Abstract
Nepenthaceae, the pitcher plants of the Old World tropics show a remarkable diversity in SE Asia, especially on the islands of Borneo and Sumatra. This region is considered as a secondary center of diversity. Sequence analysis of the cpDNA trn K intron supports this hypothesis showing the species of the Malay Archipelago as neighbour group to the isolated species from Sri Lanka, the Seychelles, and Madagascar. Based on phylogenetic reconstructions an origin of recent Nepenthaceae in the Indian subcontinent is assumed. A recent investigation focused on a non-plastid, translocated copy of the trn K intron has revealed an incongruence to tree topology based on the cpDNA trn K intron. Although the translocated copy emerged as insufficient for phylogenetic reconstruction of Nepenthaceae some taxa showed, contrary to the cpDNA dataset, relatively high distances to the rest of the taxa. These results indicated that the phylogeny of the trn K intron could not reflect true phylogenetic relationships. We investigated the peptide transferase 1 (PTR1), to develop a phylogenetic marker that is based on a nuclear low copy gene in Nepenthes. All sequences obtained were probably functional, indicated by the ratio of point mutations of the single codon positions in exon and intron regions. Comparative analysis showed that this locus is of similar variability as the cpDNA trn K intron and, contrary to the translocated copy of trn K, potential useful for phylogenetic reconstruction. While in parts congruent to the plastid trn K intron phylogeny, a higher divergence of some sequences in PRT1 and in the previously reported, non cpDNA dataset indicates that remnants of an older species stock persisted east of Wallace's line and on the Sunda Shelf. This suggests that plastid haplotypes existing today in the main distribution center of the Nepenthaceae could be descendants of more recently dispersed lineages that had been transmitted to an old species stock.
Key words
Nepenthaceae -
trn K intron - translocated copy - nuclear low copy gene - PTR1
References
The plate tectonics of Cenozoic SE Asia and the distribution of land and sea. Hall, R. and Holloway, J. D., eds. Biogeography and Geological Evolution of SE Asia. Leiden, The Netherlands; Backhuys Publishers (1998): 99-131
Mesozoic and Cenozoic chronostratigraphy and eustatic cycles. Wilgus, C. K. et al., eds. Sea-Level Changes: An Integrated Approach, Special Publ. 42. Tulsa, Oklahoma; Society of Economic Paleontologists and Mineralogists (1988)
Nepenthes L. (Nepenthaceae).
Sendtnera.
(1995);
4
169-174
Nepenthaceae. de Candolle, A. P., ed. Prodromus Systematis Naturalis Regni Vegetalis, Vol. 17. (1873): 90-105
Nepenthes (Nepenthaceae).
Blumea.
(1997);
42
1-106
Nepenthes -Pollen im europäischen Tertiär.
Gleditschia.
(1985);
13
89-93
mat K-sequences with special emphasis on carnivorous taxa.
Plant Biology.
(2000);
2
218-228
trn K intron sequence data.
Plant Biology.
(2001);
3
154-175
http://edoc.ub.uni-muenchen.de/archive/00001078/01/Meimberg_Harald.pdf ). (2002)
trn K intron in the carnivorous genus Nepenthes (Nepenthaceae).
Molecular Phylogenetics and Evolution.
(2006);
39
478-490
Nuphar (Nymphaeaceae): evidence from morphology, chloroplast DNA, and nuclear ribosomal DNA.
American Journal of Botany.
(1999);
86
1316-1324
Malagasy/Indo-Australo-Malesian phytogeographic connections. Lourenco, W. R., ed. Biogeography of Madagascar. Paris; Editions Orstom (1996)
Nepenthes -Arten.
Botanische Jahrbücher für Systematik.
(1979);
100
379-405
Nepenthes .
The Plant Journal.
(1999);
17
101-110
Penstemon sect. Peltanthera (Scrophulariaceae).
Systematic Botany.
(1995);
20
395-412
meimberg@colostate.edu
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