Partitioning and diversity of nuclear and organelle markers in native and introduced populations of<i>Epipactis helleborine</i>(Orchidaceae)

Squirrell, J.; Hollingsworth, Peter; Bateman, Richard M.; Dickson, J. H.; Light, Marilyn H. S.; MacConaill, M. A.; Tebbitt, Mark C.

doi:10.2307/3558447

Cited by 92 publications

(65 citation statements)

References 68 publications

(85 reference statements)

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“…Although long-distance colonization associated with biological invasion creates opportunities for founder effect, extreme reductions in genetic diversity seem the exception rather than the rule. Somewhat reduced diversity has been detected for some invasive plants (Barrett and Richardson 1986;Novak and Mack 1993;Neuffer and Hurka 1999;Meekins et al 2001), but not others (Brown and Marshall 1981;Warwick et al 1987;Consaul et al 1991;Squirrell et al 2001;Maron et al 2004). Severe reductions, as we observed for B. umbellatus, appear unusual.…”

Section: Discussionmentioning

confidence: 69%

Interaction Between Fournder Effect and Selection During Biological Invasion in an Aquatic Plant

Kliber

Eckert

2005

Evolution

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Abstract. Long-distance colonization and rapid range expansion associated with biological invasion may have major evolutionary consequences via both stochastic processes and selection. Using large-scale population genetic surveys, we demonstrate a major shift in the relative frequency of sexually fertile diploid versus sexually sterile triploid populations associated with the invasion of North America by a clonal aquatic plant, Butomus umbellatus. Most populations across the native European range were triploid (84% of 108), whereas most introduced populations were diploid (71% of 136). We evaluated the roles of stochastic processes versus natural selection in causing this shift by surveying predominantly neutral genetic variation at 28 RAPD loci. In Europe (EU) we detected 47 distinct genotypes among 142 plants sampled from 71 populations, whereas in North America (NA) we detected only six genotypes among 138 plants from 69 populations. Of the six NA genotypes, a set of four closely related genotypes were found only in triploid populations and a pair of closely related genotypes were found only in diploid populations, and these were genetically divergent from the triploid genotypes. This result is consistent with severe founder effect. Because sex creates genotypic variation and produces offspring with greater dispersal potential than those produced clonally, we tested the hypothesis that sexual reproduction characteristic of diploids has given them a colonization advantage that accounts for their high frequency in NA. However, we found little or no evidence of sexual recruitment in introduced diploids. One very widespread heterozygous genotype occurred in 95% of 38 introduced diploid populations (i.e., 72 of 76 plants surveyed) suggesting predominant clonal reproduction. Moreover genotypic diversity was not higher within or among diploid than triploid populations in either the native or introduced range. Low genetic diversity in diploid populations was also supported by a comparison of within-population quantitative variation for plant size under a common greenhouse environment. Thus, diploids have not been favored during colonization owing to their sexual fertility. However, concurrent studies have shown that NA diploids exhibit a much higher capacity for clonal reproduction, via small vegetative bulbils, than NA triploids, which almost never produce bulbils. The same difference in clonal capacity is not a consistent feature of the native EU populations. Taken together, these results suggest that strong founder effect has set the stage for a major increase in diploid frequency due to the particular, and possibly idiosyncratic, features of the diploid and triploid lineages introduced to North America.

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Section: Discussionmentioning

confidence: 69%

Interaction Between Fournder Effect and Selection During Biological Invasion in an Aquatic Plant

Kliber

Eckert

2005

Evolution

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“…If a high proportion of the total diversity in the native range is contained within individual populations (that is, low F ST ), founder effects will be mitigated even with a low number of colonizing individuals (for example, Epipactis helleborine, Squirrell et al, 2001). In its native range, G. carolinianum has higher allozyme genetic diversity and less genetic structure than expected when compared with similar species, with 80% of the total genetic variation residing within populations (Tables 1a and 3a).…”

