advices, we performed re-analyses of two cases studies with different kind of data: a domesticated cereal (African rice) and a non-domesticated tree species (sessile oak). All the code needed to replicate this work is publicly available on github ( https://github.com/ThibaultLeroyFr/Intro2PopGenomics/ ).
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Affiliation(s)
- Thibault Leroy
- Montpellier Institute of Evolutionary Sciences (ISEM), Université de Montpellier, Montpellier, France. .,Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria.
| | - Quentin Rougemont
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Quebec, QC, Canada
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20
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Kaňuch P, Berggren Å, Cassel-Lundhagen A. A clue to invasion success: genetic diversity quickly rebounds after introduction bottlenecks. Biol Invasions 2020. [DOI: 10.1007/s10530-020-02426-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
AbstractOne of the fundamental questions in invasion biology is to understand the genetic mechanisms behind success or failure during the establishment of a species. However, major limitations to understanding are usually a lack of spatiotemporal population data and information on the populations’ colonisation history. In a large-scale, detailed study on the bush-cricket Metrioptera roeselii 70 groups of founders were introduced in areas outside the species’ distribution range. We examined how (1) the number of founders (2–32 individuals), (2) the time since establishment (7 or 15 years after introduction) and (3) possible gene flow affected establishment success and temporal genetic changes of the introduced populations. We found higher establishment success in introductions with larger propagule sizes but genetic diversity indices were only partly correlated to propagule size. As expected, introduced populations were more similar to their founder population the larger the propagule size was. However, even if apparent at first, most of the differentiation in the small propagule introductions disappeared over time. Surprisingly, genetic variability was regained to a level comparable to the large and outbreeding founder population only 15 generations after severe demographic bottlenecks. We suggest that the establishment of these populations could be a result of several mechanisms acting in synergy. Here, rapid increase in genetic diversity of few introductions could potentially be attributed to limited gene flow from adjacent populations, behavioural adaptations and/or even increased mutation rate. We present unique insights into genetic processes that point towards traits that are important for understanding species’ invasiveness.
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21
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Hellwig T, Abbo S, Sherman A, Coyne CJ, Saranga Y, Lev-Yadun S, Main D, Zheng P, Ophir R. Limited divergent adaptation despite a substantial environmental cline in wild pea. Mol Ecol 2020; 29:4322-4336. [PMID: 32964548 DOI: 10.1111/mec.15633] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 08/09/2020] [Accepted: 08/27/2020] [Indexed: 12/24/2022]
Abstract
Isolation by environment (IBE) is a widespread phenomenon in nature. It is commonly expected that the degree of difference among environments is proportional to the level of divergence between populations in their respective environments. It is therefore assumed that a species' genetic diversity displays a pattern of IBE in the presence of a strong environmental cline if gene flow does not mitigate isolation. We tested this common assumption by analysing the genetic diversity and demographic history of Pisum fulvum, which inhabits contrasting habitats in the southern Levant and is expected to display only minor migration rates between populations, making it an ideal test case. Ecogeographical and subpopulation structure were analysed and compared. The correlation of genetic with environmental distances was calculated to test the effect of isolation by distance and IBE and detect the main drivers of these effects. Historical effective population size was estimated using stairway plot. Limited overlap of ecogeographical and genetic clustering was observed, and correlation between genetic and environmental distances was statistically significant but small. We detected a sharp decline of effective population size during the last glacial period. The low degree of IBE may be the result of genetic drift due to a past bottleneck. Our findings contradict the expectation that strong environmental clines cause IBE in the absence of extensive gene flow.
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Affiliation(s)
- Timo Hellwig
- Institute of Plant Sciences and Genetics, The Hebrew University of Jerusalem, Rehovot, Israel
- Institute of Plant Sciences, Agricultural Research Organization - Volcani Center, Rishon LeZion, Israel
| | - Shahal Abbo
- Institute of Plant Sciences and Genetics, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Amir Sherman
- Institute of Plant Sciences, Agricultural Research Organization - Volcani Center, Rishon LeZion, Israel
| | | | - Yehoshua Saranga
- Institute of Plant Sciences and Genetics, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Simcha Lev-Yadun
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa-Oranim, Tivon, Israel
| | - Dorrie Main
- Department of Horticulture, Washington State University, Pullman, WA, USA
| | - Ping Zheng
- Department of Horticulture, Washington State University, Pullman, WA, USA
| | - Ron Ophir
- Institute of Plant Sciences, Agricultural Research Organization - Volcani Center, Rishon LeZion, Israel
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22
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Zanin M, Gonzalez-Borrajo N, ChÁvez C, Rubio Y, Harmsen B, Keller C, Villalva P, Srbek-Araujo AC, Costa LP, Palomares F. The differential genetic signatures related to climatic landscapes for jaguars and pumas on a continental scale. Integr Zool 2020; 16:2-18. [PMID: 32929877 DOI: 10.1111/1749-4877.12486] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Modern and paleoclimate changes may have altered species dynamics by shifting species' niche suitability over space and time. We analyze whether the current genetic structure and isolation of the two large American felids, jaguar (Panthera onca) and puma (Puma concolor), are mediated by changes in climatic suitability and connection routes over modern and paleoclimatic landscapes. We estimate species distribution under 5 climatic landscapes (modern, Holocene, last maximum glaciations [LMG], average suitability, and climatic instability) and correlate them with individuals' genetic isolation through causal modeling on a resemblance matrix. Both species exhibit genetic isolation patterns correlated with LMG climatic suitability, suggesting that these areas may have worked as "allele refuges." However, the jaguar showed higher vulnerability to climate changes, responding to modern climatic suitability and connection routes, whereas the puma showed a continuous and gradual transition of genetic variation. Despite differential responsiveness to climate change, both species are subjected to the climatic effects on genetic configuration, which may make them susceptible to future climatic changes, since these are progressing faster and with higher intensity than changes in the paleoclimate. Thus, the effects of climatic changes should be considered in the design of conservation strategies to ensure evolutionary and demographic processes mediated by gene flow for both species.
