Karyotype evolution by centromeric fission inZamia (Cycadales)

Moretti, Aldo; Sabato, Sergio

doi:10.1007/bf00989547

Cited by 41 publications

(24 citation statements)

References 4 publications

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“…Renewed interest in cycads has resulted in work being done on toxicity, population ecology, phytochemistry, cytotaxonomy, and ecophysiology (De Luca & al., 1982;Newell, 1983;Vovides, 1983Vovides, , 1985Vovides, , 1990Moretti & Sabato, 1984;Clark & Clark, 1988;Moretti, 1990;Charlton & al., 1992;Donaldson, 1995;Kokubugata & Kondo, 1996Vovides & Olivares, 1996;Pérez-Farrera & al., 2000;. With regard to secondary products, certain toxins are peculiar only to cycads, such as cycasin.…”

Section: Introductionmentioning

confidence: 99%

A review of research on the cycad genus Ceratozamia Brongn. (Zamiaceae) in Mexico

Vovides

González

Pérez‐Farrera

et al. 2004

TAXON

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The genus Ceratozamia contains more than 20 species distributed in eastern and southern Mexico, with extensions into Central America. Morphology, anatomy, and molecular (ITS) data allow resolution of some aspects of species relationships, provide correlations with ecology, and suggest phytogeographic hypotheses. Some species complexes, such as those centered around C. norstogii and C. miqueliana, are restricted to southernwest Mexico, in what are regarded as Pleistocene floristic refugia. The low level of divergence of ITS sequences among taxa to the north of the Trans–Mexican Neovolcanic mountain range suggests a pattern of recent, and perhaps rapid, speciation.

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Section: Introductionmentioning

confidence: 99%

A review of research on the cycad genus Ceratozamia Brongn. (Zamiaceae) in Mexico

Vovides

González

Pérez‐Farrera

et al. 2004

TAXON

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“…Chromosomal fission decreases genetic hitchhiking by severing transcentromeric linkages, allowing for direct selection on newly unlinked genes (Todd, 1970; Levin, 2000). High chromosome numbers in Zamia have been correlated with morphological variability and stressful or widely variable habitats (Moretti & Sabato, 1984; Moretti et al ., 1991; Caputo et al ., 1996; Vovides & Olivares, 1996; Napolitano et al ., 2004). Moretti & Sabato (1984) speculated that stressful habitats might cause chromosomal fission, allowing species to invade and survive in a wider habitat range than their relatives with lower chromosome numbers.…”

Section: Discussionmentioning

confidence: 99%

Chromosomal fission accounts for small-scale radiations in Zamia (Zamiaceae; Cycadales)

Olson¹,

Gorelick²

2011

Botanical Journal of the Linnean Society

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Zamia is unique among Cycadales in its diversity of morphology, ecology and chromosome numbers. The chromosome numbers in Zamia range from 16 to 28, excluding 20, manifest as both interspecific and intraspecific series. It has long been recognized that Robertsonian transformations (chromosomal fission or fusion) probably dominate karyotype evolution in Zamiaceae, although it has been debated whether chromosome numbers are increasing or decreasing. We re-analyse published karyotypes of Zamia spp., relating both chromosome forms and sizes to recent phylogenetic data. We show that karyotype evolution is most probably moving towards increased asymmetry, with higher numbers of smaller chromosomes, thus supporting chromosomal fission. We also address additional hypotheses for increasing chromosome numbers, namely pericentric inversions and unequal translocations. Finally, we discuss the role of these chromosomal changes in evolutionary radiations.

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“…Typically, the repeat DNA organization and its chromosome distribution are related to genome evolution (Charlesworth et al 1994, Fuchs et al 1995, Lin et al 2005) and the scattered presence in the Zamia genome of these dispersed repeated elements that contain satellite repeat arrays could be involved in the unusual karyotype variations observed in this plant group. In this regard, if centric fission is accepted as the main cause of chromosomal changes in Zamia (Moretti and Sabato 1984), such a type of occurrence of repeated sequences scattered along the chromosomes, producing many areas of sequence homology in different chromosomes, could influence correct chromosome pairing and promote chromosome rearrangements.…”

Section: Discussionmentioning

confidence: 99%

“…Zamia is also unique among cycads in showing interspecific and intraspecific karyotype variation (Marchant 1968, Norstog 1980, Moretti 1990a. Occurrence of Robertsonian changes, such as centric fission of metacentric chromosome or centric fusion of telocentric chromosomes, has been suggested to explain the causes of the high chromosome variability reported in Zamia (Norstog 1980, Moretti and Sabato 1984, Schutzman et al 1988, Moretti 1990b, Moretti et al 1991.…”

Section: Introductionmentioning

confidence: 99%

Organization of a dispersed repeated DNA element in the Zamia genome

Cafasso¹,

Cozzolino²,

Vereecken³

et al. 2009

Biol. plant.

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Occurrence and genomic organization of dispersed elements containing ZpS1 satellite repeats have been investigated in a wide representation of species of the old plant genus Zamia (Zamiaceae, Cycadales). In Z. paucijuga, the ZpS1 repeat is organized as long satellite DNA arrays and as short arrays inserted into AT-rich dispersed elements. A comparative study by Southern analysis shows that these unusual dispersed elements containing the ZpS1 repeat are present with different organizations in all investigated Zamia species. In some species these elements are present with a low copy number, while in other species secondary amplification events, involving specific sequence clusters, appear to have generated characteristic dispersed elements in a high copy number. Among Zamia species, several groups share similar restriction patterns, as the Zamia loddigesii complex and the Caribbean species suggesting a general correlation between organization and genomic representation of the dispersed repeated sequence and the pattern of phyletic relationships in the genus. However, the finding of different patterns also among closely related species suggests a complex history of amplifications and losses of these dispersed repetitive elements that cannot be always easily traced through the phylogenetic reconstruction of this ancient plant group.

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Karyotype evolution by centromeric fission inZamia (Cycadales)

Cited by 41 publications

References 4 publications

A review of research on the cycad genus Ceratozamia Brongn. (Zamiaceae) in Mexico

A review of research on the cycad genus Ceratozamia Brongn. (Zamiaceae) in Mexico

Chromosomal fission accounts for small-scale radiations in Zamia (Zamiaceae; Cycadales)

Organization of a dispersed repeated DNA element in the Zamia genome

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