scholarly journals Polyphyletic ancestry of expanding Patagonian Chinook salmon populations

2016 ◽  
Author(s):  
Cristian Correa ◽  
Paul Moran
Keyword(s):  
Genetic Diversity ◽  
North America ◽  
Mixture Models ◽  
Chinook Salmon ◽  
Future Research ◽  
Potential Donor ◽  
Genetic Lineages ◽  
The North ◽  
Introduced Range ◽  
Lineage Admixture

AbstractChinook salmon native to North America are spreading through South America’s Patagonia and have become the most widespread anadromous salmon invasion ever documented. To better understand the colonization history and role that genetic diversity might have played in the founding and radiation of these new populations, we characterized ancestry and genetic diversity across latitude (39-48°S). Samples from four distant basins in Chile were genotyped for 13 microsatellite loci, and allocated, through probabilistic mixture models, to 148 potential donor populations in North America representing 46 distinct genetic lineages. Patagonian Chinook salmon clearly had a diverse and heterogeneous ancestry. Lineages from the Lower Columbia River were introduced for salmon open-ocean ranching in the late 1970s and 1980s, and were prevalent south of 43°S. In the north, however, a diverse assembly of lineages was found, associated with net-pen aquaculture during the 1990s. Finally, we showed that possible lineage admixture in the introduced range can confound allocations inferred from mixture models, a caveat previously overlooked in studies of this kind. While we documented high genetic and lineage diversity in expanding Patagonian populations, the degree to which diversity drives adaptive potential remains unclear. Our new understanding of diversity across latitude will guide future research.

Geographic Patterns of Interspecific Hybridization between Spotted Knapweed (Centaurea stoebe) and Diffuse Knapweed (C. diffusa)

2009 ◽  
Vol 2 (1) ◽  
pp. 55-69 ◽  
Author(s):  
Amy C. Blair ◽  
Ruth A. Hufbauer
Keyword(s):  
North America ◽  
North American ◽  
Management Strategies ◽  
Spotted Knapweed ◽  
The North ◽  
Hybrid Swarms ◽  
Hybrid Plants ◽  
Introduced Range ◽  
Diffuse Knapweed ◽  
A Site

AbstractHybridization between species has the potential to change invasion dynamics. Field observations suggest that spotted knapweed and diffuse knapweed, two ecologically and economically destructive invasive plants, hybridize in their introduced range. As a first step towards understanding whether hybridization has affected the dynamics of the invasion of these species, we conducted field surveys in the introduced (North American) and native (European) ranges to discern patterns of hybridization and measured fitness-related traits among field hybrids and parental species. In North America we detected plants with hybrid morphology in 97% of the diffuse knapweed sites (n= 40); such hybrid plants were taller and more often exhibited polycarpy than plants with typical diffuse knapweed morphology. Hybrids were not detected in North American spotted knapweed sites (n= 22). In most regions surveyed in Europe, diffuse knapweed and spotted knapweed were isolated from each other and existed as distinct, nonhybridizing species. However, in Ukraine, the two species frequently coexisted within a site, resulting in hybrid swarms. On average, the plants from the North American diffuse knapweed sites (including plants with both diffuse and hybrid morphology), were larger than the apparently pure diffuse knapweed in the native range. The cross-continental patterns of hybridization likely are explained by differences in cytology. It recently has been confirmed that the spotted knapweed in North America is tetraploid whereas the diffuse knapweed is diploid. Genetic incompatibilities associated with these two cytotypes likely prevent ongoing hybridization. We hypothesize that hybrid individuals were introduced to North America along with diffuse knapweed. Because plants with hybrid morphology are found in nearly all North American diffuse knapweed sites, the introduction of hybrids likely occurred early in the invasion of diffuse knapweed. Thus, although the presence of hybrids might facilitate the ongoing invasion of diffuse knapweed into North America, elevated concern regarding their presence might not be warranted. Because such individuals are not likely to represent a new hybridization event, currently effective management strategies used in diffuse knapweed sites should not need alteration.

