Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Nov 16;12(11):e9489.
doi: 10.1002/ece3.9489. eCollection 2022 Nov.

Demographic history and gene flow in the peatmosses Sphagnum recurvum and Sphagnum flexuosum (Bryophyta: Sphagnaceae)

Karn Imwattana  1 , Blanka Aguero  1 , Aaron Duffy  1 , A Jonathan Shaw  1
Affiliations

Demographic history and gene flow in the peatmosses Sphagnum recurvum and Sphagnum flexuosum (Bryophyta: Sphagnaceae)

Karn Imwattana et al. Ecol Evol. .

Abstract

Population size changes and gene flow are processes that can have significant impacts on evolution. The aim of this study was to investigate the relationship of geography to patterns of gene flow and population size changes in a pair of closely related Sphagnum (peatmoss) species: S. recurvum and S. flexuosum. Both species occur in eastern North America, and S. flexuosum also occurs in Europe. Genetic data from restriction-site-associated DNA sequencing (RAD-seq) were used in this study. Analyses of gene flow were accomplished using coalescent simulations of site frequency spectra (SFSs). Signatures of gene flow were confirmed by f 4 statistics. For S. flexuosum, genetic diversity of plants in glaciated areas appeared to be lower than that in unglaciated areas, suggesting that glaciation can have an impact on effective population sizes. There is asymmetric gene flow from eastern North America to Europe, suggesting that Europe might have been colonized by plants from eastern North America after the last glacial maximum. The rate of gene flow between S. flexuosum and S. recurvum is lower than that between geographically disjunct S. flexuosum populations. The rate of gene flow between species is higher among sympatric plants of the two species than between currently allopatric S. flexuosum populations. There was also gene flow from S. recurvum to the ancestor S. flexuosum on both continents which occurred through secondary contact. These results illustrate a complex history of interspecific gene flow between S. flexuosum and S. recurvum, which occurred in at least two phases: between ancestral populations after secondary contact and between currently sympatric plants.

Keywords: demographic history; effective population size; gene flow; genetic diversity; glaciation; sphagnum.

PubMed Disclaimer

Figures

FIGURE 1
FIGURE 1
Field‐derived photographs of (a) Sphagnum flexuosum and (b) Sphagnum recurvum. Photos: Blanka Aguero (with permission).
FIGURE 2
FIGURE 2
Geographic locations of S. recurvum and S. flexuosum samples used in this study.
FIGURE 3
FIGURE 3
ABBA/BABA statistics analysis. The double‐headed arrows represent the putative introgression events, numbers of species trio are based on Table 3, and f 4 values represent the proportion of genome involved in introgression. Thick arrow is used for introgression events with f 4 higher than 0.01.
FIGURE 4
FIGURE 4
Best demographic model (“model 10 with secondary contact”). The width of the boxes is roughly proportional to the effective population sizes (Ne); the height of the boxes is roughly proportional to divergence time; arrows represent the presence and direction of gene flow; thick arrows is used when gene flow rate exceeds 0.01.
FIGURE 5
FIGURE 5
Variations in gene flow rates and effective population sizes of the best demographic model as inferred from parametric bootstrap.
FIGURE B1
FIGURE B1
Diagram showing variable names for the demographic parameters in Figures B2, B3, B4, B5 and Tables B1
FIGURE B2
FIGURE B2
Variations in effective population sizes (N) inferred from parametric bootstrap of the “full migration model” and “model 10”.
FIGURE B3
FIGURE B3
Variations in gene flow rates inferred from parametric bootstrap of the “full migration model” and “model 10”.
FIGURE B4
FIGURE B4
Variations in effective population sizes inferred from parametric bootstrap of the “full migration model with secondary contact” and “model 10 with secondary contact”.
FIGURE B5
FIGURE B5
Variations in gene flow rates inferred from parametric bootstrap of the “full migration model with secondary contact” and “model 10 with secondary contact”.
See this image and copyright information in PMC

Similar articles

See all similar articles

References

    1. Abbott, R. , Albach, D. , Ansell, S. , Arntzen, J. W. , Baird, S. J. E. , Bierne, N. , Boughman, J. , Brelsford, A. , Buerkle, C. A. , Buggs, R. , Butlin, R. K. , Dieckmann, U. , Eroukhmanoff, F. , Grill, A. , Cahan, S. H. , Hermansen, J. S. , Hewitt, G. , Hudson, A. G. , Jiggins, C. , … Zinner, D. (2013). Hybridization and speciation. Journal of Evolutionary Biology, 26(2), 229–246. 10.1111/j.1420-9101.2012.02599.x - DOI - PubMed
    1. Abbott, R. J. , & Brochmann, C. (2003). History and evolution of the arctic flora: in the footsteps of Eric Hultén. Molecular Ecology, 12(2), 299–313. 10.1046/j.1365-294x.2003.01731.x - DOI - PubMed
    1. Adams, J. M. , & Woodward, F. I. (1989). Patterns in tree species richness as a test of the glacial extinction hypothesis. Nature, 339(6227), 699–701. 10.1038/339699a0 - DOI
    1. Bagley, R. K. , Sousa, V. C. , Niemiller, M. L. , & Linnen, C. R. (2017). History, geography and host use shape genomewide patterns of genetic variation in the redheaded pine sawfly (Neodiprion lecontei). Molecular Ecology, 26(4), 1022–1044. 10.1111/mec.13972 - DOI - PubMed
    1. Beichman, A. C. , Huerta‐Sanchez, E. , & Lohmueller, K. E. (2018). Using genomic data to infer historic population dynamics of nonmodel organisms. Annual Review of Ecology, Evolution, and Systematics, 49(1), 433–456. 10.1146/annurev-ecolsys-110617-062431 - DOI

LinkOut - more resources