Abstract
Flow cytometry, morphometry and molecular markers [plastid DNA and internal transcribed spacers(ITS) of nuclear ribosomal DNA] were used to determine taxonomic and phylogeographic patterns in Dactylorhiza maculata s.l. from Scandinavia. A total of 238 individuals from 27 populations from throughout all of Scandinavia, including the adjacent Kola Peninsula of Russia, were analyzed. Diploid D. maculata ssp. fuchsii and autotetraploid D. maculata ssp. maculata are morphologically differentiated. Fragment size variants from 10 plastid DNA loci (seven microsatellite loci and three loci with indel variation) were combined to give 43 haplotypes. Three major groups of haplotypes were found. Group I haplotypes were prevalent in the north and the northeast, whereas Group II haplotypes were prevalent in the south and the southwest. Group III was represented by only a single haplotype and appeared to be the result of introgression from D. incarnata s.l. Group I and Group II
haplotypes did not correspond with cytologically and
morphologically defined D. maculata ssp. fuchsii or
D. maculata ssp. maculata. Past introgressive gene flow
rather than recent hybridization is envisaged. Intermediate
Group I haplotypes between Group II and the rest of Group
I were detected in a zone of contact in central Sweden,
which may suggest plastid DNA recombination. The six
ITS alleles scored showed strong positive correlation with
taxonomy. All data sets obtained for ssp. maculata were
significantly correlated with geography. Three different
autotetraploid lineages are hypothesized. One lineage may
represent postglacial immigration from the south and the
other two lineages may represent eastern immigration
routes. Morphology and ITS data suggested that subarctic
populations of ssp. maculata should be recognized as var.
kolaensis.
haplotypes did not correspond with cytologically and
morphologically defined D. maculata ssp. fuchsii or
D. maculata ssp. maculata. Past introgressive gene flow
rather than recent hybridization is envisaged. Intermediate
Group I haplotypes between Group II and the rest of Group
I were detected in a zone of contact in central Sweden,
which may suggest plastid DNA recombination. The six
ITS alleles scored showed strong positive correlation with
taxonomy. All data sets obtained for ssp. maculata were
significantly correlated with geography. Three different
autotetraploid lineages are hypothesized. One lineage may
represent postglacial immigration from the south and the
other two lineages may represent eastern immigration
routes. Morphology and ITS data suggested that subarctic
populations of ssp. maculata should be recognized as var.
kolaensis.
Original language | English |
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Pages (from-to) | 107-132 |
Journal | Plant Systematics and Evolution |
Volume | 273 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 2008 |
Subject classification (UKÄ)
- Ecology
Free keywords
- Introgression
- Flow cytometry
- Dactylorhiza
- Polyploidy
- Plastid DNA
- Morphometry
- ITS