DNA structure of the B chromosome of rye revealed by in situ hybridization using repetitive sequences.

Tsujimoto, Hisashi; Niwa, Katsumasa

doi:10.1266/jjg.67.233

Cited by 32 publications

(20 citation statements)

References 15 publications

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“…structure of the B chromosome in Z. sylvatica. In Secale cereale the genomic structure of supernumerary chromosomes, studied with in situ hybridization suggested that they were formed partially by a similar genome of the A chromosomes, besides specific terminal heterocromatin B (Tsujimoto & Niwa 1992). These chromosomes were positively associated with genome size, especially in dicots, and slightly negatively associated with ploidy level (Trivers et al 2004).…”

Section: Resultsmentioning

confidence: 98%

Intrapopulational chromosome number variation in Zephyranthes sylvatica Baker (Amaryllidaceae: Hippeastreae) from Northeast Brazil

Felix¹,

Dutilh²,

Melo³

et al. 2008

Rev. bras. Bot.

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-(Intrapopulational chromosome number variation in Zephyranthes sylvatica Baker (Amaryllidaceae: Hippeastreae) from Northeast Brazil). Zephyranthes Herb. is a taxonomically complex and cytologically variable group, with about 65 species of Neotropical distribution. Chromosome number variability in 32 individuals of a Zephyranthes sylvatica population from Northeast Brazil was investigated. Three cytotypes were found: 2n = 12 (one metacentric, four submetacentric and one acrocentric pairs), in 24 individuals; 2n = 12 + 1B, in five and three individuals with 2n = 18, a triploid cytotype. All diploid individuals showed chromosomes with polymorphism in pair one and two, while in triploids this polymorphism was observed in all chromosome triplets, generally with two homomorphic chromosomes and a higher or lower heteromorphic chromosome. All individuals had reticulated interfasic nucleus and a slightly asymmetric chromosome complement, with one metacentric chromosome pair and the others more submetacentric to acrocentric. These data confirm the cytological variability previously registered for the genus. Mechanisms involved in karyotypic evolution in this population are discussed.Key words -Amaryllidaceae, B chromosomes, chromosome variability, triploid, Zephyranthes RESUMO -(Variação cromossômica numérica intrapopulacional em Zephyranthes sylvatica Baker (Amaryllidaceae: Hippeastreae) no Nordeste do Brasil). O gênero Zephyranthes Herb. é um grupo taxonômicamente complexo e cariologicamente variável, compreende cerca de 65 espécies de distribuição predominantemente neotropical. O presente trabalho aborda a variabilidade cariológica em um total de 32 indivíduos de Z. sylvatica obtidas em uma única população do Nordeste do Brasil. Todos os indivíduos apresentaram núcleo interfásico reticulado e complemento cromossômico bimodal, pela ocorrência de um par cromossômico metacêntrico e os demais submetacêntricos. Foram observados três citotipos: 2n = 12 (um par metacêntrico, quatro submetacêntricos e um acrocêntricos) em 24 indivíduos; 2n = 12 + 1B, em cinco, além de um citotipo triplóide com 2n = 18 em três indivíduos. Todos os citotipos diplóides exibiram polimorfismo cromossômico para os pares um e dois, enquanto nos triplóides esse mesmo polimorfismo foi observado nas trincas correspondente aos pares cromossômicos diplóides, geralmente com dois cromossomos homórficos e um cromossomo heteromórfico maior que os dois anteriores. Esses dados confirmam a variabilidade cariológica anteriormente registrada para o gênero. São discutidos os mecanismos de evolução cariotípica envolvidos nessa variabilidade.

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Section: Resultsmentioning

confidence: 98%

Intrapopulational chromosome number variation in Zephyranthes sylvatica Baker (Amaryllidaceae: Hippeastreae) from Northeast Brazil

Felix¹,

Dutilh²,

Melo³

et al. 2008

Rev. bras. Bot.