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Affiliation(s)
- Marina Zanin
- Biology Department, Federal University of Maranhão, São Luís, Brazil
| | - Noa Gonzalez-Borrajo
- Departamento de Biologia de la Conservación, Estación Biológica de Doñana, Sevilla, Spain
| | - Cuauhtémoc ChÁvez
- Departamento de Ciencias Ambientales, Universidad Autónoma Metropolitana, Mexico City, Mexico
| | - Yamel Rubio
- Escuela de Biologia, Universidad Autónoma de Sinaloa, Culiacán, Mexico
| | | | - Claudia Keller
- Biodiversity Coordination, Amazon Research Institute, Manaus, Brazil
| | - Pablo Villalva
- Departamento de Biologia de la Conservación, Estación Biológica de Doñana, Sevilla, Spain
| | | | - Leonora Pires Costa
- Biological Sciences Department, Federal University of Espírito Santo, Vitória, Brazil
| | - Francisco Palomares
- Departamento de Biologia de la Conservación, Estación Biológica de Doñana, Sevilla, Spain
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23
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Visser J, Robinson T, Jansen van Vuuren B. Spatial genetic structure in the rock hyrax (Procavia capensis) across the Namaqualand and western Fynbos areas of South Africa — a mitochondrial and microsatellite perspective. CAN J ZOOL 2020. [DOI: 10.1139/cjz-2019-0154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The interplay between biotic and abiotic environments is increasingly recognized as a major determinant of spatial genetic patterns. Among spatial genetic studies, saxicolous or rock-dwelling species remain underrepresented in spite of their strict dependence on landscape structure. Here we investigated patterns and processes operating at different spatial (fine and regional scales) and time scales (using mitochondrial and microsatellite markers) in the rock hyrax (Procavia capensis (Pallas, 1766)). Our focus was on the western seaboard of South Africa and included two recognized biodiversity hotspots (Cape Floristic Region and Succulent Karoo). At fine spatial scale, significant genetic structure was present between four rocky outcrops in an isolated population, likely driven by the social system of this species. At a broader spatial scale, ecological dependence on rocky habitat and population-level processes, in conjunction with landscape structure, appeared to be the main drivers of genetic diversity and structure. Large areas devoid of suitable rocky habitat (e.g., the Knersvlakte, Sandveld, and Cape Flats, South Africa) represent barriers to gene flow in the species, although genetic clusters closely follow climatic, geological, and phytogeographic regions, possibly indicating ecological specialization or adaptation as contributing factors enforcing isolation. Taken together, our study highlights the need to consider both intrinsic and extrinsic factors when investigating spatial genetic structures within species.
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Affiliation(s)
- J.H. Visser
- Department of Botany and Zoology, University of Stellenbosch, Private Bag XI, Matieland 7602, South Africa
| | - T.J. Robinson
- Department of Botany and Zoology, University of Stellenbosch, Private Bag XI, Matieland 7602, South Africa
| | - B. Jansen van Vuuren
- Centre for Ecological Genomics and Wildlife Conservation, Department of Zoology, University of Johannesburg, P.O. Box 524, Auckland Park 2000, South Africa
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24
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Currat M, Arenas M, Quilodràn CS, Excoffier L, Ray N. SPLATCHE3: simulation of serial genetic data under spatially explicit evolutionary scenarios including long-distance dispersal. Bioinformatics 2020; 35:4480-4483. [PMID: 31077292 PMCID: PMC6821363 DOI: 10.1093/bioinformatics/btz311] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/18/2019] [Accepted: 04/29/2019] [Indexed: 01/25/2023] Open
Abstract
SUMMARY SPLATCHE3 simulates genetic data under a variety of spatially explicit evolutionary scenarios, extending previous versions of the framework. The new capabilities include long-distance migration, spatially and temporally heterogeneous short-scale migrations, alternative hybridization models, simulation of serial samples of genetic data and a large variety of DNA mutation models. These implementations have been applied independently to various studies, but grouped together in the current version. AVAILABILITY AND IMPLEMENTATION SPLATCHE3 is written in C++ and is freely available for non-commercial use from the website http://www.splatche.com/splatche3. It includes console versions for Linux, MacOs and Windows and a user-friendly GUI for Windows, as well as detailed documentation and ready-to-use examples.
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Affiliation(s)
- Mathias Currat
- Laboratory of Anthropology, Genetics and Peopling History, Department of Genetics and Evolution - Anthropology Unit, University of Geneva, Geneva 1205, Switzerland.,Institute of Genetics and Genomics in Geneva (IGE3), University of Geneva, Geneva 1211, Switzerland
| | - Miguel Arenas
- Department of Biochemistry, Genetics and Immunology, Vigo 36310, Spain.,Biomedical Research Center (CINBIO), University of Vigo, Vigo 36310, Spain
| | - Claudio S Quilodràn
- Laboratory of Anthropology, Genetics and Peopling History, Department of Genetics and Evolution - Anthropology Unit, University of Geneva, Geneva 1205, Switzerland
| | - Laurent Excoffier
- Computational and Molecular Population Genetics Laboratory, Institute of Ecology and Evolution, University of Bern, Bern 3012, Switzerland.,Swiss Institute of Bioinformatics, Lausanne 1015, Switzerland
| | - Nicolas Ray
- Institute of Global Health, GeoHealth Group, University of Geneva, Geneva 1205, Switzerland.,Institute for Environmental Sciences, University of Geneva, Geneva 1205, Switzerland
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25
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Abstract
The ectomycorrhizal fungus Tuber magnatum produces the white truffle appreciated worldwide for its unique aroma. With respect to other Tuber spp. of economic interest, T. magnatum presents a narrower geographical range. This species has, in fact, long been considered endemic to Italy. However, over the last few decades several reports have documented the presence of white truffles in different Mediterranean countries and in particular in various areas of south-east Europe. In this study, samples from several Pannonian and Balkan countries such as Hungary, Serbia, Romania, Bulgaria and Greece have been collected and genotyped with microsatellite markers and the data merged with those available for Italian populations. Our objectives were to test whether Italian and south-east European populations are differentiated and to evaluate the genetic diversity of T. magnatum all over its distributional range. We show the genetic structure of T. magnatum populations with the differentiation of four main groups: northern Italy, central-northern Italy, southern Italy and the Balkan/Pannonian region. The present study allowed us to refine the evolutionary history of T. magnatum and track the possible post-glacial expansion route of this species. The assessment of T. magnatum’s genetic structure is not only of scientific relevance, but it is also important for the conservation and market traceability of this prestigious fungus.
