Dataset Information

Evolutionary dynamics of mixed-ploidy populations in an annual herb: dispersal, local persistence and recurrent origins of polyploids.

ABSTRACT:

Background and aims

Despite the recent wealth of studies targeted at contact zones of cytotypes in various species, some aspects of polyploid evolution are still poorly understood. This is especially the case for the frequency and success rate of spontaneous neopolyploidization or the temporal dynamics of ploidy coexistence, requiring massive ploidy screening and repeated observations, respectively. To fill this gap, an extensive study of spatio-temporal patterns of ploidy coexistence was initiated in the widespread annual weed Tripleurospermum inodorum (Asteraceae).

Methods

DNA flow cytometry along with confirmatory chromosome counts was employed to assess ploidy levels of 11?018 adult individuals and 1263 ex situ germinated seedlings from 1209 Central European populations. The ploidy screening was conducted across three spatial scales and supplemented with observations of temporal development of 37 mixed-ploidy populations.

Key results

The contact zone between the diploid and tetraploid cytotypes has a diffuse, mosaic-like structure enabling common cytotype coexistence from the within-population to the landscape level. A marked difference in monoploid genome size between the two cytotypes enabled the easy distinction of neotetraploid mutants from long-established tetraploids. Neotetraploids were extremely rare (0·03?%) and occurred solitarily. Altogether five ploidy levels (2 x -6 x ) and several aneuploids were discovered; the diversity in nuclear DNA content was highest in early ontogenetic stages (seedlings) and among individuals from mixed-ploidy populations. In spite of profound temporal oscillations in cytotype frequencies in mixed-ploidy populations, both diploids and tetraploids usually persisted up to the last census.

Conclusions

Diploids and tetraploids commonly coexist at all spatial scales and exhibit considerable temporal stability in local ploidy mixtures. Mixed-ploidy populations containing fertile triploid hybrids probaby act as effective generators of cytogenetic novelty and may facilitate inter-ploidy gene flow. Neopolyploid mutants were incapable of local establishment.

SUBMITTER: Certner M

PROVIDER: S-EPMC5737363 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature

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Publications

Evolutionary dynamics of mixed-ploidy populations in an annual herb: dispersal, local persistence and recurrent origins of polyploids.

Certner Martin M Fenclová Eliška E Kúr Pavel P Kolár Filip F Koutecký Petr P Krahulcová Anna A Suda Jan J

Annals of botany 20170801 2

<h4>Background and aims</h4>Despite the recent wealth of studies targeted at contact zones of cytotypes in various species, some aspects of polyploid evolution are still poorly understood. This is especially the case for the frequency and success rate of spontaneous neopolyploidization or the temporal dynamics of ploidy coexistence, requiring massive ploidy screening and repeated observations, respectively. To fill this gap, an extensive study of spatio-temporal patterns of ploidy coexistence wa ...[more]

PMID: 28398545

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Project description:Background and aimsIsolated populations constitute an ideal laboratory to study the consequences of intraspecific divergence, because intrinsic incompatibilities are more likely to accumulate under reduced gene flow. Here, we use a widespread bromeliad with a patchy distribution, Pitcairnia lanuginosa, as a model to infer processes driving Neotropical diversification and, thus, to improve our understanding of the origin and evolutionary dynamics of biodiversity in this highly speciose region.MethodsWe assessed the timing of lineage divergence, genetic structural patterns and historical demography of P. lanuginosa, based on microsatellites, and plastid and nuclear sequence data sets using coalescent analyses and an Approximate Bayesian Computation framework. Additionally, we used species distribution models (SDMs) to independently estimate potential changes in habitat suitability.Key resultsDespite morphological uniformity, plastid and nuclear DNA data revealed two distinct P. lanuginosa lineages that probably diverged through dispersal from the Cerrado to the Central Andean Yungas, following the final uplift of the Andes, and passed through long-term isolation with no evidence of migration. Microsatellite data indicate low genetic diversity and high levels of inbreeding within populations, and restricted gene flow among populations, which are likely to be a consequence of bottlenecks (or founder events), and high selfing rates promoting population persistence in isolation. SDMs showed a slight expansion of the suitable range for P. lanuginosa lineages during the Last Glacial Maximum, although molecular data revealed a signature of older divergence. Pleistocene climatic oscillations thus seem to have played only a minor role in the diversification of P. lanuginosa, which probably persisted through adverse conditions in riparian forests.ConclusionsOur results imply drift as a major force shaping the evolution of P. lanuginosa, and suggest that dispersal events have a prominent role in connecting Neotropical open and forest biomes.

Dataset Information

Evolutionary dynamics of mixed-ploidy populations in an annual herb: dispersal, local persistence and recurrent origins of polyploids.

Background and aims

Methods

Key results

Conclusions

Publications

Evolutionary dynamics of mixed-ploidy populations in an annual herb: dispersal, local persistence and recurrent origins of polyploids.

Similar Datasets

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