The Apogamous Life Cycle of Trichomanes Pinnatum—a Confirmation of Klekowski's Predictions on Homoeologous Pairing

Bierhorst, David W.

doi:10.1002/j.1537-2197.1975.tb14069.x

Cited by 12 publications

(5 citation statements)

References 17 publications

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“…Furthermore, because all parent sporophytes yielded progeny that segregated for at least one enzyme locus, they must have been generated by mating between two genetically different gametophytes (intergametophytic mating) (6). Recombinant genotypes were therefore produced in the sample populations by outcrossing (1,3,4,7,27) and not via homoeologous pairing (5,9). Thus, a single haploid spore cannot give rise to a genetically heterogeneous population of this colonizing species (9).…”

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confidence: 99%

Electrophoretic Evidence for Genetic Diploidy in the Bracken Fern ( Pteridium aquilinum )

Wolf

Haufler

Sheffield

1987

Science

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Analysis of isozyme variability demonstrates that bracken fern (Pteridium aquilinum) has a diploid genetic system and expresses solely disomic inheritance patterns. Electrophoretic data indicate that genetically variable progeny are produced in natural populations after intergametophytic mating rather than by a process involving recombination between duplicated unlinked loci. Although some enzymes are encoded by more than one locus, this has resulted from subcellular compartmentalization of isozymes, and there is no evidence of extensive gene duplication resulting from polyploidy. The conclusions reached in this report differ from those which propose polyploidy as an adaptive mechanism for maintaining genetic variability in Pteridium and other homosporous pteridophytes.

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confidence: 99%

Electrophoretic Evidence for Genetic Diploidy in the Bracken Fern ( Pteridium aquilinum )

Wolf

Haufler

Sheffield

1987

Science

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“…Remarkably, some of the best documented examples of homoeologous recombination in ferns come from studies of apomictic, or asexual, ferns. Several studies of chromosome pairing and/or segregation of isozyme and microsatellite markers demonstrate that some apomictic ferns produce gametophytes with novel, non‐parental genotypes that are best explained by homoeologous recombination ( Trichomanes pinnatum : Bierhorst, ; Dryopteris nipponensis : Ishikawa et al, ; Cyrtomium fortunei : Ootsuki et al, ). For example, Grusz () tested the hypothesis that homoeologous recombination is an important driver of genetic variation in apomictic ferns by following the segregation of eight microsatellite markers in natural populations of Myriopteris lindheimeri .…”

Section: Transcriptomic Genetic and Genomic Consequences Of Hybridimentioning

confidence: 99%

“…Similarily, Beck et al () used amplified fragment length polymorphism (AFLP) markers to infer a minimum of ten origins for the apomictic triploid Astrolepis integerrima under the assumption of genomic stasis in apomicts. While phylogenetic analysis of plastid sequence data provides strong evidence for five independently formed plastid lineages within A. integerrima (Beck et al, ), failure to considered the role of subsexual mechanisms such as homoeologous recombination for promoting genotype diversity within and among populations of apomictic species can lead to overestimation of independent origins (Bierhorst, ; Ishikawa et al, ; Ootsuki et al, ; Grusz, ).…”

Section: Multiple Origins Of Hybrid Fern Taxamentioning

confidence: 99%

Genetic and genomic aspects of hybridization in ferns

Sigel

2016

J of Sytematics Evolution

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The morphological and ecological intermediacy of hybrid taxa has long interested and challenged fern biologists, resulting in numerous systematic contributions focused on disentangling relationships within reticulate species complexes. From a genetic perspective, hybrid ferns are especially interesting because they represent the union of divergent parental genomes in unique evolutionary entities. This review summarizes advances in our knowledge of the genetic and genomic aspects of hybridization in ferns from the mid-20th century to the present. The different organismal products of hybridization, evolutionary aspects of additive and non-additive gene expression in allopolyploids, genetic and genomic mechanisms leading to gene silencing and loss, the roles of multiple origins and introgression for imparting genetic variation to hybrid fern taxa and their progenitors, and the utility of allopolyploid ferns to investigate mechanisms of genome evolution in the homosporous ferns are discussed. Comparisons are made to other plant lineages and important future research directions are highlighted, with the goal of stimulating additional research on hybrid ferns.