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26
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Chambers EA, Hillis DM. The Multispecies Coalescent Over-Splits Species in the Case of Geographically Widespread Taxa. Syst Biol 2020; 69:184-193. [PMID: 31180508 DOI: 10.1093/sysbio/syz042] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 05/22/2019] [Accepted: 05/24/2019] [Indexed: 11/14/2022] Open
Abstract
Many recent species delimitation studies rely exclusively on limited analyses of genetic data analyzed under the multispecies coalescent (MSC) model, and results from these studies often are regarded as conclusive support for taxonomic changes. However, most MSC-based species delimitation methods have well-known and often unmet assumptions. Uncritical application of these genetic-based approaches (without due consideration of sampling design, the effects of a priori group designations, isolation by distance, cytoplasmic-nuclear mismatch, and population structure) can lead to over-splitting of species. Here, we argue that in many common biological scenarios, researchers must be particularly cautious regarding these limitations, especially in cases of well-studied, geographically variable, and parapatrically distributed species complexes. We consider these points with respect to a historically controversial species group, the American milksnakes (Lampropeltis triangulum complex), using genetic data from a recent analysis (Ruane et al. 2014). We show that over-reliance on the program Bayesian Phylogenetics and Phylogeography, without adequate consideration of its assumptions and of sampling limitations, resulted in over-splitting of species in this study. Several of the hypothesized species of milksnakes instead appear to represent arbitrary slices of continuous geographic clines. We conclude that the best available evidence supports three, rather than seven, species within this complex. More generally, we recommend that coalescent-based species delimitation studies incorporate thorough analyses of geographic variation and carefully examine putative contact zones among delimited species before making taxonomic changes.
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Affiliation(s)
- E Anne Chambers
- Department of Integrative Biology and Biodiversity Center, The University of Texas at Austin, Austin, TX 78712, USA
| | - David M Hillis
- Department of Integrative Biology and Biodiversity Center, The University of Texas at Austin, Austin, TX 78712, USA
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27
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DeSilva R, Dodd RS. Fragmented and isolated: limited gene flow coupled with weak isolation by environment in the paleoendemic giant sequoia (Sequoiadendron giganteum). AMERICAN JOURNAL OF BOTANY 2020; 107:45-55. [PMID: 31883111 DOI: 10.1002/ajb2.1406] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 11/13/2019] [Indexed: 06/10/2023]
Abstract
PREMISE Patterns of genetic structure across a species' range reflect the long-term interplay between genetic drift, gene flow, and selection. Given the importance of gene flow in preventing the loss of diversity through genetic drift among spatially isolated populations, understanding the dynamics of gene flow and the factors that influence connectivity across a species' range is a major goal for conservation of genetic diversity. Here we present a detailed look at gene flow dynamics of Sequoiadendron giganteum, a paleoendemic tree species that will likely face numerous threats due to climate change. METHODS We used microsatellite markers to examine nineteen populations of S. giganteum for patterns of genetic structure and to estimate admixture and rates of gene flow between eight population pairs. Also, we used Generalized Dissimilarity Models to elucidate landscape factors that shape genetic differentiation among populations. RESULTS We found minimal gene flow between adjacent groves in the northern disjunct range. In most of the southern portion of the range, groves showed a signal of connectivity which degrades to isolation in the extreme south. Geographic distance was the most important predictor of genetic dissimilarity across the range, with environmental conditions related to precipitation and temperature explaining a small, but significant, portion of the genetic variance. CONCLUSIONS Due to their isolation and unique genetic composition, northern populations of S. giganteum should be considered a high conservation priority. In this region, we suggest germplasm conservation as well as restoration planting to enhance genetic diversity.
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Affiliation(s)
- Rainbow DeSilva
- Department of Environmental Science, Policy, and Management, University of California at Berkeley, Berkeley, California, USA
| | - Richard S Dodd
- Department of Environmental Science, Policy, and Management, University of California at Berkeley, Berkeley, California, USA
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28
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Menchaca A, Rossi NA, Froidevaux J, Dias-Freedman I, Caragiulo A, Wultsch C, Harmsen B, Foster R, de la Torre JA, Medellin RA, Rabinowitz S, Amato G. Population genetic structure and habitat connectivity for jaguar (Panthera onca) conservation in Central Belize. BMC Genet 2019; 20:100. [PMID: 31881935 PMCID: PMC6933898 DOI: 10.1186/s12863-019-0801-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 12/15/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Connectivity among jaguar (Panthera onca) populations will ensure natural gene flow and the long-term survival of the species throughout its range. Jaguar conservation efforts have focused primarily on connecting suitable habitat in a broad-scale. Accelerated habitat reduction, human-wildlife conflict, limited funding, and the complexity of jaguar behaviour have proven challenging to maintain connectivity between populations effectively. Here, we used non-invasive genetic sampling and individual-based conservation genetic analyses to assess genetic diversity and levels of genetic connectivity between individuals in the Cockscomb Basin Wildlife Sanctuary and the Maya Forest Corridor. We used expert knowledge and scientific literature to develop models of landscape permeability based on circuit theory with fine-scale landscape features as ecosystem types, distance to human settlements and roads to predict the most probable jaguar movement across central Belize. RESULTS We used 12 highly polymorphic microsatellite loci to identify 50 individual jaguars. We detected high levels of genetic diversity across loci (HE = 0.61, HO = 0.55, and NA = 9.33). Using Bayesian clustering and multivariate models to assess gene flow and genetic structure, we identified one single group of jaguars (K = 1). We identified critical areas for jaguar movement that fall outside the boundaries of current protected areas in central Belize. We detected two main areas of high landscape permeability in a stretch of approximately 18 km between Sittee River Forest Reserve and Manatee Forest Reserve that may increase functional connectivity and facilitate jaguar dispersal from and to Cockscomb Basin Wildlife Sanctuary. Our analysis provides important insights on fine-scale genetic and landscape connectivity of jaguars in central Belize, an area of conservation concern. CONCLUSIONS The results of our study demonstrate high levels of relatively recent gene flow for jaguars between two study sites in central Belize. Our landscape analysis detected corridors of expected jaguar movement between the Cockscomb Basin Wildlife Sanctuary and the Maya Forest Corridor. We highlight the importance of maintaining already established corridors and consolidating new areas that further promote jaguar movement across suitable habitat beyond the boundaries of currently protected areas. Continued conservation efforts within identified corridors will further maintain and increase genetic connectivity in central Belize.
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Affiliation(s)
- Angelica Menchaca
- School of Biological Sciences, the University of Bristol, Bristol, UK.
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York City, USA.
| | - Natalia A Rossi
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York City, USA
- The Wildlife Conservation Society, New York City, USA
| | - Jeremy Froidevaux
- School of Biological Sciences, the University of Bristol, Bristol, UK
| | | | - Anthony Caragiulo
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York City, USA
| | - Claudia Wultsch
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York City, USA
- City University of New York, New York City, USA
| | - Bart Harmsen
- Panthera, New York City, USA
- Environmental Research Institute, University of Belize, Belmopan, Belize
- Southampton University, Southampton, UK
| | - Rebecca Foster
- Panthera, New York City, USA
- Southampton University, Southampton, UK
| | - J Antonio de la Torre
- School of Environmental and Geographical Sciences, University of Nottingham Malaysia, Semenyih, Malaysia
| | - Rodrigo A Medellin
- Instituto de Ecologia, Universidad Nacional Autonoma de Mexico, Mexico City, Mexico
| | - Salisa Rabinowitz
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York City, USA
| | - George Amato
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York City, USA.
