Journal Article

Flow cytometry and GISH reveal mixed ploidy populations and <i>Spartina</i> nonaploids with genomes of <i>S. alterniflora</i> and <i>S. maritima</i> origin

Simon Renny-Byfield, Malika Ainouche, Ilia J. Leitch, K. Yoong Lim, Steven C. Le Comber and Andrew R. Leitch

in Annals of Botany

Published on behalf of The Annals of Botany Company

Volume 105, issue 4, pages 527-533
Published in print April 2010 | ISSN: 0305-7364
Published online February 2010 | e-ISSN: 1095-8290 | DOI:
Flow cytometry and GISH reveal mixed ploidy populations and Spartina nonaploids with genomes of S. alterniflora and S. maritima origin

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  • Ecology and Conservation
  • Evolutionary Biology
  • Plant Sciences and Forestry


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The genus Spartina exhibits extensive hybridization and includes classic examples of recent speciation by allopolyploidy. In the UK there are two hexaploid species, S. maritima and S. alterniflora, as well as the homoploid hybrid S. × townsendii (2n = 60) and a derived allododecaploid S. anglica (2n = 120, 122, 124); the latter two are considered to have originated in Hythe, southern England at the end of the 19th century.


Genomic in situ hybridization (GISH) and flow cytometry were used to characterize the genomic composition and distribution of these species and their ploidy levels at Eling Marchwood and Hythe, both near Southampton, southern England.

Key Results

GISH identified approx. 60 chromosomes each of S. maritima and S. alterniflora origin in S. anglica and 62 chromosomes from S. alterniflora and 30 chromosomes from S. maritima in a nonaploid individual from Eling Marchwood, UK. GISH and flow cytometry also revealed that most (94 %) individuals examined at Hythe were hexaploid (the remaining two individuals (6 %) were dodedcaploid; n = 34), whereas hexaploid (approx. 36 % of plants), nonaploid (approx. 27 %) and dodecaploid (approx. 36 %) individuals were found at Eling Marchwood (n = 22).


Nonaploid individuals indicate the potential for introgression between hexaploid and dodecaploid species, complicating the picture of polyploid-induced speciation within the genus. Despite the aggressive ecological habit of S. anglica, it has not out-competed S. × townsendii at Hythe (homoploid hybrids at a frequency of 94 %, n = 34), despite >100 years of coexistence. The success of GISH opens up the potential for future studies of polyploid-induced genome restructuring in this genus.

Keywords: Polyploidy; speciation; Spartina; nonaploid; nonaploid bridge; interspecific hybridization; GISH

Journal Article.  4496 words.  Illustrated.

Subjects: Ecology and Conservation ; Evolutionary Biology ; Plant Sciences and Forestry

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