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Biogeography of the Phalaenopsis amabilis species complex inferred from nuclear and plastid DNAs.

Tsai CC, Chou CH, Wang HV, Ko YZ, Chiang TY, Chiang YC - BMC Plant Biol. (2015)

Bottom Line: Demographic growth associated with the climatic oscillations in the Würm glacial period followed the species splits.Nevertheless, a subsequent population slowdown occurred in the late LGM due to extinction of regional populations.The reduction of suitable habitats resulted in geographic fragmenttation of the remaining taxa.

View Article: PubMed Central - PubMed

Affiliation: Crop Improvement Division, Kaohsiung District Agricultural Improvement Station, Pingtung, 900, Taiwan. tsaicc@mail.kdais.gov.tw.

ABSTRACT

Background: Phalaenopsis is one of the important commercial orchids in the world. Members of the P. amabilis species complex represent invaluable germplasm for the breeding program. However, the phylogeny of the P. amabilis species complex is still uncertain. The Phalaenopsis amabilis species complex (Orchidaceae) consists of subspecies amabilis, moluccana, and rosenstromii of P. amabilis, as well as P. aphrodite ssp. aphrodite, P. ap. ssp. formosana, and P. sanderiana. The aims of this study were to reconstruct the phylogeny and biogeographcial patterns of the species complex using Neighbor Joining (NJ), Maxinum Parsimony (MP), Bayesian Evolutionary Analysis Sampling Trees (BEAST) and Reconstruct Ancestral State in Phylogenies (RASP) analyses based on sequences of internal transcribed spacers 1 and 2 from the nuclear ribosomal DNA and the trnH-psbA spacer from the plastid DNA.

Results: A pattern of vicariance, dispersal, and vicariance + dispersal among disjunctly distributed taxa was uncovered based on RASP analysis. Although two subspecies of P. aphrodite could not be differentiated from each other in dispersal state, they were distinct from P. amabilis and P. sanderiana. Within P. amabilis, three subspecies were separated phylogenetically, in agreement with the vicariance or vicariance + dispersal scenario, with geographic subdivision along Huxley's, Wallace's and Lydekker's Lines. Molecular dating revealed such subdivisions among taxa of P. amabilis complex dating back to the late Pleistocene. Population-dynamic analyses using a Bayesian skyline plot suggested that the species complex experienced an in situ range expansion and population concentration during the late Last Glacial Maximum (LGM).

Conclusions: Taxa of the P. amabilis complex with disjunct distributions were differentiated due to vicariance or vicariance + dispersal, with events likely occurring in the late Pleistocene. Demographic growth associated with the climatic oscillations in the Würm glacial period followed the species splits. Nevertheless, a subsequent population slowdown occurred in the late LGM due to extinction of regional populations. The reduction of suitable habitats resulted in geographic fragmenttation of the remaining taxa.

No MeSH data available.


The effective population size over time for all accessions in the P. amabilis species complex based on the cpDNA trnH-psbA spacer using Bayesian skyline plots analyses. The Last Glacial Maximum (LGM) is green color shaded. Solid lines indicate median estimations; area between gray dash lines indicates 95 % confidence intervals
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Fig4: The effective population size over time for all accessions in the P. amabilis species complex based on the cpDNA trnH-psbA spacer using Bayesian skyline plots analyses. The Last Glacial Maximum (LGM) is green color shaded. Solid lines indicate median estimations; area between gray dash lines indicates 95 % confidence intervals

Mentions: A Bayesian skyline plot was used to estimate population dynamics. Plastid DNA showed historical demographic growth followed by recent steadiness in the P. amabilis complex in the late LGM due to extinction of regional populations (Fig. 4). Mismatch analyses of plastid DNA sequences displayed a multimodal distribution pattern with a non-significant sum of squared deviations (SSD) statistic and the raggedness index (HRag) value under both sudden- and spatial-expansion models in the P. amabilis complex (Table 6). In addition, negative Fu’s FS values suggested demorgraphic expansion under both sudden- and spatial-expansion model in P. amabilis (Table 6).Fig. 4


Biogeography of the Phalaenopsis amabilis species complex inferred from nuclear and plastid DNAs.

