منابع مشابه
Nondisjunction in favor of a chromosome: the mechanism of rye B chromosome drive during pollen mitosis.
B chromosomes (Bs) are supernumerary components of the genome and do not confer any advantages on the organisms that harbor them. The maintenance of Bs in natural populations is possible by their transmission at higher than Mendelian frequencies. Although drive is the key for understanding B chromosomes, the mechanism is largely unknown. We provide direct insights into the cellular mechanism of...
متن کاملTranscriptionally active heterochromatin in rye B chromosomes.
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...
متن کاملSubstitution of rye chromosome 5r for chromosome 5b of wheat and its effect on chromosome pairing.
HEXAPLOID wheat normally exhibits homologous pairing, forming only bivalents at meiosis. However, in the absence of chromosome 5B, homoeologous as well as homologous pairing occurs ( SEARS and OKAMOTO 1958; RILEY and CHAPMAN 1958; RILEY and KEMPANNA 1963). In 5Bdeficient hybrids between wheat and related genera, the level of chromosome pairing is increaesd (RILEY, CHAPMAN and KIMBER 1959). In w...
متن کاملDe novo evolution of satellite DNA on the rye B chromosome.
The most distinctive region of the rye B chromosome is a subtelomeric domain that contains an exceptional concentration of B-chromosome-specific sequences. At metaphase this domain appears to be the physical counterpart of the subtelomeric heterochromatic regions present on standard rye chromosomes, but its conformation at interphase is less condensed. In this report we show that the two sequen...
متن کاملChromosome pairing in tetraploid rye with monosomic-substitution wheat chromosomes.
In tetraploid rye with single-substitution wheat chromosomes - 1A, 2A, 5A, 6A, 7A, 3B, 5B, 7B - chromosome pairing was analysed at metaphase I in PMCs with the C-banding method. The frequency of univalents of chromosome 1A was considerably higher than that of the other four wheat chromosomes of genome A (6A, 5A, 7A and 2A). Among chromosomes of genome B, the lowest mean frequency of univalents ...
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ژورنال
عنوان ژورنال: Heredity
سال: 1978
ISSN: 0018-067X,1365-2540
DOI: 10.1038/hdy.1978.62