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29
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Homola JJ, Loftin CS, Kinnison MT. Landscape genetics reveals unique and shared effects of urbanization for two sympatric pool-breeding amphibians. Ecol Evol 2019; 9:11799-11823. [PMID: 31695889 PMCID: PMC6822048 DOI: 10.1002/ece3.5685] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 08/26/2019] [Accepted: 08/30/2019] [Indexed: 01/05/2023] Open
Abstract
Metapopulation-structured species can be negatively affected when landscape fragmentation impairs connectivity. We investigated the effects of urbanization on genetic diversity and gene flow for two sympatric amphibian species, spotted salamanders (Ambystoma maculatum) and wood frogs (Lithobates sylvaticus), across a large (>35,000 km2) landscape in Maine, USA, containing numerous natural and anthropogenic gradients. Isolation-by-distance (IBD) patterns differed between the species. Spotted salamanders showed a linear and relatively high variance relationship between genetic and geographic distances (r = .057, p < .001), whereas wood frogs exhibited a strongly nonlinear and lower variance relationship (r = 0.429, p < .001). Scale dependence analysis of IBD found gene flow has its most predictable influence (strongest IBD correlations) at distances up to 9 km for spotted salamanders and up to 6 km for wood frogs. Estimated effective migration surfaces revealed contrasting patterns of high and low genetic diversity and gene flow between the two species. Population isolation, quantified as the mean IBD residuals for each population, was associated with local urbanization and less genetic diversity in both species. The influence of geographic proximity and urbanization on population connectivity was further supported by distance-based redundancy analysis and multiple matrix regression with randomization. Resistance surface modeling found interpopulation connectivity to be influenced by developed land cover, light roads, interstates, and topography for both species, plus secondary roads and rivers for wood frogs. Our results highlight the influence of anthropogenic landscape features within the context of natural features and broad spatial genetic patterns, in turn supporting the premise that while urbanization significantly restricts interpopulation connectivity for wood frogs and spotted salamanders, specific landscape elements have unique effects on these two sympatric species.
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Affiliation(s)
| | - Cynthia S. Loftin
- Maine Cooperative Fish and Wildlife Research UnitU.S. Geological SurveyOronoMEUSA
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30
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Branca A, Le Ru B, Calatayud PA, Obonyo J, Musyoka B, Capdevielle-Dulac C, Kaiser-Arnauld L, Silvain JF, Gauthier J, Paillusson C, Gayral P, Herniou EA, Dupas S. Relative Influence of Host, Wolbachia, Geography and Climate on the Genetic Structure of the Sub-saharan Parasitic Wasp Cotesia sesamiae. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00309] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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31
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Winkler DE, Chapin KJ, François O, Garmon JD, Gaut BS, Huxman TE. Multiple introductions and population structure during the rapid expansion of the invasive Sahara mustard ( Brassica tournefortii). Ecol Evol 2019; 9:7928-7941. [PMID: 31380061 PMCID: PMC6662425 DOI: 10.1002/ece3.5239] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 04/13/2019] [Accepted: 04/14/2019] [Indexed: 12/23/2022] Open
Abstract
The specific mechanisms that result in the success of any species invasion case are difficult to document. Reproductive strategies are often cited as a primary driver of invasive success, with human activities further facilitating invasions by, for example, acting as seed vectors for dispersal via road, train, air, and marine traffic, and by producing efficient corridors for movement including canals, drainages, and roadways. Sahara mustard (Brassica tournefortii) is a facultative autogamous annual native to Eurasia that has rapidly invaded the southwestern United States within the past century, displacing natives, and altering water-limited landscapes in the southwest. We used a genotyping-by-sequencing approach to study the population structure and spatial geography of Sahara mustard from 744 individuals from 52 sites across the range of the species' invasion. We also used herbaria records to model range expansion since its initial introduction in the 1920s. We found that Sahara mustard occurs as three populations in the United States unstructured by geography, identified three introduction sites, and combined herbaria records with genomic analyses to map the spread of the species. Low genetic diversity and linkage disequilibrium are consistent with self-fertilization, which likely promoted rapid invasive spread. Overall, we found that Sahara mustard experienced atypical expansion patterns, with a relatively constant rate of expansion and without the lag phase that is typical of many invasive species.
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Affiliation(s)
- Daniel E. Winkler
- Department of Ecology and Evolutionary BiologyUniversity of California, IrvineIrvineCalifornia
- U.S. Geological SurveySouthwest Biological Science CenterMoabUtah
| | - Kenneth J. Chapin
- Department of Ecology and Evolutionary BiologyUniversity of California, Los AngelesLos AngelesCalifornia
- Department of Ecology and Evolutionary BiologyUniversity of ArizonaTucsonArizona
| | | | | | - Brandon S. Gaut
- Department of Ecology and Evolutionary BiologyUniversity of California, IrvineIrvineCalifornia
| | - Travis E. Huxman
- Department of Ecology and Evolutionary BiologyUniversity of California, IrvineIrvineCalifornia
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32
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Thompson LM, Klütsch CFC, Manseau M, Wilson PJ. Spatial differences in genetic diversity and northward migration suggest genetic erosion along the boreal caribou southern range limit and continued range retraction. Ecol Evol 2019; 9:7030-7046. [PMID: 31380031 PMCID: PMC6662424 DOI: 10.1002/ece3.5269] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 04/24/2019] [Accepted: 04/26/2019] [Indexed: 11/12/2022] Open
Abstract
With increasing human activities and associated landscape changes, distributions of terrestrial mammals become fragmented. These changes in distribution are often associated with reduced population sizes and loss of genetic connectivity and diversity (i.e., genetic erosion) which may further diminish a species' ability to respond to changing environmental conditions and lead to local population extinctions. We studied threatened boreal caribou (Rangifer tarandus caribou) populations across their distribution in Ontario/Manitoba (Canada) to assess changes in genetic diversity and connectivity in areas of high and low anthropogenic activity. Using data from >1,000 caribou and nine microsatellite loci, we assessed population genetic structure, genetic diversity, and recent migration rates using a combination of network and population genetic analyses. We used Bayesian clustering analyses to identify population genetic structure and explored spatial and temporal variation in those patterns by assembling networks based on R ST and F ST as historical and contemporary genetic edge distances, respectively. The Bayesian clustering analyses identified broad-scale patterns of genetic structure and closely aligned with the R ST network. The F ST network revealed substantial contemporary genetic differentiation, particularly in areas presenting contemporary anthropogenic disturbances and habitat fragmentation. In general, relatively lower genetic diversity and greater genetic differentiation were detected along the southern range limit, differing from areas in the northern parts of the distribution. Moreover, estimation of migration rates suggested a northward movement of animals away from the southern range limit. The patterns of genetic erosion revealed in our study suggest ongoing range retraction of boreal caribou in central Canada.
