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matK Sequences (matk + sequence)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Molecular Phylogeny of Caryophyllidae s.l. Based on MatK Sequences with Special Emphasis on Carnivorous Taxa

PLANT BIOLOGY, Issue 2 2000
H. Meimberg
Abstract: Despite intensive morphological, chemical and cladistic studies on Caryophyllidae, the circumscription of this subclass and the interfamilial relationships are still under discussion. Using comparative sequencing of the chloroplast matK gene, hypotheses of relationships between the carnivorous Droseraceae, Nepenthaceae and Dioncophyllaceae and ten other families of the Caryophyllidae s.l. were tested and compared with previously published cladograms based on rbcL, 18S rDNA and ORF2280 sequences. Parsimony analyses indicate two well-differentiated clades. One strongly supported clade comprises the carnivorous families Droseraceae and Nepenthaceae, along with its close relatives Dioncophyllaceae and Ancistrocladaceae. The second clade is restricted to the Polygonaceae, Plumbaginaceae, Tamaricaceae and Frankeniaceae. The Simmondsiaceae are more closely related to Caryophyllales and are at the base of the remaining taxa. Results of this analysis suggest that carnivory within Caryophyllidae s.l. has a monophyletic origin and, with the exception of Triphyophyllum, this syndrome was lost in the taxa of Dioncophyllaceae and Ancistrocladaceae. The exclusion of Drosophyllum from Droseraceae suggests no close relationship with this family. Finally, the data support a sister group relationship between the Plumbaginaceae and Polygonaceae and the Frankeniaceae and Tamaricaceae. An extensive survey of the rpl2 intron via PCR amplification indicates that the intron is absent from chloroplast genomes of Droseraceae and all taxa of Caryophyllales, but is present in Drosophyllum. Consequently, there is evidence for a multiple loss of the intron and strong support that Drosophyllum has affinities outside the Droseraceae. Our sequence data corroborate many aspects of recent cladistic analyses based predominantly on rbcL sequences. This study shows that matK sequences are useful for'phylogenetic inference among closely related members of Caryophyllidae. [source]

Molecular systematics in the genus Clintonia and related taxa based on rbcL and matK gene sequence data

PLANT SPECIES BIOLOGY, Issue 2 2001
Kazuhiko Hayashi
Abstract In an attempt to elucidate the affinity and phylogeny of the disjunct North American,eastern Asian genus Clintonia, two chloroplast genes, rbcL and matK, were sequenced for all five species (Clintonia andrewsiana, Clintonia borealis, Clintonia umbellulata, Clintonia uniflora and Clintonia udensis). Similar sequence data sets for both genes supported the idea that a monophyly of Clintonia consists of two clades, one in eastern Asia and one in North America. The North American lineage resolves into an eastern group and a western group. There are surprisingly few site substitutions within these two genes, notwithstanding the wide morphological diversity of the genus. To root the Clintonia trees, Cardiocrinum (=Lilium) cordatum, Medeola virginiana, Scoliopus bigelovii and Scoliopus hallii were used as outgroup taxa. Similar topologies for Clintonia resulted when both the rbcL and matK gene sequences were combined. However, when an amino acid tree was generated for the matK sequence, all differences between the North American species were reduced to similarities due to synonymous codon sequences. Differentiation patterns of some selected morphological, karyological and embryological characters in Clintonia were also reviewed in comparison to the resulting molecular topologies. The unique, Clintonia -type megasporogenesis that produced identical, maternally derived, diploid zygotes and endosperm coupled to polyploid buffering provides a considerable constraint on variability. A search of possible sister genera to Clintonia was also attempted based on the molecular analyses and outgroup analysis, and Medeola virginiana from eastern North America turned out to be the closest relative found. [source]

Evolution and biogeography of the austral genus Phyllocladus (Podocarpaceae)

JOURNAL OF BIOGEOGRAPHY, Issue 10 2004
Steven J. Wagstaff
Abstract Aim, To infer evolutionary relationships within the genus Phyllocladus and among its close relatives by phylogenetic analysis of DNA sequences. Interpret the inferred relationships in association with the fossil record to examine the origin and diversification of the genus. Location, Australasia. Methods, Phylogenetic analyses of rbcL, matK and internal transcribed spacer (ITS) sequences representing all of the extant species of Phyllocladus and a selection of outgroups from Podocarpaceae and Araucariaceae. Results, The rbcL and matK sequences exhibit little variation within Phyllocladus, but ally its members to Podocarpaceae although its immediate sister remains unclear. The ITS sequences resolve all five species of Phyllocladus and two intraspecific ecotypes of P. alpinus. Main conclusions,Phyllocladus forms a distinct lineage that diverged early in the evolutionary history of Podocarpaceae. The fossil record indicates that the genus was more widely distributed and morphologically diverse during the early Tertiary than at present. Although of Mesozoic origin, the level of sequence variation within Phyllocladus suggests that the extant species radiated during the late Tertiary c. 6.3 ± 0.9 Ma. New Zealand is the present centre of species diversity. [source]