Indian Society of Genetics & Plant Breeding

DESYNAPSIS AND SPONTANEOUS CHROMOSOME BREAKAGE IN SORGHUM PURPUREO-SERICEUM

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SEVERAL types of deviation from regular pairing of chromosomes have been recorded
in literature and one of the most interesting among these is de3ynapsis. The distinction between desynapsis and asynapis appears clear enough in theory (Li
et al., 1945)
but is not so clear cut in practice. The term desynapsis is usually applied when
homologous chromosomes pair normally at pachytene but begin to fall apart at diplotene and are often completely unpaired at diakinesis and metaphase I. In asynapsis,
on the other hand, pairing between homologous chromosomes ntver occurs. The
major difficulty in differentiating these two phenomena in practice is that in a large
number of species pachytene stages are not amenable for thorough analysis. However, in those species where pachytene stages of " asynaptics" have been critically
examined, pairing of homologous chromosomes has been shown to occur at this stage and
hence it has been suggested (Celarier, 1955) that asynapsis may, in fact, not exist.
  

Info

Year: 1961
Volume: 21
Issue: 2
Article DOI: NA
Print ISSN: 0019-5200
Online ISSN: 0975-6906

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