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Affiliation(s)
- Laura M. Thompson
- Natural Resources DNA Profiling and Forensic CentreTrent UniversityPeterboroughOntarioCanada
- Present address:
U.S. Geological SurveyNational Climate Adaptation Science CenterRestonVirginia
| | - Cornelya F. C. Klütsch
- Natural Resources DNA Profiling and Forensic CentreTrent UniversityPeterboroughOntarioCanada
- Present address:
Division of Environmental Research in the Barents RegionNorwegian Institute of Bioeconomy Research (NIBIO)SvanvikNorway
| | - Micheline Manseau
- Natural Resources DNA Profiling and Forensic CentreTrent UniversityPeterboroughOntarioCanada
- Natural Resources InstituteUniversity of ManitobaWinnipegManitobaCanada
- Landscape Science and TechnologyEnvironment and Climate Change CanadaOttawaOntarioCanada
| | - Paul J. Wilson
- Natural Resources DNA Profiling and Forensic CentreTrent UniversityPeterboroughOntarioCanada
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33
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Foote AD, Martin MD, Louis M, Pacheco G, Robertson KM, Sinding MHS, Amaral AR, Baird RW, Baker CS, Ballance L, Barlow J, Brownlow A, Collins T, Constantine R, Dabin W, Dalla Rosa L, Davison NJ, Durban JW, Esteban R, Ferguson SH, Gerrodette T, Guinet C, Hanson MB, Hoggard W, Matthews CJD, Samarra FIP, de Stephanis R, Tavares SB, Tixier P, Totterdell JA, Wade P, Excoffier L, Gilbert MTP, Wolf JBW, Morin PA. Killer whale genomes reveal a complex history of recurrent admixture and vicariance. Mol Ecol 2019; 28:3427-3444. [PMID: 31131963 DOI: 10.1111/mec.15099] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 04/06/2019] [Accepted: 04/08/2019] [Indexed: 02/06/2023]
Abstract
Reconstruction of the demographic and evolutionary history of populations assuming a consensus tree-like relationship can mask more complex scenarios, which are prevalent in nature. An emerging genomic toolset, which has been most comprehensively harnessed in the reconstruction of human evolutionary history, enables molecular ecologists to elucidate complex population histories. Killer whales have limited extrinsic barriers to dispersal and have radiated globally, and are therefore a good candidate model for the application of such tools. Here, we analyse a global data set of killer whale genomes in a rare attempt to elucidate global population structure in a nonhuman species. We identify a pattern of genetic homogenisation at lower latitudes and the greatest differentiation at high latitudes, even between currently sympatric lineages. The processes underlying the major axis of structure include high drift at the edge of species' range, likely associated with founder effects and allelic surfing during postglacial range expansion. Divergence between Antarctic and non-Antarctic lineages is further driven by ancestry segments with up to four-fold older coalescence time than the genome-wide average; relicts of a previous vicariance during an earlier glacial cycle. Our study further underpins that episodic gene flow is ubiquitous in natural populations, and can occur across great distances and after substantial periods of isolation between populations. Thus, understanding the evolutionary history of a species requires comprehensive geographic sampling and genome-wide data to sample the variation in ancestry within individuals.
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Affiliation(s)
- Andrew D Foote
- CMPG, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
| | | | - Marie Louis
- Department of Biology, Section for Evolutionary Genomics, University of Copenhagen, Copenhagen, Denmark.,Scottish Oceans Institute, East Sands, University of St. Andrews, St. Andrews, UK
| | - George Pacheco
- Department of Biology, Section for Evolutionary Genomics, University of Copenhagen, Copenhagen, Denmark
| | - Kelly M Robertson
- Marine Mammal and Turtle Division, National Marine Fisheries Service, National Oceanographic and Atmospheric Administration, Southwest Fisheries Science Center, La Jolla, California
| | - Mikkel-Holger S Sinding
- Department of Biology, Section for Evolutionary Genomics, University of Copenhagen, Copenhagen, Denmark.,Greenland Institute of Natural Resources, Nuuk, Greenland
| | - Ana R Amaral
- American Museum of Natural History, New York City, New York.,Faculdade de Ciências Universidade de Lisboa, Centre for Ecology, Evolution and Environmental Changes, Lisboa, Portugal
| | | | - Charles Scott Baker
- Department of Fisheries and Wildlife, Marine Mammal Institute, Oregon State University, Newport, Oregon.,School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Lisa Ballance
- Marine Mammal and Turtle Division, National Marine Fisheries Service, National Oceanographic and Atmospheric Administration, Southwest Fisheries Science Center, La Jolla, California
| | - Jay Barlow
- Marine Mammal and Turtle Division, National Marine Fisheries Service, National Oceanographic and Atmospheric Administration, Southwest Fisheries Science Center, La Jolla, California
| | - Andrew Brownlow
- Scottish Marine Animal Stranding Scheme, SRUC Veterinary Services Drummondhill, Inverness, UK
| | - Tim Collins
- Ocean Giants Program, Wildlife Conservation Society, New York City, New York
| | | | - Willy Dabin
- Observatoire Pelagis, Université de La Rochelle-CNRS, La Rochelle, France
| | - Luciano Dalla Rosa
- Laboratório de Ecologia e Conservação da Megafauna Marinha, Instituto de Oceanografia, Universidade Federal do Rio Grande, Rio Grande, Brazil
| | - Nicholas J Davison
- Scottish Marine Animal Stranding Scheme, SRUC Veterinary Services Drummondhill, Inverness, UK
| | - John W Durban
- Marine Mammal and Turtle Division, National Marine Fisheries Service, National Oceanographic and Atmospheric Administration, Southwest Fisheries Science Center, La Jolla, California
| | - Ruth Esteban
- CIRCE, Conservation, Information and Research on Cetaceans, Algeciras, Spain
| | | | - Tim Gerrodette
- Marine Mammal and Turtle Division, National Marine Fisheries Service, National Oceanographic and Atmospheric Administration, Southwest Fisheries Science Center, La Jolla, California
| | - Christophe Guinet
- Centre d'Etudes Biologiques de Chizé (CEBC), CNRS-ULR, UMR, Chizé, France
| | - M Bradley Hanson
- National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Northwest Fisheries Science Center, Seattle, Washington
| | - Wayne Hoggard
- National Marine Fisheries Service, NOAA, Southeast Fisheries Science Center, Pascagoula, Mississippi
| | | | | | - Renaud de Stephanis
- CIRCE, Conservation, Information and Research on Cetaceans, Algeciras, Spain
| | - Sara B Tavares
- Scottish Oceans Institute, East Sands, University of St. Andrews, St. Andrews, UK
| | - Paul Tixier
- Centre d'Etudes Biologiques de Chizé (CEBC), CNRS-ULR, UMR, Chizé, France.,School of Life and Environmental Sciences (Burwood Campus), Deakin University, Geelong, Victoria, Australia
| | - John A Totterdell
- Marine Information and Research Group-Australia (MIRG), Quinns Rocks, Western Australia, Australia