Tsai CC, Chou CH, Wang HV, Ko YZ, Chiang TY, Chiang YC - BMC Plant Biol. (2015)

The effective population size over time for all accessions in the P. amabilis species complex based on the cpDNA trnH-psbA spacer using Bayesian skyline plots analyses. The Last Glacial Maximum (LGM) is green color shaded. Solid lines indicate median estimations; area between gray dash lines indicates 95 % confidence intervals
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4537552&req=5

Fig4: The effective population size over time for all accessions in the P. amabilis species complex based on the cpDNA trnH-psbA spacer using Bayesian skyline plots analyses. The Last Glacial Maximum (LGM) is green color shaded. Solid lines indicate median estimations; area between gray dash lines indicates 95 % confidence intervals
Mentions: A Bayesian skyline plot was used to estimate population dynamics. Plastid DNA showed historical demographic growth followed by recent steadiness in the P. amabilis complex in the late LGM due to extinction of regional populations (Fig. 4). Mismatch analyses of plastid DNA sequences displayed a multimodal distribution pattern with a non-significant sum of squared deviations (SSD) statistic and the raggedness index (HRag) value under both sudden- and spatial-expansion models in the P. amabilis complex (Table 6). In addition, negative Fu’s FS values suggested demorgraphic expansion under both sudden- and spatial-expansion model in P. amabilis (Table 6).Fig. 4

Bottom Line: Demographic growth associated with the climatic oscillations in the Würm glacial period followed the species splits.Nevertheless, a subsequent population slowdown occurred in the late LGM due to extinction of regional populations.The reduction of suitable habitats resulted in geographic fragmenttation of the remaining taxa.

View Article: PubMed Central - PubMed

Affiliation: Crop Improvement Division, Kaohsiung District Agricultural Improvement Station, Pingtung, 900, Taiwan. tsaicc@mail.kdais.gov.tw.

ABSTRACT

Background: Phalaenopsis is one of the important commercial orchids in the world. Members of the P. amabilis species complex represent invaluable germplasm for the breeding program. However, the phylogeny of the P. amabilis species complex is still uncertain. The Phalaenopsis amabilis species complex (Orchidaceae) consists of subspecies amabilis, moluccana, and rosenstromii of P. amabilis, as well as P. aphrodite ssp. aphrodite, P. ap. ssp. formosana, and P. sanderiana. The aims of this study were to reconstruct the phylogeny and biogeographcial patterns of the species complex using Neighbor Joining (NJ), Maxinum Parsimony (MP), Bayesian Evolutionary Analysis Sampling Trees (BEAST) and Reconstruct Ancestral State in Phylogenies (RASP) analyses based on sequences of internal transcribed spacers 1 and 2 from the nuclear ribosomal DNA and the trnH-psbA spacer from the plastid DNA.

Results: A pattern of vicariance, dispersal, and vicariance + dispersal among disjunctly distributed taxa was uncovered based on RASP analysis. Although two subspecies of P. aphrodite could not be differentiated from each other in dispersal state, they were distinct from P. amabilis and P. sanderiana. Within P. amabilis, three subspecies were separated phylogenetically, in agreement with the vicariance or vicariance + dispersal scenario, with geographic subdivision along Huxley's, Wallace's and Lydekker's Lines. Molecular dating revealed such subdivisions among taxa of P. amabilis complex dating back to the late Pleistocene. Population-dynamic analyses using a Bayesian skyline plot suggested that the species complex experienced an in situ range expansion and population concentration during the late Last Glacial Maximum (LGM).

Conclusions: Taxa of the P. amabilis complex with disjunct distributions were differentiated due to vicariance or vicariance + dispersal, with events likely occurring in the late Pleistocene. Demographic growth associated with the climatic oscillations in the Würm glacial period followed the species splits. Nevertheless, a subsequent population slowdown occurred in the late LGM due to extinction of regional populations. The reduction of suitable habitats resulted in geographic fragmenttation of the remaining taxa.

No MeSH data available.