scholarly journals Phylogenetics of a Fungal Invasion: Origins and Widespread Dispersal of White-Nose Syndrome

mBio ◽  
2017 ◽  
Vol 8 (6) ◽  
Author(s):  
Kevin P. Drees ◽  
Jeffrey M. Lorch ◽  
Sebastien J. Puechmaille ◽  
Katy L. Parise ◽  
Gudrun Wibbelt ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
North America ◽  
North American ◽  
Fungal Pathogen ◽  
Phylogenetic Study ◽  
Pseudogymnoascus Destructans ◽  
Long Distance ◽  
Recent Introduction ◽  
White Nose Syndrome ◽  
The North

ABSTRACT Globalization has facilitated the worldwide movement and introduction of pathogens, but epizoological reconstructions of these invasions are often hindered by limited sampling and insufficient genetic resolution among isolates. Pseudogymnoascus destructans , a fungal pathogen causing the epizootic of white-nose syndrome in North American bats, has exhibited few genetic polymorphisms in previous studies, presenting challenges for both epizoological tracking of the spread of this fungus and for determining its evolutionary history. We used single nucleotide polymorphisms (SNPs) from whole-genome sequencing and microsatellites to construct high-resolution phylogenies of P. destructans . Shallow genetic diversity and the lack of geographic structuring among North American isolates support a recent introduction followed by expansion via clonal reproduction across the epizootic zone. Moreover, the genetic relationships of isolates within North America suggest widespread mixing and long-distance movement of the fungus. Genetic diversity among isolates of P. destructans from Europe was substantially higher than in those from North America. However, genetic distance between the North American isolates and any given European isolate was similar to the distance between the individual European isolates. In contrast, the isolates we examined from Asia were highly divergent from both European and North American isolates. Although the definitive source for introduction of the North American population has not been conclusively identified, our data support the origin of the North American invasion by P. destructans from Europe rather than Asia. IMPORTANCE This phylogenetic study of the bat white-nose syndrome agent, P. destructans , uses genomics to elucidate evolutionary relationships among populations of the fungal pathogen to understand the epizoology of this biological invasion. We analyze hypervariable and abundant genetic characters (microsatellites and genomic SNPs, respectively) to reveal previously uncharacterized diversity among populations of the pathogen from North America and Eurasia. We present new evidence supporting recent introduction of the fungus to North America from a diverse Eurasian population, with limited increase in genetic variation in North America since that introduction.

Molecular genetic diversity of the French-American grapevine hybrids cultivated in North America

Genome ◽  
2003 ◽  
Vol 46 (6) ◽  
pp. 1037-1048 ◽  
Author(s):  
Patrick Pollefeys ◽  
Jean Bousquet
Keyword(s):  
Genetic Diversity ◽  
North America ◽  
Genetic Background ◽  
Molecular Genetic ◽  
Group Method ◽  
Dna Profile ◽  
Vitis Riparia ◽  
The North ◽  
Pair Group ◽  
Molecular Genetic Diversity

French-American hybrid grapevines are most popular in eastern and mid-western North America: they are hardy cultivars derived from crosses between the European Vitis vinifera and American wild vines. The aim of this study was to characterize their genetic background using 6 microsatellite (SSR) markers and a set of 33 diagnostic RAPD markers. The latter were reproducible with different PCR thermal cyclers. Two SSR loci were found to be synonymous, VrZAG47 and VVMD27. The DNA profile frequencies estimated for each cultivar were much lower with multi-locus SSR data than that obtained from multi-fragment RAPD data. There was no significant correlation between the multi-locus DNA profile frequencies derived from SSRs and those from RAPDs. Estimates of genetic diversity derived from SSRs were generally higher and the average similarity between cultivars was generally lower than values reported for subgroups of V. vinifera, in accordance with expectations for hybrid cultivars. The phenetic relationships depicted by UPGMA (unweighted pair-group method with arithmetic averaging) and neighbor-joining analyses of microsatellite data were congruent and, to a large extent, in agreement with the known pedigree or history of each cultivar. A major dichotomy was observed between one group where the known genetic background was dominated by the North American Vitis riparia and Vitis labrusca, and another one where the genetic background was dominated by the European V. vinifera. Two Kulhmann varieties thought to be synonymous were found to be different, though closely related.Key words: French-American hybrids, genetic diversity, RAPD, SSR, Vitis.