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“…The in situ hybridization was carried out as described previously (Tsujimoto and Niwa, 1992) with some modifications: After removal of the cover slips by the dry ice method, the slides bearing chromosomes were immersed in 45% acetic acid at room temperature for 5 min followed by air drying and denaturation of chromosomal DNA by incubating the specimens in 70% formamide-2 × SSC for 2 min. Treatment with streptavidin-horse-radish peroxidase complex was prolonged to 45 min and detection with DAB to 30 min.…”

Section: Methodsmentioning

confidence: 99%

Identification of individual barley chromosomes based on repetitive sequences: Conservative distribution of Afa-family repetitive sequences on the chromosomes of barley and wheat.

et al. 1997

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The Afa-family repetitive sequences were isolated from barley (Hordeum vulgare, 2n = 14) and cloned as pHvA14. This sequence distinguished each barley chromosome by in situ hybridization. Double color fluorescence in situ hybridization using pHvA14 and 5S rDNA or HvRT-family sequence (subtelomeric sequence of barley) allocated individual barley chromosomes showing a specific pattern of pHvA14 to chromosome 1H to 7H. As the case of the D genome chromosomes of Aegilops squarrosa and common wheat (Triticum aestivum) hybridized by its Afa-family sequences, the signals of pHvA14 in barley chromosomes tended to appear in the distal regions that do not carry many chromosome band markers. In the telomeric regions these signals always placed in more proximal portions than those of HvRTfamily. Based on the distribution patterns of Afa-family sequences in the chromosomes of barley and D genome chromosomes of wheat, we discuss a possible mechanism of amplification of the repetitive sequences during the evolution of Triticeae. In addition, we show here that HvRT-family also could be used to distinguish individual barley chromosomes from the patterns of in situ hybridization.

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“…In terms of structural organization, the rye B is mainly composed of DNA sequences in common with those of the A chromosomes (As) (Rimpau and Flavell, 1975;Timmis et al, 1975), with the exception of the terminal part of the long arm (Tsujimoto and Niwa, 1992;Wilkes et al, 1995;Houben et al, 1996). Two B-specific families of high-copy repetitive DNA, D1100 (Sandery et al, 1990) and E3900 (Blunden et al, 1993), have been isolated and mapped to this terminal domain.…”

Section: Introductionmentioning

confidence: 99%

Transcriptionally Active Heterochromatin in Rye B Chromosomes

et al. 2007

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B chromosomes (Bs) are dispensable components of the genomes of numerous species. Thus far, there is a lack of evidence for any transcripts of Bs in plants, with the exception of some rDNA sequences. Here, we show that the Giemsa banding-positive heterochromatic subterminal domain of rye (Secale cereale) Bs undergoes decondensation during interphase. Contrary to the heterochromatic regions of A chromosomes, this domain is simultaneously marked by trimethylated H3K4 and by trimethylated H3K27, an unusual combination of apparently conflicting histone modifications. Notably, both types of B-specific high copy repeat families (E3900 and D1100) of the subterminal domain are transcriptionally active, although with different tissue type–dependent activity. No small RNAs were detected specifically for the presence of Bs. The lack of any significant open reading frame and the highly heterogeneous size of mainly polyadenylated transcripts indicate that the noncoding RNA may function as structural or catalytic RNA.

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DNA structure of the B chromosome of rye revealed by in situ hybridization using repetitive sequences.

Cited by 32 publications

References 15 publications

Intrapopulational chromosome number variation in Zephyranthes sylvatica Baker (Amaryllidaceae: Hippeastreae) from Northeast Brazil

Intrapopulational chromosome number variation in Zephyranthes sylvatica Baker (Amaryllidaceae: Hippeastreae) from Northeast Brazil

Identification of individual barley chromosomes based on repetitive sequences: Conservative distribution of Afa-family repetitive sequences on the chromosomes of barley and wheat.

Transcriptionally Active Heterochromatin in Rye B Chromosomes

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