Origin, taxonomy and population structure of the allopolyploid peat mossSphagnum majus

Såstad, Sigurd M.; Flatberg, Kjell Ivar; Hanssen, L.

doi:10.1007/bf00985459

Cited by 32 publications

(20 citation statements)

References 20 publications

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“…A possible explanation of the higher genetic diversity found in North American populations of S. affine compared to European populations may be that the species has not gone through severe bottlenecks during glaciations and subsequent recolonizations to the same extent as in Europe. Recently, Såstad et al. (2000) reported lower genetic diversity in North America compared to Europe in limited samples of Sphagnum majus (Russ.)…”

Section: Discussionsupporting

confidence: 91%

Population structure and genetic diversity of the amphiatlantic haploid peatmoss Sphagnum affine (Sphagnopsida)

Thingsgaard

2001

Heredity

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Nineteen populations of Sphagnum affine were included in a study of genetic diversity and structure in fragmented and less fragmented landscapes, and differentiation at intercontinental and three regional levels. Isozyme electrophoresis of eight enzyme systems revealed 12 variable loci, which could be used for haplotype identification. A hierachical analysis of variance (AMOVA) revealed no significant intercontinental differentiation, and very limited differentiation among European regions. A trend of decreasing diversity with increasing latitude was apparent. Gametic phase disequilibria was high, suggesting nonrandom mating and regionally high incidences of inbreeding. The partitioning of genetic variation within and among populations in each region varied among regions, the northernmost populations having 86% of the total variation among populations, the southernmost in Scandinavia having 25% of the variation among populations, whereas the American populations displayed 89% of the variation within populations. Fifteen alleles at eight loci occurred in the U.S.A. which were not encountered in Europe, whereas only three European alleles at one locus in three populations were not encountered in U.S.A. The differences in diversity between North America and Europe may result from loss of genetic diversity caused by founder effects during postglacial recolonization of northern Europe. In Europe, the main mountain ranges extend E-W, posing severe barriers to northwards migration of lowland species, compared to the N-S trend of mountain ranges in North America. The decline in genetic diversity and increase in population differentiation and gametic phase disequilibria towards the north in Scandinavia may be caused by a series of founder effects during postglacial migration. These may have corresponded to minor climatic oscillations that influenced the migration front/leading edge in the suboceanic lowlands of Norway. According to this model random genetic drift will be an increasingly important structuring factor with latitude.

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Section: Discussionsupporting

confidence: 91%

Population structure and genetic diversity of the amphiatlantic haploid peatmoss Sphagnum affine (Sphagnopsida)

Thingsgaard

2001

Heredity

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“…Earlier isozyme analyses rarely revealed genetic differentiation between conspecifi c populations on different continents, at least in temperate and boreal species. DNA-based markers have more frequently documented differentiation between intercontinentally disjunct populations S å stad et al, 2000 ;Sz ö v é nyi et al, 2008 ;Vanderpoorten et al, 2008 ). Few studies have tried to explicitly distinguish shared polymorphism that refl ects retention of ancestral variation from ongoing gene fl ow.…”

Section: Prospectusmentioning

confidence: 98%

Bryophyte diversity and evolution: Windows into the early evolution of land plants

Shaw

Szövényi

Shaw

2011

American J of Botany

192

136

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The "bryophytes" comprise three phyla of plants united by a similar haploid-dominant life cycle and unbranched sporophytes bearing one sporangium: the liverworts (Marchantiophyta), mosses (Bryophyta), and hornworts (Anthocerophyta). Combined, these groups include some 20000 species. As descendents of embryophytes that diverged before tracheophytes appeared, bryophytes offer unique windows into the early evolution of land plants. We review insights into the evolution of plant life cycles, in particular the elaboration of the sporophyte generation, the major lineages within bryophyte phyla, and reproductive processes that shape patterns of bryophyte evolution. Recent transcriptomic work suggests extensive overlap in gene expression in bryophyte sporophytes vs. gametophytes, but also novel patterns in the sporophyte, supporting Bower's antithetic hypothesis for origin of alternation of generations. Major lineages of liverworts, mosses, and hornworts have been resolved and general patterns of morphological evolution can now be inferred. The life cycles of bryophytes, arguably more similar to those of early embryophytes than are those in any other living plant group, provide unique insights into gametophyte mating patterns, sexual conflicts, and the efficacy and effects of spore dispersal during early land plant evolution.

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“…2006;Szövenyi ef al. 2008), reproducfive biology (Szövenyi et al 2009), and allopolyploidization (Cronberg 1996;Sâstad et al 1999Sâstad et al , 2000Sâstad et al , 2001Ricca and Shaw 2010) makes increased undersfanding of taxonomic/systematic relationships in the genus all fhe more important.…”

Section: Morphologieal Characterization-stem Leaf Variation Among Sammentioning

confidence: 96%

Systematics of the <I>Sphagnum fimbriatum</I> Complex: Phylogenetic Relationships, Morphological Variation, and Allopolyploidy

Shaw¹,

Flatberg²,

Szövényi³

et al. 2012

issn: 0363-6445

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The application of genetic tools for studying species delimitation and relationships in Sphagiutiit (peatmosses) has demonstrated that evolutionary patterns are complex and include homoploid hybridization and multiple taxa of allopolyploid origin. We investigated evolutionary relationships in the so-called S. fimbriatum complex and tested hypotheses of species delimitation derived from patterns of morphological variation, and determined the origin of one species with diploid gametophytes. Plastid DNA sequences resolve a single haplotype shared by one described species, S. coiicinnum, and a morphotype that we had hypothesÍ7,ed to be another species (referred to informally as S. "diskoense"). All samples of the polyploid, S. tescorwn, share an identical haplotype with most samples of S. ¡(ir¡^citsohiiii. Sphagnwii fimbriatum and S. girgaisolmii share several plastid DNA haplotypes, and also share haplotypes with two other morphotypes that we had hypothesized to be distinct species (S. "obscurum" and S. "ubertum"). Fixed or nearly fixed heterozygosity at ten microsatellite ICKÍ show that S. texorutii is an allopolyploid. Genetic admixture analyses and computation of hybrid indices from microsatellite data, in combination with sequences from the plastid genome, support the hypothesis that S. fimbriatum and S. girgvitstihnii are progenitors of S. /I'scor»»;, with S. girgensohnii as the maternal parent. Data from 14 microsatellite loci demonstrate that S. concinnum, S. fimbriatum, S. girgnisolmii, and S. tescorum are genetically distinct but the same data do not support separation of S. "diskoense," S. "obscurum," and S. "ubertum." Homoploid hybridization between S. fimbriatum and S. girgensohnii is strongly suggested by genetic data and phylogenetic analyses.

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Origin, taxonomy and population structure of the allopolyploid peat mossSphagnum majus

Cited by 32 publications

References 20 publications

Population structure and genetic diversity of the amphiatlantic haploid peatmoss Sphagnum affine (Sphagnopsida)

Population structure and genetic diversity of the amphiatlantic haploid peatmoss Sphagnum affine (Sphagnopsida)

Bryophyte diversity and evolution: Windows into the early evolution of land plants

Systematics of the <I>Sphagnum fimbriatum</I> Complex: Phylogenetic Relationships, Morphological Variation, and Allopolyploidy

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