scholarly journals Strong Genetic Differentiation Between North American and European Populations of Phytophthora alni subsp. uniformis

2013 ◽  
Vol 103 (2) ◽  
pp. 190-199 ◽  
Author(s):  
Jaime Aguayo ◽  
Gerard C. Adams ◽  
Fabien Halkett ◽  
Mursel Catal ◽  
Claude Husson ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
North America ◽  
Mating System ◽  
North American ◽  
Parental Species ◽  
European Countries ◽  
North American Population ◽  
Natural Ecosystems ◽  
Reproduction Mode ◽  
The North

Alder decline caused by Phytophthora alni has been one of the most important diseases of natural ecosystems in Europe during the last 20 years. The emergence of P. alni subsp. alni —the pathogen responsible for the epidemic—is linked to an interspecific hybridization event between two parental species: P. alni subsp. multiformis and P. alni subsp. uniformis. One of the parental species, P. alni subsp. uniformis, has been isolated in several European countries and, recently, in North America. The objective of this work was to assess the level of genetic diversity, the population genetic structure, and the putative reproduction mode and mating system of P. alni subsp. uniformis. Five new polymorphic microsatellite markers were used to contrast both geographical populations. The study comprised 71 isolates of P. alni subsp. uniformis collected from eight European countries and 10 locations in North America. Our results revealed strong differences between continental populations (Fst = 0.88; Rst = 0.74), with no evidence for gene flow. European isolates showed extremely low genetic diversity compared with the North American collection. Selfing appears to be the predominant mating system in both continental collections. The results suggest that the European P. alni subsp. uniformis population is most likely alien and derives from the introduction of a few individuals, whereas the North American population probably is an indigenous population.

scholarly journals Genetic diversity of rhizobia nodulating Trifolium ambiguum in North America

2001 ◽  
Vol 47 (1) ◽  
pp. 81-85 ◽  
Author(s):  
P Seguin ◽  
P H Graham ◽  
C C Sheaffer ◽  
N J Ehlke ◽  
M P Russelle
Keyword(s):  
Genetic Diversity ◽  
North America ◽  
North American ◽  
Diversity Index ◽  
Diversity Indices ◽  
Clustering Methods ◽  
Center Of Origin ◽  
Trifolium Ambiguum ◽  
Kura Clover ◽  
The North

Kura clover (Trifolium ambiguum M.B.) is a persistent rhizomatous forage legume, whose use in the U.S.A. is limited by establishment difficulties in part attributable to nodulation problems. In this study, soil was collected from established stands of Kura clover growing in 9 diverse North American environments. Rhizobia were plant-trapped using Kura clover cv. Endura as host, then rhizobia from nodules fingerprinted using BOX-PCR. The diversity of isolates from North America was then contrasted to that of rhizobia from a single Caucasian environment (Russia), the center of origin for this species. Populations were characterized using clustering methods, and genetic diversity estimated using the Shannon-Weaver diversity index. The genetic diversity of the North American populations was extremely limited, all isolates being closely related to two of the strains found in a locally available commercial inoculant. In contrast, Russian isolates formed a distinct cluster with significant internal genetic diversity. Genetic diversity indices for the North American and Russian populations were 3.5 and 10.76, respectively. The implication of this and other studies is that Kura clover is highly specific in Rhizobium requirement. If the performance of this legume in the U.S.A. is to be improved, either by modifying current establishment practices or plant breeding, it is essential that these studies be paralleled by more collections and evaluation of rhizobia from its center of origin, given the extremely limited diversity of rhizobia found in North America.Key words: genetic diversity, rhizobia, Kura clover, BOX-PCR.