| | - Paul Wade
- National Marine Mammal Laboratory, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Alaska Fisheries Science Center, Seattle, Washington
| | - Laurent Excoffier
- CMPG, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
| | - M Thomas P Gilbert
- NTNU University Museum, Trondheim, Norway.,Department of Biology, Section for Evolutionary Genomics, University of Copenhagen, Copenhagen, Denmark
| | - Jochen B W Wolf
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Planegg-Martinsried, Germany.,Department of Evolutionary Biology, Science of Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Phillip A Morin
- Marine Mammal and Turtle Division, National Marine Fisheries Service, National Oceanographic and Atmospheric Administration, Southwest Fisheries Science Center, La Jolla, California
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34
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Genetic Analysis of a Cryptic Contact Zone between Mitochondrial Clades of the Eastern Red-Backed Salamander, Plethodon cinereus. J HERPETOL 2019. [DOI: 10.1670/18-088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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35
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The evolutionary history of the Cape hare (Lepus capensis sensu lato): insights for systematics and biogeography. Heredity (Edinb) 2019; 123:634-646. [PMID: 31073237 DOI: 10.1038/s41437-019-0229-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 04/11/2019] [Accepted: 04/19/2019] [Indexed: 12/27/2022] Open
Abstract
Inferring the phylogeography of species with large distributions helps deciphering major diversification patterns that may occur in parallel across taxa. Here, we infer the evolutionary history of the Cape hare, Lepus capensis sensu lato, a species distributed from southern Africa to Asia, by analyzing variation at 18 microsatellites and 9 DNA (1 mitochondrial and 8 nuclear) sequenced loci, from field and museum-collected samples. Using a combination of assignment and coalescent-based methods, we show that the Cape hare is composed of five evolutionary lineages, distributed in distinct biogeographic regions-north-western Africa, eastern Africa, southern Africa, the Near East and the Arabian Peninsula. A deep phylogenetic break possibly dating to the Early Pleistocene was inferred between the African and Asian L. capensis groups, and the latter appear more closely related to other Eurasian hare species than to African Cape hares. The inferred phylogeographic structure is shared by numerous taxa distributed across the studied range, suggesting that environmental changes, such as the progressive aridification of the Saharo-Arabian desert and the fluctuations of savannah habitats in Sub-Saharan Africa, had comparable impacts across species. Fine-scale analyses of the western Sahara-Sahel populations showed rich fragmentation patterns for mitochondrial DNA but not for microsatellites, compatible with the environmental heterogeneity of the region and female philopatry. The complex evolutionary history of L. capensis sensu lato, which possibly includes interspecific gene flow, is not reflected by taxonomy. Integrating evolutionary inference contributes to an improved characterization of biodiversity, which is fundamental to foster the conservation of relevant evolutionary units.
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36
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Fine-scale genetic structure and conservation status of American badgers at their northwestern range periphery. CONSERV GENET 2019. [DOI: 10.1007/s10592-019-01192-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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37
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Wang J. A parsimony estimator of the number of populations from a STRUCTURE‐like analysis. Mol Ecol Resour 2019; 19:970-981. [DOI: 10.1111/1755-0998.13000] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 01/15/2019] [Indexed: 01/21/2023]
Affiliation(s)
- Jinliang Wang
- Institute of Zoology Zoological Society of London London UK
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38
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Bradbury D, Binks RM, Coates DJ, Byrne M. Conservation genomics of range disjunction in a global biodiversity hotspot: a case study of Banksia biterax (Proteaceae) in southwestern Australia. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz050] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Donna Bradbury
- Biodiversity and Conservation Science; Department of Biodiversity, Conservation & Attractions, Kensington, WA, Australia
| | - Rachel M Binks
- Biodiversity and Conservation Science; Department of Biodiversity, Conservation & Attractions, Kensington, WA, Australia
| | - David J Coates
- Biodiversity and Conservation Science; Department of Biodiversity, Conservation & Attractions, Kensington, WA, Australia
| | - Margaret Byrne
- Biodiversity and Conservation Science; Department of Biodiversity, Conservation & Attractions, Kensington, WA, Australia
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39
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Grieneisen LE, Charpentier MJE, Alberts SC, Blekhman R, Bradburd G, Tung J, Archie EA. Genes, geology and germs: gut microbiota across a primate hybrid zone are explained by site soil properties, not host species. Proc Biol Sci 2019; 286:20190431. [PMID: 31014219 PMCID: PMC6501927 DOI: 10.1098/rspb.2019.0431] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 04/02/2019] [Indexed: 12/19/2022] Open
Abstract
Gut microbiota in geographically isolated host populations are often distinct. These differences have been attributed to between-population differences in host behaviours, environments, genetics and geographical distance. However, which factors are most important remains unknown. Here, we fill this gap for baboons by leveraging information on 13 environmental variables from 14 baboon populations spanning a natural hybrid zone. Sampling across a hybrid zone allowed us to additionally test whether phylosymbiosis (codiversification between hosts and their microbiota) is detectable in admixed, closely related primates. We found little evidence of genetic effects: none of host genetic ancestry, host genetic relatedness nor genetic distance between host populations were strong predictors of baboon gut microbiota. Instead, gut microbiota were best explained by the baboons' environments, especially the soil's geologic history and exchangeable sodium. Indeed, soil effects were 15 times stronger than those of host-population FST, perhaps because soil predicts which foods are present, or because baboons are terrestrial and consume soil microbes incidentally with their food. Our results support an emerging picture in which environmental variation is the dominant predictor of host-associated microbiomes. We are the first to show that such effects overshadow host species identity among members of the same primate genus.