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“…Generally speaking, apomicts are assumed to produce genotypically clonal (i.e., identical) offspring (Hand & Koltunow, ; Verhoeven & Preite, ), but emerging research in ferns illustrates that these generalizations are not attributable to all apomictic groups. Following the suggestion of Klekowski () and preliminary evidence from Bierhorst () and Ishikawa et al (), recent studies have examined the extent to which apomictic polyploid ferns are able to produce genotypically variable offspring (Ootsuki et al, ; Grusz, ). These studies find evidence that, unlike with MFDR (Fig.…”

Section: Apomixis In Ferns Since 2004mentioning

confidence: 99%

A current perspective on apomixis in ferns

Grusz

2016

J of Sytematics Evolution

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This review provides a synopsis of apogamous reproduction in ferns and highlights important progress made in the study of fern apomixis over the past decade. First, a summary of the apomictic fern life cycle is provided, distinguishing between two pathways to diploid spore production that have been documented in apomictic ferns (premeiotic endomitosis and meiotic first division restitution) and briefly discussing the evolutionary implications of each. Next, recent trends in fern apomixis research are highlighted, exposing a shift in focus from the observation and characterization of apomixis in ferns to more integrated studies of the evolutionary and ecological implications of this reproductive mode. Peer-reviewed contributions from the past decade are then summarized, spanning the identification of new apomictic lineages through to the developmental, phylogenetic, and population genetic insights that have been made in studies of fern apomixis during that time. Gaps in our understanding of fern apomixis are also discussed, including the extent and implications of recombinant apomixis in ferns, the possible reversibility of reproductive mode (from apomictic to sexual) in ferns, and the genomic causes and consequences of apomixis in seed A u t h o r M a n u s c r i p t A u t h o r M a n u s c r i p t A u t h o r M a n u s c r i p tGrusz, 2 of 23 free vascular plants. Finally, future directions for fern apomixis research are discussed in the context of modern technological advances and recent insights from studies of apomixis in other groups.Keywords: apogamy, evolution of sex, meiosis, pteridophytes.A u t h o r M a n u s c r i p t A u t h o r M a n u s c r i p t A u t h o r M a n u s c r i p t Grusz, 3 of 23 "…apomixis is an escape from sterility, but it is an escape into a blind alley of evolution…" -Darlington, 1939A renaissance is underway in fern biology, propelled, in part, by technological advances being embraced by a growing research community. In particular, modern, cost-effective tools are enabling new inquiries into the unique fern life cycle, which alternates between independent, free-living sporophyte and gametophyte generations (Haufler et al., 2016). Among the many aspects of fern reproduction that are being examined in light of new approaches-and an improved understanding of fern evolution as a whole-is their propensity for apogamous reproduction (i.e., apomixis). This form of asexual reproduction (by spore or seed) is more common in ferns than in any other group of vascular plants. Nearly 10% of the ferns for which reproductive mode has been determined exhibit apomixis (Walker, 1985; Liu et al., 2012), compared to less than 1% in flowering plants (Bicknell & Koltunow, 2004; Becks & Alavi, 2015). Given that data on reproductive mode is lacking for the vast majority of ferns, this relative contribution of apomicts to fern diversity may well be an underestimate (Liu et al., 2012). The elevated frequency and distinctive meiotic characteristics of apomixis in ferns, which are elaborated upon bel...

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The Apogamous Life Cycle of Trichomanes Pinnatum—a Confirmation of Klekowski's Predictions on Homoeologous Pairing

Cited by 12 publications

References 17 publications

Electrophoretic Evidence for Genetic Diploidy in the Bracken Fern ( Pteridium aquilinum )

Electrophoretic Evidence for Genetic Diploidy in the Bracken Fern ( Pteridium aquilinum )

Genetic and genomic aspects of hybridization in ferns

A current perspective on apomixis in ferns

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