Karyosystematic studies onRubiaceae: Chromosome counts from Sri Lanka

Kiehn, Michael

doi:10.1007/bf00990124

Cited by 19 publications

(12 citation statements)

References 11 publications

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“…However, we detected no intraindividual polymorphism in the two individuals of Nauclea orientalis, even though it is octoploid, nor did we find any in the remaining taxa. This result is consistent with small amounts of DNA for the haploid chromosome sets in N. orientalis, an indication of an already homogenized, old polyploid (Kiehn, 1986(Kiehn, , 1995. If polymorphism were the result of hybridization and/or allopolyploidy, there would be some evidence of this from comparison with chloroplast gene trees.…”

Section: Correlates Of High Levels Of Polymorphismsupporting

confidence: 83%

“…Except for the octoploid Nauclea orientalis (Kiehn and Lorence, 1996), all taxa investigated so far in Naucleeae (e.g., Mitragyna parviflora [Mehra and Gill, 1968], M. rubrostipulata [Kiehn, 1985], Uncaria elliptica [Kiehn, 1986], Adina pilulifera, A. rubella, Breonia chinensis, Cephalanthus glabratus, C. occidentalis, Haldina cordifolia, Nauclea diderrichii, N. xanthoxylon, Neolamarckia cadamba, Sarcocephalus latifolius, and S. pobeguinii [Kiehn, 1995]) are tetraploid. If polymorphism were a simple result of polyploidy, we would find it in all species of Naucleeae.…”

Section: Correlates Of High Levels Of Polymorphismmentioning

confidence: 99%

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Recent Origin and Phylogenetic Utility of Divergent ITS Putative Pseudogenes: A Case Study from Naucleeae (Rubiaceae)

2004

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The internal transcribed spacer (ITS) of nuclear ribosomal DNA has been widely used by systematists for reconstructing phylogenies of closely related taxa. Although the occurrence of ITS putative pseudogenes is well documented for many groups of animals and plants, the potential utility of these pseudogenes in phylogenetic analyses has often been underestimated or even ignored in part because of deletions that make unambiguous alignment difficult. In addition, long branches often can lead to spurious relationships, particularly in parsimony analyses. We have discovered unusually high levels of ITS polymorphism (up to 30%, 40%, and 14%, respectively) in three tropical tree species of the coffee family (Rubiaceae), Adinauclea fagifolia, Haldina cordifolia, and Mitragyna rubrostipulata. Both secondary structure stability and patterns of nucleotide substitutions in a highly conserved region (5.8S gene) were used for distinguishing presumed functional sequences from putative pseudogenes. The combination of both criteria was the most powerful approach. The sequences from A. fagifolia appear to be a mix of functional genes and highly distinct putative pseudogenes, whereas those from H. cordifolia and M. rubrostipulata were identified as putative pseudogenes. We explored the potential utility of the identified putative pseudogenes in the phylogenetic analyses of Naucleeae sensu lato. Both Bayesian and parsimony trees identified the same monophyletic groups and indicated that the polymorphisms do not transcend species boundaries, implying that they do not predate the divergence of these three species. The resulting trees are similar to those produced by previous analyses of chloroplast genes. In contrast to results of previous studies therefore, divergent putative pseudogenes can be useful for phylogenetic analyses, especially when no sequences of their functional counterparts are available. Our studies clearly show that ITS polymorphism may not necessarily mislead phylogenetic inference. Despite using many different PCR conditions (different primers, higher denaturing temperatures, and absence or presence of DMSO and BSA-TMACl), we recovered only a few functional ITS copies from A. fagifolia and none from H. cordifolia and M. rubrostipulata, which suggests that PCR selection is occurring and/or the presumed functional alleles are located at minor loci (with few ribosomal DNA copies).

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Section: Correlates Of High Levels Of Polymorphismsupporting

confidence: 83%

Section: Correlates Of High Levels Of Polymorphismmentioning

confidence: 99%

Recent Origin and Phylogenetic Utility of Divergent ITS Putative Pseudogenes: A Case Study from Naucleeae (Rubiaceae)

2004

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“…dIscussIon C. ipecacuanha is a diploid species with 11 bivalents. the basic number of the genus Cephaelis (= Psychotria l.) is x = 11 (Kiehn, 1986). According to Assis (1992), the karyotype of C. ipecacuanha is symmetric, displaying metacentric chromosomes, and is included among the more primitive types.…”

Section: Pollen Size and Viabilitymentioning

confidence: 99%

Reproductive studies on ipecac (Cephaelis ipecacuanha (Brot.) A. Rich; Rubiaceae): meiotic behavior and pollen viability

Souza

Martins

Pereira³

et al. 2006

Braz. J. Biol.

