Experimental Hybridizations Among Chromosome Races of Carex pachystachya and the Related Species C. macloviana and C. preslii (Cyperaceae)

Whitkus, Richard

doi:10.2307/2419251

Cited by 44 publications

(61 citation statements)

References 15 publications

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“…It clusters well in section Ovales, but the relationship to other species of the section remains unresolved. The disjunct distribution of C. macloviana and many closely related species in North America (Whitkus and Packer 1984, Whitkus 1988 would be worth detailed investigations.…”

Section: Discussionmentioning

confidence: 99%

Phylogenetic relationships in Carex , subgenus Vignea (Cyperaceae), based on ITS sequences

Hendrichs

Michalski

Begerow

et al. 2004

Plant Systematics and Evolution

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Abstract. To evaluate the sectional classification in Carex, subgenus Vignea, the ITS region of 58 species of 20 sections was analyzed with Neighbor Joining (NJ) and Markov chain Monte Carlo (MCMC) methods. Sections Dioicae, Physodeae and Ovales are found to be monophyletic, with C. bohemica well integrated in the section Ovales. Section Heleonastes turns out to be monophyletic, if C. canescens is treated separately in section Canescentes. Section Elongatae is monophyletic, but C. remota is placed in section Remotae and C. bromoides in section Deweyanae. In both analyses, six representatives of section Arenariae cluster together in a terminal group, whereas C. disticha, C. repens and C. siccata form a basal cluster. C. maritima, as the only member of section Incurvae, shares this basal position. C. chordorrhiza is ascribed to section Chordorrhizeae and not ascribed to the paraphyletic section Divisae. C. vulpina and C. otrubae are assigned to section Vulpinae and separated from the heterogeneous section Stenorhynchae. The other members of sections Divisae, Muehlenbergianae, Multiflorae and Stenorhynchae are scattered throughout the trees. The representatives of section Foetidae are dispersed in both analyses, section Paniculatae appears to be non-monophyletic in the molecular results as well. The subgenus appears subdivided in at least four larger subgroups in all analyses. Whereas these subgroups are strongly supported, the relationships between these subgroups remain only poorly resolved.

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Section: Discussionmentioning

confidence: 99%

Phylogenetic relationships in Carex , subgenus Vignea (Cyperaceae), based on ITS sequences

Hendrichs

Michalski

Begerow

et al. 2004

Plant Systematics and Evolution

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“…This form of chromosomal evolution is referred to as agmatoploidy or quantitative aneuploidy (Greilhuber 1995). The potential for rapid chromosomal evolution has been hypothesized to play an important role in the diversification of sedges, either through reduced hybrid fitness (Whitkus 1988b) or the rearrangement of ecologically significant linkage groups (Whitkus 1988a). Addressing this hypothesis for increased sedge speciation using cytogenetic, ecological, and biosystematic methods is certain to be one of the central goals of sedge systematics in the coming decades.…”

Section: Chromosomal Evolution and Sedge Speciationmentioning

confidence: 99%

“…Extensive taxonomic work in the eastern North American members of sect. Ovales over the past decade (Rothrock 1991;Reznicek 1993;Reznicek and Rothrock 1997;Rothrock et al 1997;Rothrock and Reznicek 2001) has made it possible to sample what is believed to be every species within ENA clade I, and extensive chromosome counting across a wide phylogenetic range of the section (Whitkus 1991;Reznicek 1996, 1998) allows us to address Heilborn's hypotheses at several phylogenetic scales. Future work using the data presented in this paper will address analytical issues related to phylogenetic reconstruction using AFLP data and reconstruction of character evolution that can only be touched upon in this paper, as well as patterns of ecological, biogeographic, and morphological evolution.…”

Section: Chromosomal Evolution and Sedge Speciationmentioning

confidence: 99%

“…Means for each lineage were calculated as the average of the median chromosome count found within each taxon sampled. Chromosome numbers were taken from the three most recent and thorough reviews of chromosome numbers in the section (Whitkus 1991;Reznicek 1996, 1998) and unpublished counts by P. E. Rothrock. Species were assigned to each clade based on nrDNA data (Hipp and Rothrock 2002;Hipp in press).…”

