Evolution and polyploid origins in North American Arctic Puccinellia(Poaceae) based on nuclear ribosomal spacer and chloroplast DNA sequences
The proportion of polyploid plant species increases at higher latitudes, and it has been suggested that original postglacial Arctic immigrants of some large groups, including grasses, were polyploid. We analyzed noncoding nuclear and chloroplast DNA of all North American diploid Puccinellia (Poaceae...
Published in: | American Journal of Botany |
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Main Authors: | , , |
Other Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2010
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Subjects: | |
Online Access: | http://dx.doi.org/10.3732/ajb.0900180 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.3732%2Fajb.0900180 http://onlinelibrary.wiley.com/wol1/doi/10.3732/ajb.0900180/fullpdf |
Summary: | The proportion of polyploid plant species increases at higher latitudes, and it has been suggested that original postglacial Arctic immigrants of some large groups, including grasses, were polyploid. We analyzed noncoding nuclear and chloroplast DNA of all North American diploid Puccinellia (Poaceae) and a subset of arctic polyploids to hypothesize evolutionary relationships among diploids and to evaluate the parentage of polyploids. Diploids formed three lineages: one uniting arctic species P. arctica and P. banksiensis a second comprising arctic species P. tenella, P. alaskana, P. vahliana , and P. wrightii and a third uniting the two temperate species P. lemmonii and P. parishii . The arctic species P. angustata (hexaploid) and P. andersonii (primarily octoploid) apparently derive from the P. arctica‐P. banksiensis lineage based on ITS and chloroplast sequences, and share an ancestor with arctic triploid/tetraploid P. phryganodes based on nrDNA sequences. Sequence comparisons also suggest tetraploid P. bruggemannii evolved from two arctic lineages: P. vahliana‐P. wrightii and P. arctica‐P. banksiensis . These patterns and the predominance of arctic rather than temperate diploid species support the idea that diploid Puccinellia recolonized the Arctic from northern glacial refugia like Beringia, and also formed stabilized polyploid hybrids during these refugial events or subsequently during postglacial colonization. |
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