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Habitat differentiation, hybridization and gene flow patterns in mixed populations of diploid and autotetraploid Dactylorhiza maculata s.l. (Orchidaceae)

Ståhlberg, David LU and Hedrén, Mikael LU (2009) In Evolutionary Ecology 23(2). p.295-328
Abstract
Detailed ecological, morphological and molecular analyses were performed in mixed populations of diploid and autotetraploid Dactylorhiza maculata s.l. in Scandinavia. Comparisons were made with pure populations of either diploid ssp. fuchsii or tetraploid ssp. maculata. It was shown that mixed populations are the result of secondary contact between ssp. fuchsii and ssp. maculata. No patterns of recent and local autopolyploidization were found. Morphology and nuclear DNA markers (internal transcribed spacers of nuclear ribosomal DNA) showed that diploids and tetraploids from mixed populations have similar levels of differentiation to diploids and tetraploids from pure populations. Vegetation analyses, as well as analyses of environmental... (More)
Detailed ecological, morphological and molecular analyses were performed in mixed populations of diploid and autotetraploid Dactylorhiza maculata s.l. in Scandinavia. Comparisons were made with pure populations of either diploid ssp. fuchsii or tetraploid ssp. maculata. It was shown that mixed populations are the result of secondary contact between ssp. fuchsii and ssp. maculata. No patterns of recent and local autopolyploidization were found. Morphology and nuclear DNA markers (internal transcribed spacers of nuclear ribosomal DNA) showed that diploids and tetraploids from mixed populations have similar levels of differentiation to diploids and tetraploids from pure populations. Vegetation analyses, as well as analyses of environmental variables, revealed that diploid and tetraploid individuals in mixed populations are ecologically well differentiated on a microhabitat level. Diploids and tetraploids in pure populations have wider ecological amplitudes than they do in mixed populations. Triploid hybrids grew in intermediate microhabitats between diploids and tetraploids in the mixed populations. Plastid DNA markers indicated that both diploids and tetraploids may act as the maternal parent. Based on morphology and nuclear markers triploids are more similar to tetraploids than to diploids. There were indications of introgressive gene flow between ploidy levels. Plastid markers indicated that gene flow from diploid to tetraploid level is most common, but nuclear markers suggested that gene flow in opposite direction also may occur. Similar patterns of differentiation and gene flow appeared in localities that represented contrasting biogeographic regions. Disturbance and topography may explain why hybridization was slightly more common and the differentiation patterns somewhat less clear in the Scandinavian mountains than in the coastal lowland. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Plastid DNA, Vegetation analysis, Morphometry, Niche differentiation, Introgression, ITS, Dactylorhiza, Hybrid zone, autopolyploidy
in
Evolutionary Ecology
volume
23
issue
2
pages
295 - 328
publisher
Springer
external identifiers
  • wos:000263362600009
  • scopus:60449120748
ISSN
1573-8477
DOI
10.1007/s10682-007-9228-y
language
English
LU publication?
yes
id
424d4418-55b8-4054-ad22-c3eb28022f87 (old id 758427)
date added to LUP
2008-07-22 10:24:43
date last changed
2017-10-22 03:52:31
@article{424d4418-55b8-4054-ad22-c3eb28022f87,
  abstract     = {Detailed ecological, morphological and molecular analyses were performed in mixed populations of diploid and autotetraploid Dactylorhiza maculata s.l. in Scandinavia. Comparisons were made with pure populations of either diploid ssp. fuchsii or tetraploid ssp. maculata. It was shown that mixed populations are the result of secondary contact between ssp. fuchsii and ssp. maculata. No patterns of recent and local autopolyploidization were found. Morphology and nuclear DNA markers (internal transcribed spacers of nuclear ribosomal DNA) showed that diploids and tetraploids from mixed populations have similar levels of differentiation to diploids and tetraploids from pure populations. Vegetation analyses, as well as analyses of environmental variables, revealed that diploid and tetraploid individuals in mixed populations are ecologically well differentiated on a microhabitat level. Diploids and tetraploids in pure populations have wider ecological amplitudes than they do in mixed populations. Triploid hybrids grew in intermediate microhabitats between diploids and tetraploids in the mixed populations. Plastid DNA markers indicated that both diploids and tetraploids may act as the maternal parent. Based on morphology and nuclear markers triploids are more similar to tetraploids than to diploids. There were indications of introgressive gene flow between ploidy levels. Plastid markers indicated that gene flow from diploid to tetraploid level is most common, but nuclear markers suggested that gene flow in opposite direction also may occur. Similar patterns of differentiation and gene flow appeared in localities that represented contrasting biogeographic regions. Disturbance and topography may explain why hybridization was slightly more common and the differentiation patterns somewhat less clear in the Scandinavian mountains than in the coastal lowland.},
  author       = {Ståhlberg, David and Hedrén, Mikael},
  issn         = {1573-8477},
  keyword      = {Plastid DNA,Vegetation analysis,Morphometry,Niche differentiation,Introgression,ITS,Dactylorhiza,Hybrid zone,autopolyploidy},
  language     = {eng},
  number       = {2},
  pages        = {295--328},
  publisher    = {Springer},
  series       = {Evolutionary Ecology},
  title        = {Habitat differentiation, hybridization and gene flow patterns in mixed populations of diploid and autotetraploid Dactylorhiza maculata s.l. (Orchidaceae)},
  url          = {http://dx.doi.org/10.1007/s10682-007-9228-y},
  volume       = {23},
  year         = {2009},
}