Abstract Detail

Bryophytes and Lichens on the Edges of Changing Ecosystems

Imwattana, Karn [1], Shaw, Jonathan [1].

Genetic structure of circumboreal peatmosses within the Sphagnum capillifolium complex (Bryophyta: Sphagnaceae).

How geographical features, long distance dispersal, and historical events shape population structure within species is an important question in biogeography. Peatmosses (Sphagnum) are semiaquatic to terrestrial plants mostly found in peatlands in temperate and boreal areas. Many Sphagnum species have circumboreal distributions, occurring across all continents of the Northern Hemisphere. Earlier work has shown that individuals of many circumboreal Sphagnum species are not panmictic, but exhibit population structure, with the most common pattern being one population covering eastern North America and Europe (amphi-Atlantic) and another population covering western North America, Siberia, and Asia (amphi-Pacific). In this work, genome-scale RAD-seq data were used to investigate the population structure of five closely related circumboreal species within the S. capillifolium complex: S. capillifolium, S. fuscum, S. quinquefarium, S. rubellum, and S. warnstorfii. In all of the five species, plants in eastern North America and Europe form one amphi-Atlantic population system. Within amphi-Atlantic populations, phylogenetic analyses indicate that European plants are typically nested within plants from eastern North America. Population structure in the amphi-Pacific region varied among the species but were often complex, with patterns of genetic admixture among distinct genotype groups evident in some areas. Patterns of population structure suggested that plants of each species survived in multiple refugia during the last glacial maximum (LGM), possibly one in eastern North America and another in the Beringia. The presence of admixed individuals suggests the possibility of gene flow between genetically differentiated populations. The locations of admixed individuals are mostly where populations meet or overlap, suggesting that admixture resulted from secondary contact.  These genetic results indicate the important role of historical events, especially Pleistocene glaciation, in shaping the complex population structure of plants with such broad distribution ranges.

1 - Duke University, Department of Biology, Box 90338, Durham, NC, 27708, USA

glacial refugia.

Presentation Type: Colloquium Presentations
Number: C7002
Abstract ID:295
Candidate for Awards:A. J. Sharp Award

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