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Affiliation(s)
- Laura E. Grieneisen
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Biology, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Marie J. E. Charpentier
- Institut des Sciences de l'Evolution de Montpellier, Université Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Susan C. Alberts
- Department of Biology, Duke University, Durham, NC 27708, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
- Institute for Primate Research, National Museums of Kenya, Nairobi 00502, Kenya
| | - Ran Blekhman
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Minneapolis, MN 55455, USA
| | - Gideon Bradburd
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Jenny Tung
- Department of Biology, Duke University, Durham, NC 27708, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC 27708, USA
- Institute for Primate Research, National Museums of Kenya, Nairobi 00502, Kenya
| | - Elizabeth A. Archie
- Department of Biology, University of Notre Dame, Notre Dame, IN 46556, USA
- Institute for Primate Research, National Museums of Kenya, Nairobi 00502, Kenya
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40
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Pleistocene-dated biogeographic barriers drove divergence within the Australo-Papuan region in a sex-specific manner: an example in a widespread Australian songbird. Heredity (Edinb) 2019; 123:608-621. [PMID: 30874632 PMCID: PMC6972870 DOI: 10.1038/s41437-019-0206-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 02/11/2019] [Accepted: 02/23/2019] [Indexed: 11/09/2022] Open
Abstract
Understanding how environmental change has shaped species evolution can inform predictions of how future climate change might continue to do so. Research of widespread biological systems spanning multiple climates that have been subject to environmental change can yield generalizable inferences about the neutral and adaptive processes driving lineage divergence during periods of environmental change. We contribute to the growing body of multi-locus phylogeographic studies investigating the effect of Pleistocene climate change on species evolution by focusing on a widespread Australo-Papuan songbird with several mitochondrial lineages that diverged during the Pleistocene, the grey shrike-thrush (Colluricincla harmonica). We employed multi-locus phylogenetic, population genetic and coalescent analyses to (1) assess whether nuclear genetic diversity suggests a history congruent with that based on phenotypically defined subspecies ranges, mitochondrial clade boundaries and putative biogeographical barriers, (2) estimate genetic diversity within and genetic differentiation and gene flow among regional populations and (3) estimate population divergence times. The five currently recognized subspecies of grey shrike-thrush are genetically differentiated in nuclear and mitochondrial genomes, but connected by low levels of gene flow. Divergences among these populations are concordant with recognized historical biogeographical barriers and date to the Pleistocene. Discordance in the order of population divergence events based on mitochondrial and nuclear genomes suggests a history of sex-biased gene flow and/or mitochondrial introgression at secondary contacts. This study demonstrates that climate change can impact sexes with different dispersal biology in different ways. Incongruence between population and mitochondrial trees calls for a genome-wide investigation into dispersal, mitochondrial introgression and mitonuclear evolution.
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41
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Bouchard C, Tessier N, Lapointe FJ. Watersheds influence the wood turtle’s (Glyptemys insculpta) genetic structure. CONSERV GENET 2019. [DOI: 10.1007/s10592-019-01169-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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42
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Lalonde MML, Marcus JM. Entomological time travel: reconstructing the invasion history of the buckeye butterflies (genus Junonia) from Florida, USA. Biol Invasions 2019. [DOI: 10.1007/s10530-019-01948-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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43
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Manuzzi A, Zane L, Muñoz-Merida A, Griffiths AM, Veríssimo A. Population genomics and phylogeography of a benthic coastal shark (Scyliorhinus canicula) using 2b-RAD single nucleotide polymorphisms. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly185] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Alice Manuzzi
- CIBIO – U.P. – Research Center for Biodiversity and Genetic Resources, Vairão, Portugal
- National Institute of Aquatic Resources, Technical University of Denmark, Vejlsøvej, Silkeborg, Denmark
| | - Lorenzo Zane
- Department of Biology, University of Padova, Padova, Italy
- Consorzio Nazionale Interuniversitario per le Scienze del Mare (CoNISMa), Roma, Italy
| | - Antonio Muñoz-Merida
- CIBIO – U.P. – Research Center for Biodiversity and Genetic Resources, Vairão, Portugal
| | | | - Ana Veríssimo
- CIBIO – U.P. – Research Center for Biodiversity and Genetic Resources, Vairão, Portugal
- Virginia Institute of Marine Science, College of William and Mary, VA, USA
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44
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Genetic source–sink dynamics among naturally structured and anthropogenically fragmented puma populations. CONSERV GENET 2018. [DOI: 10.1007/s10592-018-1125-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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45
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Aylward CM, Murdoch JD, Kilpatrick CW. Genetic legacies of translocation and relictual populations of American marten at the southeastern margin of their distribution. CONSERV GENET 2018. [DOI: 10.1007/s10592-018-1130-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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46
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Aleixo-Pais I, Salmona J, Sgarlata GM, Rakotonanahary A, Sousa AP, Parreira B, Kun-Rodrigues C, Ralantoharijaona T, Jan F, Rasolondraibe E, Minhós T, Zaonarivelo JR, Andriaholinirina NV, Chikhi L. The genetic structure of a mouse lemur living in a fragmented habitat in Northern Madagascar. CONSERV GENET 2018. [DOI: 10.1007/s10592-018-1126-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Binks RM, Byrne M, McMahon K, Pitt G, Murray K, Evans RD. Habitat discontinuities form strong barriers to gene flow among mangrove populations, despite the capacity for long-distance dispersal. DIVERS DISTRIB 2018. [DOI: 10.1111/ddi.12851] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- Rachel M. Binks
- Biodiversity and Conservation Science; Department of Biodiversity, Conservation and Attractions; Kensington Western Australia Australia
| | - Margaret Byrne
- Biodiversity and Conservation Science; Department of Biodiversity, Conservation and Attractions; Kensington Western Australia Australia
| | - Kathryn McMahon
- School of Sciences and Centre for Marine Ecosystems Research; Edith Cowan University; Joondalup Western Australia Australia
| | - Georgina Pitt
- Biodiversity and Conservation Science; Department of Biodiversity, Conservation and Attractions; Kensington Western Australia Australia
| | - Kathy Murray
- Biodiversity and Conservation Science; Department of Biodiversity, Conservation and Attractions; Kensington Western Australia Australia
| | - Richard D. Evans
- Biodiversity and Conservation Science; Department of Biodiversity, Conservation and Attractions; Kensington Western Australia Australia
- School of Biological Sciences and Oceans Institute; University of Western Australia; Crawley Western Australia Australia
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48
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Bertl J, Ringbauer H, Blum MG. Can secondary contact following range expansion be distinguished from barriers to gene flow? PeerJ 2018; 6:e5325. [PMID: 30294507 PMCID: PMC6171497 DOI: 10.7717/peerj.5325] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 07/01/2018] [Indexed: 11/20/2022] Open
Abstract
Secondary contact is the reestablishment of gene flow between sister populations that have diverged. For instance, at the end of the Quaternary glaciations in Europe, secondary contact occurred during the northward expansion of the populations which had found refugia in the southern peninsulas. With the advent of multi-locus markers, secondary contact can be investigated using various molecular signatures including gradients of allele frequency, admixture clines, and local increase of genetic differentiation. We use coalescent simulations to investigate if molecular data provide enough information to distinguish between secondary contact following range expansion and an alternative evolutionary scenario consisting of a barrier to gene flow in an isolation-by-distance model. We find that an excess of linkage disequilibrium and of genetic diversity at the suture zone is a unique signature of secondary contact. We also find that the directionality index ψ, which was proposed to study range expansion, is informative to distinguish between the two hypotheses. However, although evidence for secondary contact is usually conveyed by statistics related to admixture coefficients, we find that they can be confounded by isolation-by-distance. We recommend to account for the spatial repartition of individuals when investigating secondary contact in order to better reflect the complex spatio-temporal evolution of populations and species.
