A comparison of genetic variation and structure in the allopolyploid Platanthera huronensis and its diploid progenitors, Platanthera aquilonis and Platanthera dilatata (Orchidaceae)

作者：Wallace LE^*

来源：Canadian Journal of Botany, 2004, 82(2): 244-252.

DOI：10.1139/B03-147

• genetic structure
• ISSR marker
• Orchidaceae
• platanthera
• allopolyploid

Intersimple sequence repeat (ISSR) markers are used to compare population genetic structure among three widely distributed orchids: Platanthera huronensis (Nuttall) Lindl., an allopolyploid, and its diploid progenitors, Platanthera aquilonis Sheviak, and Platanthera dilatata (Pursh.) Lindl. ex Beck. Platanthera huronensis is very similar to P. dilatata in the level of genetic diversity at both the population and species levels. Populations of P. aquilonis are generally significantly less variable than populations of the other two species, but at the species level, P. aquilonis is more variable than P. dilatata or P. huronensis. Analyses of molecular variance indicated that most of the variation occurs within populations for P. dilatata (Phi(ST) = 0.48, where Phi(ST) is the combined percentage of variation occurring among groups and among populations) and P. huronensis (Phi(ST) = 0.36), and among populations for P. aquilonis (Phi(ST) = 0.69). Populations in disparate regions are not strongly differentiated in P. aquilonis (7% among regions), while in P. dilatata 27% of the variation observed among populations is due to significant regional differences. Platanthera huronensis might be less genetically variable than expected of a widely distributed allopolyploid species due to a limited number of origins, genetic bottlenecks, and low levels of gene flow. Self-pollination via autogamy is a likely cause of the lower level of variation and greater structure observed in P. aquilonis.

• 出版日期2004-2