Section: Analysis Of Chromosomal Datamentioning

confidence: 99%

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Chromosome Number Changes Associated with Speciation in Sedges: a Phylogenetic Study in Carex section Ovales (Cyperaceae) Using AFLP Data

Hipp¹,

Rothrock²,

Reznicek³

et al. 2007

aliso

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Phylogenetic analysis of amplified fragment length polymorphisms (AFLP) was used to infer patterns of morphologic and chromosomal evolution in an eastern North American group of sedges (ENA clade I of Carex sect. Ovales). Distance analyses of AFLP data recover a tree that is topologically congruent with previous phylogenetic estimates based on nuclear ribosomal DNA (nrDNA) sequences and provide support for four species groups within ENA clade I. A maximum likelihood method designed for analysis of restriction site data is used to evaluate the strength of support for alternative topologies. While there is little support for the precise placement of the root, the likelihood of topologies in which any of the four clades identified within the ENA clade I is forced to be paraphyletic is much lower than the likelihood of the optimal tree. Chromosome counts for a sampling of species from throughout sect. Ovales are mapped onto the tree, as well as counts for all species in ENA clade I. Parsimony reconstruction of ancestral character states suggest that: (1) Heilborn's hypothesis that more highly derived species in Carex have higher chromosome counts does not apply within sect. Ovales, (2) the migration to eastern North America involved a decrease in average chromosome count within sect. Ovales, and (3) intermediate chromosome counts are ancestral within ENA clade I. A more precise understanding of chromosomal evolution in Carex should be possible using likelihood analyses that take into account the intraspecific polymorphism and wide range of chromosome counts that characterize the genus.

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“…Matings between different aneuploids belonging to the same or the closely related taxa and hybridization are also thought to contribute to the origin of new aneuploids and the maintenance of them in populations (Cayouette and Morisette 1985, Cayouette and Catling 1992, Faulkner 1973, Hoshino et al 1993, Hoshino and Waterway 1994, Whitkus 1988. It is therefore expected that aneuploids in Carex are frequently created, and then subjected to a variety of selection under various environmental conditions.…”

mentioning

confidence: 99%

Chromosome Numbers and Their Variation Patterns of Carex in the Ryukyu Islands.

Ohkawa

Yokota

1998

CYTOLOGIA

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Summary Chromosome numbers for 13 species, including 12 new counts, were reported for Carex distributed in the Ryukyu Islands. Intraspecific aneuploidy (sensu lato) was found in four species and the different types of chromosome number variation pattern within and among populations were recognized in this study. In three species, C. fulvo-rubescens, C. nemostachys and C. sakonis, several intraspecific aneuploid cytotypes were found in the same population. Additionally, notable disturbances of chromosome associations at meiosis were often observed, especially in C. sakonis, and therefore the compatibility among aneuploid cytotypes of these species was readily predictable. In C. sociata, on the other hand, no chromosome number variations within populations and stable chromosome associations at meiosis were found in all investigated populations, and suggesting that these aneuploid cytotypes have differentiated at least to the population level. These two types of variation pattern may indicate that the different aneuploidy mechanisms have operated in Carex population differentiation.

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Experimental Hybridizations Among Chromosome Races of Carex pachystachya and the Related Species C. macloviana and C. preslii (Cyperaceae)

Cited by 44 publications

References 15 publications

Phylogenetic relationships in Carex , subgenus Vignea (Cyperaceae), based on ITS sequences

Phylogenetic relationships in Carex , subgenus Vignea (Cyperaceae), based on ITS sequences

Chromosome Number Changes Associated with Speciation in Sedges: a Phylogenetic Study in Carex section Ovales (Cyperaceae) Using AFLP Data

Chromosome Numbers and Their Variation Patterns of Carex in the Ryukyu Islands.

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