scholarly journals Hybridization and range expansion in tamarisk beetles (Diorhabda spp.) introduced to North America for classical biological control

2021 ◽  
Author(s):  
Amanda R Stahlke ◽  
Ellyn V. Bitume ◽  
A. Zeynep Ozsoy ◽  
Dan W. Bean ◽  
Anne Veillet ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Biological Control ◽  
North America ◽  
Range Expansion ◽  
De Novo ◽  
Classical Biological Control ◽  
Genomic Variation ◽  
Biocontrol Agents ◽  
Introduced Range ◽  
Tamarix Spp

With the global rise of human-mediated translocations and invasions, it is critical to understand the genomic consequences of hybridization and mechanisms of range expansion. Conventional wisdom is that high genetic drift and loss of genetic diversity due to repeated founder effects will constrain introduced species. However, reduced genetic variation can be countered by behavioral aspects and admixture with other distinct populations. As planned invasions, classical biological control (biocontrol) agents present important opportunities to understand the mechanisms of establishment and spread in a novel environment. The ability of biocontrol agents to spread and adapt, and their effects on local ecosystems, depends on genomic variation and the consequences of admixture in novel environments. Here we use a biocontrol system to examine the genome-wide outcomes of introduction, spread, and hybridization in four cryptic species of a biocontrol agent, the tamarisk beetle (Diorhabda carinata, D. carinulata, D. elongata, and D. sublineata), introduced from six localities across Eurasia to control the invasive shrub tamarisk (Tamarix spp.) in western North America. We assembled a de novo draft reference genome and applied RADseq to over 500 individuals from laboratory cultures, the native ranges, and across the introduced range. Despite evidence of a substantial genetic bottleneck among D. carinulata in N. America, populations continue to establish and spread, possibly due to aggregation behavior. We found that D. carinata, D. elongata, and D. sublineata hybridize in the field to varying extents, with D. carinata x D. sublineata hybrids being the most abundant. Genetic diversity was greater at sites with hybrids, highlighting potential for increased ability to adapt and expand. Our results demonstrate the complex patterns of genomic variation that can result from introduction of multiple ecotypes or species for biocontrol, and the importance of understanding them to predict and manage the effects of biocontrol agents in novel ecosystems.

scholarly journals Phylogeny of North American Powassan virus

2001 ◽  
Vol 82 (7) ◽  
pp. 1657-1665 ◽  
Author(s):  
Gregory D. Ebel ◽  
Andrew Spielman ◽  
Sam R. Telford
Keyword(s):  
Genetic Diversity ◽  
New York ◽  
Amino Acid ◽  
North America ◽  
Adaptive Evolution ◽  
Envelope Protein ◽  
Amino Acid Sequences ◽  
Ixodid Ticks ◽  
Genetic Lineages ◽  
Powassan Virus

To determine whether Powassan virus (POW) and deer tick virus (DTV) constitute distinct flaviviral populations transmitted by ixodid ticks in North America, we analysed diverse nucleotide sequences from 16 strains of these viruses. Two distinct genetic lineages are evident, which may be defined by geographical and host associations. The nucleotide and amino acid sequences of lineage one (comprising New York and Canadian POW isolates) are highly conserved across time and space, but those of lineage two (comprising isolates from deer ticks and a fox) are more variable. The divergence between lineages is much greater than the variation within either lineage, and lineage two appears to be more diverse genetically than is lineage one. Application of McDonald–Kreitman tests to the sequences of these strains indicates that adaptive evolution of the envelope protein separates lineage one from lineage two. The two POW lineages circulating in North America possess a pattern of genetic diversity suggesting that they comprise distinct subtypes that may perpetuate in separate enzootic cycles.