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Reproductive studies were carried out on Brazilian accessions of ipecac, Cephaelis ipecacuanha. Meiotic behavior was studied using the squashing technique. Irregular chromosome segregation in meiosis I and II, many sets of chromosomes in telophase II, micronuclei, incorrect cytoplasm division, incomplete cytokinesis and anomalous post-meiotic products, mainly polyads, were observed. The mean meiotic index was lower than 72%. Pollen viability was analyzed using Alexander solution, and the percentages ranged between brevistylous and longistylous floral morphs (85.3 to 93.1%), and among different localities (82.5 to 92.6%) analyzed. The size of pollen ranged between viable and sterile, and empty and shrunken sterile. In its natural habitat, this species is known to propagate by vegetative multiplication, but sexual reproduction seems to be as important as the vegetative propagation to this species.

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“…Verdcourt (1958) e Kiehn (1986) comentam que o número básico de cromossomos para Psychotria L. é x = 11. Além disso, Kiehn (1986) reporta para Psychotria bisulcata, espé-cie originária da Índia, n = 11. Esses números são concordantes com o número cromossômico encontrado para Psychotria ipecacuanha (Brot.)…”

Section: Cephaelis Acuminata Karsten Nomen Nudumunclassified

Diferenciação morfológica e anatômica em populações de "ipecacuanha" - Psychotria ipecacuanha (Brot.) Stokes (Rubiaceae)

Assis¹,

Giulietti²

1999

Rev. bras. Bot.

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Diferenciação morfológica e anatômica em populações de "ipecacuanha" -Psychotria ipecacuanha (Brot. ABSTRACT -(Morphological and anatomical differentiation in populations of "ipecacuanha" -Psychotria ipecacuanha (Brot.) Stokes (Rubiaceae)). Psychotria ipecacuanha is a medicinal plant of the Rubiaceae family. The roots are very important for the production of emetine. The species presents a disjunction in its geographical distribution. It occurs in Central America (from Nicaragua to Northwestern America do Sul) and in Brazil: in the Southern Amazonian Forest (Rondônia and Mato Grosso) and in the Atlantic Forest (Pernambuco to Paraná). Morphological data of populations from the three areas were used to establish the circunscription of the species and the possible infra-specific taxa. It was concluded, through the analysis of major components, that there are no significant differences among the individuals of the populations. The few individual differences observed are not related to the geographic distribution of the populations, so the "ipecacuanha" was considerated single species Psychotria ipecacuanha (Brot.) Stokes. In addition to the taxonomical analysis, some anatomical and chromosomal data are presented here.)RESUMO -(Diferenciação morfológica e anatômica em populações de "ipecacuanha" Psychotria ipecacuanha (Brot.) Stokes (Rubiaceae)). Psychotria ipecacuanha é uma espécie medicinal da família Rubiaceae, importante pela produção em suas raízes do alcalóide emetina. Foram feitas análises das três populações disjuntas que compõem a espécie e que ocorrem na América Central (Nicarágua, Costa Rica e Panamá) e Colômbia, sul da Floresta Amazônica (Rondônia e Mato Grosso) e Mata Atlântica (Pernambuco até Paraná). Foram utilizados, no estabelecimento dos limites inter e intraespecíficos, todos os dados morfológicos vegetativos e reprodutivos disponíveis e feita análise dos componentes principais, que permitiram concluir que não existem diferenças significativas entre as populações examinadas. As poucas diferenças individuais observadas não estão relacionadas com a distribuição geográfica das populações examinadas. Como conclusão, a ipecacuanha ao longo de toda sua distribuição geográfica foi considerada como uma só espécie, Psychotria ipecacuanha (Brot.) Stokes. Além da análise taxonômica, são apresentados neste trabalho dados anatômicos e sobre o número de cromossomos da espécie.

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Karyosystematic studies onRubiaceae: Chromosome counts from Sri Lanka

Cited by 19 publications

References 11 publications

Recent Origin and Phylogenetic Utility of Divergent ITS Putative Pseudogenes: A Case Study from Naucleeae (Rubiaceae)

Recent Origin and Phylogenetic Utility of Divergent ITS Putative Pseudogenes: A Case Study from Naucleeae (Rubiaceae)

Reproductive studies on ipecac (Cephaelis ipecacuanha (Brot.) A. Rich; Rubiaceae): meiotic behavior and pollen viability

Diferenciação morfológica e anatômica em populações de "ipecacuanha" - Psychotria ipecacuanha (Brot.) Stokes (Rubiaceae)

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