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Hybridization, polyploidy and speciation in Spartina (Poaceae)
Author(s) -
Ainouche Malika L.,
Baumel Alex,
Salmon Armel,
Yannic Glenn
Publication year - 2004
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.2003.00926.x
Subject(s) - biology , genetic algorithm , genome , ploidy , evolutionary biology , lineage (genetic) , reticulate evolution , spartina alterniflora , perennial plant , sister group , genus , botany , phylogenetics , genetics , ecology , gene , clade , wetland , marsh
Summary Hybridization and polyploidy are well illustrated in the genus Spartina . This paper examines how recent molecular approaches have helped our understanding of the past and recent reticulate history of species, with special focus on allopolyploid speciation. Spartina species are tetraploid, hexaploid or dodecaploid perennials, most of them being native to the New World. The molecular phylogeny indicates an ancient split between the tetraploid and the hexaploid species, with S . argentinensis as sister to the hexaploid lineage. Recent hybridization and polyploidization events involved hexaploid species, resulting from introductions of the east‐American S. alterniflora . In California, ongoing hybridizations with its sister species S. foliosa result in introgressant hybrid swarms. In Europe, hybridization with S. maritima resulted in S . × neyrautii (France) and S. × townsendii (England), with. S. alterniflora as the maternal parent. The allopolyploid S. anglica resulted from chromosome doubling of S . × townsendii. This young allopolyploid contains divergent homoeologous subgenomes that have not undergone significant changes since their reunion. Hybridization, rather than genome duplication, appears to have shaped the allopolyploid genome at both the structural and epigenetic levels.