Heterochromatin differentiation in holocentric chromosomes of Rhynchospora (Cyperaceae)
نویسندگان
چکیده
منابع مشابه
Localization of 45S rDNA and telomeric sites on holocentric chromosomes of Rhynchospora tenuis Link (Cyperaceae)
Rhynchospora tenuis Link (Cyperaceae) is a weed widely distributed in Brazil that presents a small number of holocentric chromosomes (2n = 4) with some autopolyploid populations (2n = 8). The haploid number n = 2 is considered as a derivative of the base number x = 5. 45S rDNA probes and telomeric DNA were hybridized in both chromosome races of R. tenuis, looking for indications of chromosome f...
متن کاملDevelopmental programmed cell death during asymmetric microsporogenesis in holocentric species of Rhynchospora (Cyperaceae)
Members of the Cyperaceae family exhibit an asymmetric microsporogenesis that results in the degeneration of three out of four meiotic products. Efforts have been made previously to describe the resulting structure, named the pseudomonad, but mechanisms concerning the establishment of cell domains, nuclear development, and programmed cell death are largely unknown. Using the Rhynchospora genus ...
متن کاملHeterochromatin base pair composition and diversification in holocentric chromosomes of kissing bugs (Hemiptera, Reduviidae)
The subfamily Triatominae (Hemiptera, Reduviidae) includes 150 species of blood-sucking insects, vectors of Chagas disease or American trypanosomiasis. Karyotypic information reveals a striking stability in the number of autosomes. However, this group shows substantial variability in genome size, the amount and distribution of C-heterochromatin, and the chromosome positions of 45S rDNA clusters...
متن کاملRestructuring of Holocentric Centromeres During Meiosis in the Plant Rhynchospora pubera.
Centromeres are responsible for the correct segregation of chromosomes during mitosis and meiosis. Holocentric chromosomes, characterized by multiple centromere units along each chromatid, have particular adaptations to ensure regular disjunction during meiosis. Here we show by detecting CENH3, CENP-C, tubulin, and centromeric repeats that holocentromeres may be organized differently in mitosis...
متن کاملEvidence for Centromere Drive in the Holocentric Chromosomes of Caenorhabditis
In monocentric organisms with asymmetric meiosis, the kinetochore proteins, such as CENH3 and CENP-C, evolve adaptively to counterbalance the deleterious effects of centromere drive, which is caused by the expansion of centromeric satellite repeats. The selection regimes that act on CENH3 and CENP-C genes have not been analyzed in organisms with holocentric chromosomes, although holocentrism is...
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ژورنال
عنوان ژورنال: Genetics and Molecular Biology
سال: 2000
ISSN: 1415-4757
DOI: 10.1590/s1415-47572000000200034