scholarly journals On the frequency of northern and mountain genetic variants of widespread species: essential biodiversity information in a warmer world

2019 ◽  
Vol 191 (4) ◽  
pp. 440-474 ◽  
Author(s):  
Lars Hedenäs
Keyword(s):  
Genetic Diversity ◽  
Genetic Variants ◽  
Climate Models ◽  
Biodiversity Loss ◽  
Genetic Composition ◽  
Widespread Species ◽  
Moss Species ◽  
Genetic Lineages ◽  
The North ◽  
Or Groups

Abstract Biodiversity studies and conservation management often neglect fundamental genetic diversity, even if biodiversity loss due to reduction in genetic diversity in declining, relatively common species is probably greater than the loss resulting from disappearing rare species. Climate models suggest that global warming will especially affect high latitudes due to a higher than average temperature increase towards the poles. In widespread Northern Hemisphere species, climate warming will therefore negatively affect especially northern and mountain genetic variants (NMGVs) in the same way that it will affect species with similar distributions. To explore whether NMGVs are frequent, they were searched for in ten widespread moss species based on a wide geographical sampling in Sweden and (two-) three (-four) molecular markers per species. NeighborNet split networks and jackknife analyses showed that eight of the studied species include one or more northern or, in most cases, mountain intraspecific genetic lineages or groups of related haplotypes. Analysis of molecular variance also showed that in the two species lacking such lineages or groups the genetic composition differs between different parts of Sweden or between lowlands and mountains of the north. Haplotype or nucleotide diversity is often higher in the north or mountains than in the south or lowlands. The high incidence of NMGVs, differences in genetic composition between the study regions and the frequent high diversity in the north or mountains show that conservation of the total biodiversity must also include the genetic diversity, not just the more obvious species-level taxa with restricted northern or mountain distributions.

scholarly journals Genetic diversification in the East Himalayas as revealed by comparative phylogeography of the black-throated bushtit and Elliot’s laughing thrush

2015 ◽  
Vol 61 (5) ◽  
pp. 935-942 ◽  
Author(s):  
Qing Quan ◽  
Yanhua Qu ◽  
Fumin Lei
Keyword(s):  
Genetic Diversity ◽  
Ecological Niche Modeling ◽  
Glacial Cycles ◽  
Comparative Phylogeography ◽  
High Genetic Diversity ◽  
Climatic Fluctuations ◽  
Genetic Lineages ◽  
The North ◽  
Suitable Habitats ◽  
Glacial Periods

Abstract The Southwest Mountainous region of the eastern Himalayas is a hotspot with extraordinarily high biodiversity and endemism, but the processes that have driven this unique diversity are largely unknown. We evaluated processes that have contributed to the current observed high genetic diversity in this region by integrating comparative phylogeography with ecological niche modeling in a study of two representative birds of the Southwest Mountains: the black-throated bushtit Aegithalos concinnus and the Elliot’s laughing thrush Garrulax elliotii. Mitochondrial DNA analyses revealed multiple divergent genetic lineages, which are roughly congruent with the north, south and east eco-subregion division of the Southwest Mountains. This strong geographical structure in these two species suggests that lineage diversification has proceeded in situ between the eco-subregions of the Southwest Mountains. During Pleistocene glaciations, the two species responded differently to climatic fluctuations. A. con-cinnus maintained rather stable habitats, mostly evergreen forests, during glacial cycles and thus kept a stable population size and further accumulated genetic diversity. In contrast, G. elliotii, which is mostly active in shrublands, has shifted its suitable habitats with glacial cycles. This species dispersed to low elevation areas during glacial periods, which provided multiple opportunities for gene admixture. The admixture causes the mixing of previously isolated genetic lineages and thus obscures the pattern of genetic variation.

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