Heterochromatin diversity and its co-localization with 5S and 45S rDNA sites in chromosomes of four Maxillaria species (Orchidaceae)

Cabral, Juliano Sarmento; Félix, Leonardo P.; Guerra, Marcelo

doi:10.1590/s1415-47572006000400015

Cited by 65 publications

(51 citation statements)

References 33 publications

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“…Regarding the CMA ? /DAPI 0 bands, their restriction to the secondary constrictions, where the only ribosomal 45S loci mapped (see below), is in agreement with the pattern observed in different groups of plant species such as some orchids (Cabral et al 2006) and in species of the genus Cestrum (Fregonezi et al 2006). It is usually considered that these bands correspond to a proportion of the 45S rDNA genes (GC enriched) that remain condensed as heterochromatin within each loci (Schweizer 1976;Guerra 2000).…”

Section: Chromosome Bandingsupporting

confidence: 82%

Structural karyotypic variability and polyploidy in natural populations of the South American Lathyrus nervosus Lam. (Fabaceae)

et al. 2012

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Knowledge of the chromosome variation in wild populations is essential to understand the pathways and restrictions of karyotype evolution in plants. The aim of this study is to conduct an intraspecific analysis of the karyotypes by fluorochrome banding and ribosomal DNA (rDNA) loci detection by fluorescent in situ hybridization (FISH) and of the meiotic behaviour in natural populations of Lathyrus nervosus, sect. Notolathyrus. Chromosome banding showed that, despite the high constancy in the karyotype formula and in the rDNA loci among populations, there is intraspecific variation in the amount and distribution pattern of 4',6-diamidino-2-phenylindole (DAPI ? ) heterochromatin. However, those changes were not related to the total chromosome length of the haploid complements. This fact demonstrates that structural chromosome changes may be one of the most important mechanisms for karyotype variation among natural populations of L. nervosus. The chromosome number surveyed at the population level revealed the first case of polyploidy in South American species and the first case of uneven polyploidy of the genus. All the chromosome markers analysed indicated that the polyploids found originated by autopolyploidy. The meiotic analysis showed different chromosome abnormalities that may be generating numerical and structural changes in the sporads. The finding of unreduced gametes that are alive at anthesis suggests sexual polyploidization as the most probable mechanism involved in the origin of these 3x and 4x autopolyploid cytotypes in L. nervosus.

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Section: Chromosome Bandingsupporting

confidence: 82%

Structural karyotypic variability and polyploidy in natural populations of the South American Lathyrus nervosus Lam. (Fabaceae)

et al. 2012

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“…ex Lindl.) Ojeda & Carnevali (Cabral et al 2006;Epidendroideae, Maxillariinae), suggesting that the loss or acquisitions of this heterochromatin may be recurrent events in orchids. However, the occurrence of GC-rich heterochromatin on the terminal regions of all chromosomes in H .bicornis has not been reported for any other orchid species.…”

Section: Resultsmentioning

confidence: 99%

From Cuba to most of the neotropic: habenaria bicornis (orchidaceae) is widespread from Mexico to southeastern Brazil

Batista¹,

Proite²,

Carvalho³

et al. 2014

Lankesteriana

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Habenaria bicornis fue descrita por primera vez en 1835, para Cuba, y era conocida apenas para este país y unos pocos registros de Panamá, de 1920. En el presente estudio, demostramos que H. bicornis y H. goyazensis, esta última conocida para Brasil y Guiana, son específicas y la especie se distribuye desde México hasta el sudeste de Brasil. El modelado de nicho y la recolección de datos indican que esta especie posee una preferencia por sabanas húmedas de tierras bajas y es predicho que su distribución incluye gran parte del Neotrópico con hábitats favorables. Los análisis filogenéticos moleculares con secuencias del ADN nuclear (ITS) y plastidial (matK) ubicaron H. bicornis en una posición aislada próximo a la base del clado Neotropical, aunque con bajo soporte. En términos de su morfología, sus relaciones no están aclaradas, ya que no hay similitudes evidentes entre H. bicornis y los subclados básales o cualquier otro subclado Neotropical. Los análisis citogenéticos indican un número cromosómico básico de x=21, similar a las otras especies basales del Neotrópico.

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“…Root tips were digested using a solution containing 2% cellulase and 20% pectinase (w/v) for 90 min at 37°C, and the meristem dissected in 45% (v/v) aqueous acetic acid, squashed under a cover slip (subsequently removed by freezing in liquid nitrogen), airdried and then aged for 3 days. Selection of slides, CMA/ DAPI staining, and destaining for FISH were performed according to Cabral et al (2006).…”

Section: Chromosome Preparation and Fluorochrome Stainingmentioning

confidence: 99%

Comparative cytogenetic mapping between the lima bean (Phaseolus lunatus L.) and the common bean (P. vulgaris L.)

et al. 2012

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The common bean (Phaseolus vulgaris) and lima bean (P. lunatus) are among the most important legumes in terms of direct human consumption. The present work establishes a comparative cytogenetic map of P. lunatus, using previously mapped markers from P. vulgaris, in association with analyses of heterochromatin distribution using the fluorochromes chromomycin A3 (CMA) and 4',6-diamidino-2-phenylindole (DAPI) and localization of the 5S and 45S ribosomal DNA (rDNA) probes. Seven BACs selected from different common bean chromosomes demonstrated a repetitive pericentromeric pattern corresponding to the heterochromatic regions revealed by CMA/DAPI and could not be mapped. The subtelomeric repetitive pattern observed for BAC 63H6 in most of the chromosome ends of common bean was not detected in lima bean, indicating lack of conservation of this subtelomeric repeat. All chromosomes could be identified and 16 single-copy clones were mapped. These results showed a significant conservation of synteny between species, although change in centromere position suggested the occurrence of pericentric inversions on chromosomes 2, 9 and 10. The low number of structural rearrangements reflects the karyotypic stability of the genus.

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Heterochromatin diversity and its co-localization with 5S and 45S rDNA sites in chromosomes of four Maxillaria species (Orchidaceae)

Cited by 65 publications

References 33 publications

Structural karyotypic variability and polyploidy in natural populations of the South American Lathyrus nervosus Lam. (Fabaceae)

Structural karyotypic variability and polyploidy in natural populations of the South American Lathyrus nervosus Lam. (Fabaceae)

From Cuba to most of the neotropic: habenaria bicornis (orchidaceae) is widespread from Mexico to southeastern Brazil

Comparative cytogenetic mapping between the lima bean (Phaseolus lunatus L.) and the common bean (P. vulgaris L.)

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