Chromosome Numbers and Dimensions, Species-Formation and Phylogeny in the Genus Carex

Heilborn, Otto

doi:10.1111/j.1601-5223.1924.tb03128.x

Cited by 90 publications

(27 citation statements)

References 23 publications

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“…In contrast to organisms with monocentric chromosomes where acentric fragments are mostly lost during cell division, the breakage of holocentric chromosomes creates fragments with normal centromere activity. Therefore, no lagging anaphase chromosomes and micronuclei occur, and chromosome breakage and translocation events play an important role in the fast karyotype evolution of holocentric species (Heilborn 1924;Brown et al 2004;Kuta et al 2004;Da Silva et al 2008;Hipp et al 2009). …”

Section: Discussionmentioning

confidence: 98%

Holokinetic centromeres and efficient telomere healing enable rapid karyotype evolution

et al. 2015

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Species with holocentric chromosomes are often characterized by a rapid karyotype evolution. In contrast to species with monocentric chromosomes where acentric fragments are lost during cell division, breakage of holocentric chromosomes creates fragments with normal centromere activity. To decipher the mechanism that allows holocentric species an accelerated karyotype evolution via chromosome breakage, we analyzed the chromosome complements of irradiated Luzula elegans plants. The resulting chromosomal fragments and rearranged chromosomes revealed holocentromere-typical CENH3 and histone H2AThr120ph signals as well as the same mitotic mobility like unfragmented chromosomes. Newly synthesized telomeres at break points become detectable 3 weeks after irradiation. The presence of active telomerase suggests a telomerase-based mechanism of chromosome healing. A successful transmission of holocentric chromosome fragments across different generations was found for most offspring of irradiated plants. Hence, a combination of holokinetic centromere activity and the fast formation of new telomeres at break points enables holocentric species a rapid karyotype evolution involving chromosome fissions and rearrangements.

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Section: Discussionmentioning

confidence: 98%

Holokinetic centromeres and efficient telomere healing enable rapid karyotype evolution

et al. 2015

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“…In post-reductional meiosis, this order is reversed (Battaglia & Boyes, 1955). Post-reductional meiosis was first observed in Carex by Heilborn (1928) and demonstrated conclusively by Wahl (1940). Battaglia and Boyes (1955) regrettably did not discuss Carex at length in their seminal review on the topic, apparently because Tanaka (1937Tanaka ( , 1939Tanaka ( , 1940aTanaka ( , b, c, 1941a had reported pre-reductional meiosis from the Cyperaceae.…”

Section: Cytological Characteristics Of the Cyperaceaementioning

confidence: 91%

“…The genus Carex L. exhibits a particularly exceptional aneuploid series, ranging from n=6 to n=66 (Tanaka, 1949), with every number from n=6 to n=47 represented by at least one species (Roalson et al, 2007). Intraspecific variation in Carex is equally remarkable: although chromosome number was initially thought to be invariant within species (Heilborn, 1924;Löve et al, 1957), more than 100 Carex species are known to comprise numerous cytotypes, with some taxa spanning a range of ten haploid (n) chromosomes from highest to lowest count (Wahl, 1940;Tanaka, 1948Tanaka, , 1949Davies, 1956;Cayouette & Morisset, 1986a;Whitkus, 1991;Hoshino, 1992;Rothrock & Reznicek, 1998). Despite an enormous amount of chromosome counting in the Cyperaceae, there are substantial gaps in our knowledge of the pattern and process of chromosome evolution in the genus.…”

Section: Introductionmentioning

confidence: 97%

The Evolution of Chromosome Arrangements in Carex (Cyperaceae)

2008

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Sedges (Carex: Cyperaceae) exhibit remarkable agmatoploid chromosome series between and within species. This chromosomal diversity is due in large part to the structure of the holocentric chromosomes: fragments that would not be heritable in organisms with monocentric chromosomes have the potential to produce viable gametes in organisms with holocentric chromosomes. The rapid rate of chromosome evolution in the genus and high species diversification rate in the order (Cyperales Hutch., sensu Dahlgren) together suggest that chromosome evolution may play an important role in the evolution of species diversity in Carex. Yet the other genera of the Cyperaceae and their sister group, the Juncaceae, do not show the degree of chromosomal variation found in Carex, despite the fact that diffuse centromeres are a synapomorphy for the entire clade. Moreover, fission and fusion apparently account for the majority of chromosome number changes in Carex, with relatively little duplication of whole chromosomes, whereas polyploidy is relatively important in the other sedge genera. In this paper, we review the cytologic and taxonomic literature on chromosome evolution in Carex and identify unanswered questions and directions for future research. In the end, an integration of biosystematic, cytogenetic, and genomic studies across the Cyperaceae will be needed to address the question of what role chromosome evolution plays in species diversification within Carex and the Cyperaceae as a whole.

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“…Carex arenaria L. 60-64 Rohweder, H., 193764 Wulff, H. D., 1937a58 Tanaka, N., 1942c58 Tanaka, N., 194829 Delay, J., 1971 34, 35, 38 Tanaka, N., 1938a34, 38, 42 Okuno, S., 193934, 35, 38 Tanaka, N., 1939b34, 38 Funabiki, K., 1958b16, 18 32, 36 Hoshino, T. & K. Okamoto, 197916-19 32-38 Hoshino, T., 198016-22 32, 34, 36-38 Hoshino, T., 1981a32, 34, 36, 38 Hoshino, T., 198932-34, 36-38 Hoshino, T. & K. Okamura, 1993Heilborn, O., 1939Hindakova, M., 1978 A Synopsis of Chromosome Number Variation in the Cyperaceae irr. 89 Halkka, L., H. -10, 12-13, 18, 20, 24, 26 Hoshino, T., 1981a…”

Section: Refmentioning

confidence: 98%

A Synopsis of Chromosome Number Variation in the Cyperaceae

Roalson

2008

Bot. Rev

110

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The Cyperaceae are well known for having a large amount of variation in chromosome numbers both within and among genera. Most of this variation has been previously attributed to agmatoploid or qualitative aneuploid chromosome number change. To date there have been 4,231 reported chromosome number counts in the family. Despite the large number of counts made, they only represent approximately 16% of the species currently recognized. These counts are here presented in an indexed list with standardized nomenclature following a draft copy of the World Checklist of Cyperaceae. Additionally, I explore variation within genera where a significant number of counts have been made. Given the distributions of counts within genera there is evidence for both agmatoploid and polyploid chromosome number changes.

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Chromosome Numbers and Dimensions, Species-Formation and Phylogeny in the Genus Carex

Cited by 90 publications

References 23 publications

Holokinetic centromeres and efficient telomere healing enable rapid karyotype evolution

Holokinetic centromeres and efficient telomere healing enable rapid karyotype evolution

The Evolution of Chromosome Arrangements in Carex (Cyperaceae)

A Synopsis of Chromosome Number Variation in the Cyperaceae

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