Section: Discussionmentioning

confidence: 99%

Patterns of genetic diversity reveal multiple introductions and recurrent founder effects during range expansion in invasive populations of Geranium carolinianum (Geraniaceae)

et al. 2013

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Genetic diversity, and thus the adaptive potential of invasive populations, is largely based on three factors: patterns of genetic diversity in the species' native range, the number and location of introductions and the number of founding individuals per introduction. Specifically, reductions in genetic diversity ('founder effects') should be stronger for species with low withinpopulation diversity in their native range and few introductions of few individuals to the invasive range. We test these predictions with Geranium carolinianum, a winter annual herb native to North America and invasive in China. We measure the extent of founder effects using allozymes and microsatellites, and ask whether this is consistent with its colonization history and patterns of diversity in the native range. In the native range, genetic diversity is higher and structure is lower than expected based on life history traits. In China, our results provide evidence for multiple introductions near Nanjing, Jiangsu province, with subsequent range expansion to the west and south. Patterns of genetic diversity across China reveal weak founder effects that are driven largely by low-diversity populations at the expansion front, away from the introduction location. This suggests that reduced diversity in China has resulted from successive founder events during range expansion, and that the loss of genetic diversity in the Nanjing area was mitigated by multiple introductions from diverse source populations. This has implications for the future of G. carolinianum in China, as continued gene flow among populations should eventually increase genetic diversity within the more recently founded populations.

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“…We did not generate mass-spectroscopy data for these plants. The species were: E. dunensis (T. & T. A. Stephenson) Godfery (seven plants), an endemic inhabitant of Pinus-forested dunes in northwest England and Wales; E. gigantea Douglas ex Hooker (18 plants and one underground seedling), a native inhabitant of unshaded riparian areas, where it often grows adjacent to Alnus or Salix, in California and Oregon; and E. helleborine (29 plants, including one nonphotosynthetic individual), a native European forest species that is an introduced invasive in urban and native North American ectomycorrhizal forests (Squirrell et al 2001).…”

Section: (E) Molecular Analysismentioning

confidence: 99%

Changing partners in the dark: isotopic and molecular evidence of ectomycorrhizal liaisons between forest orchids and trees

Bidartondo

Burghardt

Gebauer

et al. 2004

Proc. R. Soc. Lond. B

380

487

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In the mycorrhizal symbiosis, plants exchange photosynthates for mineral nutrients acquired by fungi from the soil. This mutualistic arrangement has been subverted by hundreds of mycorrhizal plant species that lack the ability to photosynthesize. The most numerous examples of this behaviour are found in the largest plant family, the Orchidaceae. Although non-photosynthetic orchid species are known to be highly specialized exploiters of the ectomycorrhizal symbiosis, photosynthetic orchids are thought to use free-living saprophytic or pathogenic fungal lineages. However, we present evidence that putatively photosynthetic orchids from five species that grow in the understorey of forests (i) form mycorrhizas with ectomycorrhizal fungi of forest trees and (ii) have stable-isotope signatures indicating distinctive pathways for nitrogen and carbon acquisition approaching those of non-photosynthetic orchids that associate with ectomycorrhizal fungi of forest trees. These findings represent a major shift in our understanding of both orchid ecology and evolution because they explain how orchids can thrive in low-irradiance niches and they show that a shift to exploiting ectomycorrhizal fungi precedes viable losses of photosynthetic ability in orchid lineages.

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Partitioning and diversity of nuclear and organelle markers in native and introduced populations ofEpipactis helleborine(Orchidaceae)

Cited by 92 publications

References 68 publications

Interaction Between Fournder Effect and Selection During Biological Invasion in an Aquatic Plant

Interaction Between Fournder Effect and Selection During Biological Invasion in an Aquatic Plant

Patterns of genetic diversity reveal multiple introductions and recurrent founder effects during range expansion in invasive populations of Geranium carolinianum (Geraniaceae)

Changing partners in the dark: isotopic and molecular evidence of ectomycorrhizal liaisons between forest orchids and trees

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