Chiasma redistribution in presence of supernumerary chromosome segments in grasshoppers: dependence on the size of the extra segment

Navas‐Castillo, Jesús; Cabrero, J.; Camacho, Juan Pedro M.

doi:10.1038/hdy.1987.69

Cited by 16 publications

(6 citation statements)

References 5 publications

(13 reference statements)

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“…The Bds1 segment polymorphism could be responsible for the chromosome length polymorphism observed in the different cytodemes (Houben et al 1999). The heterochromatin variation may play an indirect role in genome variation through its meiotic effects on chiasma distribution and frequency (Hewitt and John 1968;Jones and Rees 1982;Navas-Castillo et al 1987;Lopez-Leon et al 1992). One possibility is that the Bds1 tandem repeat sequence is a recent addition to the genome and homogenisation/stabilisation of the chromosome distribution may be expected later.…”

Section: Discussionmentioning

confidence: 99%

Cloning and characterisation of polymorphic heterochromatic segments of Brachycome dichromosomatica

Houben

Wanner²,

Hanson

et al. 2000

Chromosoma

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After selective enrichment and differential hybridisation of Cot-1 DNA fractions of plants with and without polymorphic heterochromatic segments, a repetitive sequence (called Bds1) specific to the polymorphic chromosome segments of Brachycome dichromosomatica (Brachyscome dichromosomatica) was isolated. A single repeat unit of Bds1 is 92 bp long and is organised in tandem arrays at three different polymorphic segment sites on the chromosomes of cytodeme A2. Although all three sites showed extensive polymorphism between plants, the karyotypes of all analysed mitotic root cells were stable within a single plant. Electron microscopy revealed heavily condensed chromatin structures at the most obvious polymorphic site. The mechanisms that generate and maintain the observed chromosome structure polymorphisms are discussed.

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Section: Discussionmentioning

confidence: 99%

Cloning and characterisation of polymorphic heterochromatic segments of Brachycome dichromosomatica

Houben

Wanner²,

Hanson

et al. 2000

Chromosoma

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“…Polymorphisms for extra segments (Camacho and Cabrero, 1982;Navas-Castillo et al, 1987) and B chromosomes (Henriques-Gil et al, 1984) are also frequent. The Leptysminae Cylindrotettix obscurus, C. santaroseae and Leptysma argentina have B chromosomes and, in the latter species, C-banding shows heterochromatin blocks in the centromeric regions of all chromosomes and in the interstitial regions of three medium pairs (Bidau and Hasson, 1984).…”

Section: A B D Cmentioning

confidence: 99%

Karyotype, constitutive heterochromatin and nucleolar organizer regions (NORs) in Belosacris coccineipes (Acrididae-Leptysminae)

Loreto

Souza

2000

Genet. Mol. Biol.

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Several techniques including C-banding, fluorochromes and silver staining were used to obtain information about heterochromatin patterns in the grasshopper B. coccineipes. Conventional staining showed a karyotype with 2n = 23 chromosomes in males and 2n = 24 in females, as well as XO:XX sex determination and acrotelocentric chromosomes. The medium-sized X chromosome was heteropycnotic positive at the beginning of prophase I and negative in metaphase I. C-banding revealed heterochromatic blocks in the pericentromeric regions of all chromosomes. Silver nitrate staining in this species showed three small bivalents (S9-S11) as nucleolar organizers with NORs located in the pericentromeric regions. CMA3-positive blocks were seen in pericentromeric regions of pairs M6, S9, S10 and S11. Sequential staining with CMA3/AgNO3 revealed homology between the CMA3-positive bands and NORs of the bivalents S9, S10 and S11. The CMA3-positive block of the bivalent M6 could represent a latent secondary NOR. The results obtained permit us to distinguish two categories of the constitutive heterochromatin in B. coccineipes.
Algumas técnicas incluindo bandeamento C, fluorocromos e coloração com nitrato de prata foram utilizadas visando obter informações sobre os padrões de heterocromatina no gafanhoto B. coccineipes. A análise convencional mostrou um cariótipo com 2n = 23 cromossomos nos machos e 2n = 24 nas fêmeas, sistema XO de determinação do sexo e cromossomos acro-telocêntricos. O cromossomo X de tamanho médio mostrou-se heteropicnótico positivo no início da prófase I e negativo em metáfase I. O bandeamento C revelou blocos positivos nas regiões pericentroméricas de todos os cromossomos. A coloração com nitrato de prata nesta espécie evidenciou 3 bivalentes pequenos (S9-S11) portadores de nucléolos com as NORs localizadas nas regiões pericentroméricas. Blocos CMA3-positivos foram visualizados nas regiões pericentroméricas dos pares M6, S9, S10 e S11. Pela coloração seqüencial CMA3/AgNO3 observamos homologia entre as bandas CMA3-positivas e as NORs dos bivalentes S9, S10 e S11. A marcação CMA3-positiva do bivalente M6 poderia representar uma NOR secundária latente. Os resultados obtidos permitiram distinguir duas categorias de heterocromatina constitutiva em B. coccineipes

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“…En todas las especies investigadas de Alstroemeria hasta el momento el polimorfismo de tamaño se ha observado probablemente en la condición heterocigótica; no habría indicación de polimorfismo en la condición homocigota. La naturaleza de esta diferencia de compactación de la cromatina reside presumiblemente en el origen de regiones heterocromáticas, como se documenta en Brachycome (Houben et al 2000), la que puede desempeñar un papel en la variación y el rearreglo del genoma en plantas (Jones & Rees 1982, Navas-Castillo et al 1987. Esta condición heterocigota representaría una ventaja selectiva para FIGURA 3.…”

Section: 3 (R Core Team 2017)unclassified

Polimorfismo de tamaño entre cromosomas homólogos, un caso extremo en Alstroemeria pulchra Sims. (Alstroemeriaceae), especie endémica de Chile

Baeza¹,

Toro²,

Ruíz³

et al. 2018

Gayana Bot.

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Alstroemeria pulchra is a Chilean species where 3 subspecies are recognized: subsp. lavandulacea, maxima and pulchra. The chromosomes of populations of the subspecies lavandulacea and pulchra were studied and a marked size polymorphism was observed among the homologous of the first pair of chromosomes. This size polymorphism among homologous is one of the rarest reported thus far in the Angiosperm literature.

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Chiasma redistribution in presence of supernumerary chromosome segments in grasshoppers: dependence on the size of the extra segment

Cited by 16 publications

References 5 publications

Cloning and characterisation of polymorphic heterochromatic segments of Brachycome dichromosomatica

Cloning and characterisation of polymorphic heterochromatic segments of Brachycome dichromosomatica

Karyotype, constitutive heterochromatin and nucleolar organizer regions (NORs) in Belosacris coccineipes (Acrididae-Leptysminae)

Polimorfismo de tamaño entre cromosomas homólogos, un caso extremo en Alstroemeria pulchra Sims. (Alstroemeriaceae), especie endémica de Chile

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