DNA Synthesis During Microsporogenesis
Meiosis is a major and critical event in microsporogenesis. In the course of that event, the processes of pairing and crossing-over activate elements of chromosome organization that are probably not required for vegetative growth and reproduction. Even where mitotic crossing over does occur, its frequency is rare presumably because a supportive organization is lacking. An apparently loose form of pairing between homologous chromosomes has been reported for somatic cells of various plant species (4), but such “somatic association” is both morphologically and functionally distinct from meiotic pairing and its accompanying exchange. The latter are virtually unique to meiocytes. Although the regulation of chromosome reproduction and transcription imposes broad requirements on chromosome organization, it is doubtful that such organization encompasses the special needs of chromosomes in meiosis. The major thrust of this presentation is to demonstrate that there are indeed components of chromosome organization which, thus far at least, have been revealed only during meiosis. Two of these components are expressed in the sequence organization of DNA and thus are fixed characteristics of the linear differentiation of the chromosome (4).
KeywordsChromosome Pairing Meiotic Prophase Chromosome Organization Chromatin Compaction Sedimentation Profile
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