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Affiliation(s)
- Johanna Bertl
- Department of Molecular Medicine, Aarhus University, Aarhus, Denmark
- Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna, Austria
| | - Harald Ringbauer
- Department of Human Genetics, University of Chicago, Chicago, IL, USA
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Michael G.B. Blum
- Laboratoire TIMC-IMAG, UMR 5525, Université Grenoble Alpes, CNRS, Grenoble, France
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49
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Bisconti R, Porretta D, Arduino P, Nascetti G, Canestrelli D. Hybridization and extensive mitochondrial introgression among fire salamanders in peninsular Italy. Sci Rep 2018; 8:13187. [PMID: 30181603 PMCID: PMC6123427 DOI: 10.1038/s41598-018-31535-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 08/08/2018] [Indexed: 01/17/2023] Open
Abstract
Discordance between mitochondrial and nuclear patterns of population genetic structure is providing key insights into the eco-evolutionary dynamics between and within species, and their assessment is highly relevant to biodiversity monitoring practices based on DNA barcoding approaches. Here, we investigate the population genetic structure of the fire salamander Salamandra salamandra in peninsular Italy. Both mitochondrial and nuclear markers clearly identified two main population groups. However, nuclear and mitochondrial zones of geographic transition between groups were located 600 km from one another. Recent population declines in central Italy partially erased the genetic imprints of past hybridization dynamics. However, the overall pattern of genetic variation, together with morphological and fossil data, suggest that a rampant mitochondrial introgression triggered the observed mitonuclear discordance, following a post-glacial secondary contact between lineages. Our results clearly show the major role played by reticulate evolution in shaping the structure of Salamandra salamandra populations and, together with similar findings in other regions of the species' range, contribute to identify the fire salamander as a particularly intriguing case to investigate the complexity of mechanisms triggering patterns of mitonuclear discordance in animals.
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Affiliation(s)
- Roberta Bisconti
- Tuscia University, Department of Ecological and Biological Sciences, Viterbo, 01100, Italy.
| | - Daniele Porretta
- University of Rome, "Sapienza", Department of Environmental Biology, Rome, 00185, Italy
| | - Paola Arduino
- Tuscia University, Department of Ecological and Biological Sciences, Viterbo, 01100, Italy
| | - Giuseppe Nascetti
- Tuscia University, Department of Ecological and Biological Sciences, Viterbo, 01100, Italy
| | - Daniele Canestrelli
- Tuscia University, Department of Ecological and Biological Sciences, Viterbo, 01100, Italy
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50
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Farris E, Filigheddu R, Mameli G, Falanga V, Vanetti I, Rosati L, Binelli G. Is population genetic structure of vascular plants shaped more by ecological or geographic factors? A study case on the Mediterranean endemic Centaurea filiformis (Asteraceae). PLANT BIOLOGY (STUTTGART, GERMANY) 2018; 20:936-947. [PMID: 29873892 DOI: 10.1111/plb.12853] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 06/01/2018] [Indexed: 06/08/2023]
Abstract
All known populations of the Sardinian endemic Centaurea filiformis Viv. (Asteraceae) were studied in order to understand the impact of both geographic and ecological factors on the genetic structuring of this species. Fourteen populations and 234 individuals were sampled. The demographic structure of the populations and the reproductive ecology were estimated in 28 plots. Population genetic analyses were based on SSR markers. Genetic structure was investigated by spatial Bayesian methods. Average densities of 0.51 individuals m-2 were detected, with a prevalence of adults. Ten species of pollinators were identified; C. filiformis ability to self-pollinate and myrmecochory were demonstrated experimentally. The populations displayed an average heterozygosity value of He = 0.576 and high genetic differentiation (overall FST = 0.218). Bayesian analysis suggests that five is the most probable number of gene pools of origin. A strong correlation between geographic distances and genetic distances among populations was highlighted. The demographic population structure of C. filiformis is dominated by adults, suggesting that it is a stable-regressive or senile species, investing more in local persistence than colonisation ability. Despite the scattered distribution, the populations studied do not present evidence of genetic erosion. The analysis of genetic differentiation reveals very high differentiation levels among populations, thus indicating that effective barriers exist against gene flow. A general conclusion is that population distribution results in a clear genetic structure for the populations studied, and that geography and not ecology is shaping the present distribution of this species.
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Affiliation(s)
- E Farris
- Department of Chemistry and Pharmacy, University of Sassari, Sassari, Italy
| | - R Filigheddu
- Department of Chemistry and Pharmacy, University of Sassari, Sassari, Italy
| | - G Mameli
- Department of Chemistry and Pharmacy, University of Sassari, Sassari, Italy
| | - V Falanga
- Dipartimento di Biotecnologie e Scienze della Vita, Università dell'Insubria, Varese, Italy
| | - I Vanetti
- Dipartimento di Biotecnologie e Scienze della Vita, Università dell'Insubria, Varese, Italy
| | - L Rosati
- School of Agricultural, Forestry, Food and Environmental Sciences, University of Basilicata, Potenza, Italy
| | - G Binelli
- Dipartimento di Biotecnologie e Scienze della Vita, Università dell'Insubria, Varese, Italy
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