Ultrastructural analysis of meiotic recombination and chiasma formation.
Tokai J Exp Clin Med
; 11(6): 415-36, 1986 Dec.
Article
in En
| MEDLINE
| ID: mdl-3328325
ABSTRACT
Meiotic recombination appears to be mediated by recombination nodules, small electron dense spheres, associated with the central region of the synaptonemal complex. These structures are a prerequisite for, not the result of crossing over and they undergo complex structural, numerical and distributional changes before the final distribution of crossovers is achieved. In the organisms studied the nodules are placed randomly along and among the bivalents at zygotene. Subsequently, the distribution is modified to insure that each bivalent and generally each bivalent arm attain a nodule and that close spacing of nodules is minimized. Analysis of the number and location of recombination nodules at pachytene provides knowledge of the number and physical distribution of crossovers in the individual bivalents. Chiasmata originate from recombination nodules. At early diplotene the chiasma consists of a retained segment of synaptonemal complex containing a derivative of a recombination nodule. At late meiotic prophase the segment is eliminated after the formation of a chromatin chiasma.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Chromosomes
/
Meiosis
Type of study:
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
Tokai J Exp Clin Med
Year:
1986
Document type:
Article
Affiliation country:
Denmark