The recombination nodule story ? seeing what you are looking at

BioEssays ◽  
1994 ◽  
Vol 16 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Adelaide T. C. Carpenter
Keyword(s):  

Genetics ◽  
1979 ◽  
Vol 92 (2) ◽  
pp. 511-541
Author(s):  
Adelaide T C Carpenter

ABSTRACT Electron microscope serial section reconstruction analysis of all zygotene-pachytene nuclei of meiotic cells from three wild-type germaria (a subunit of the ovary containing the early meiotic stages arrayed in temporal developmental sequence) of Drosophila melanogaster females corroborates and extends earlier observations (CARPENTER 1975a) on the nature and sequence of ultrastructural events occurring during the time of meiotic recombination. Emphasis has been placed on (1) the time of appearance and disappearance of the synaptonemal complex (SC) and the changes in its dimensions that accompany a cell's progression through pachytene, and (2) the appearance, disappearance, number and chromosomal locations of recombination nodules (CARPENTER 1975b). For both the SC and the recombination nodule the availability of several developmental series has provided an estimate of the biological variability in the properties of these recombination-associated structures. The much more extensive data presented here substantiate the earlier hypothesis that recombination nodules occur at sites where reciprocal meiotic recombination will occur, has occurred, or is occurring. A second morphological type of recombination nodule is reported; it is suggested that the presence of the latter type of nodule may correlate with sites of gene conversion. The hypothesis that there may be two types of meiotic recombination processes is discussed.



2015 ◽  
Author(s):  
Cathleen M Lake ◽  
Rachel J Nielsen ◽  
Fengli Guo ◽  
Jay R Unruh ◽  
Brian D Slaughter ◽  
...  


Genome ◽  
1999 ◽  
Vol 42 (2) ◽  
pp. 308-314 ◽  
Author(s):  
M.I. Pigozzi ◽  
A.J. Solari


1988 ◽  
Vol 48 (3) ◽  
pp. 130-136 ◽  
Author(s):  
A.J. Solari ◽  
N.S. Fechheimer ◽  
J.J. Bitgood
Keyword(s):  


Genome ◽  
1988 ◽  
Vol 30 (6) ◽  
pp. 900-902 ◽  
Author(s):  
A. J. Solari ◽  
N. S. Fechheimer

Synaptonemal complex analysis of an exceptional tetraploid oocyte from a diploid chicken heterozygous for the MN t (Z;1) rearrangement was performed by electron microscopy of a spread preparation. Ten separate quadrivalents (26% of the chromosomal axes) were analyzed, as well as 50 autosomal bivalents. All the axes less than 2.5 μm in length formed bivalents (38) only, while axes in the 2.5–4.2 μm range formed 5 quadrivalents and 12 bivalents. The longer, separate axes formed quadrivalents only. Partner switches in excess of one were documented. The two identical W chromosomes paired only at the ends of their short arms. Quadrivalent formation may require a threshold length (2.5 μm), at least in this species. The tip of the short arm of the W chromosome may be a pairing initiation point, and it corresponds to the region associated with a localized recombination nodule previously described in diploid oocytes.Key words: quadrivalent, tetraploid, synaptonemal complex, chicken oocyte.



Genome ◽  
1991 ◽  
Vol 34 (5) ◽  
pp. 718-726 ◽  
Author(s):  
Alberto J. Solari ◽  
M. H. Thorne ◽  
B. L. Sheldon ◽  
C. B. Gillies

Twelve triploid, ZZW chickens of ages ranging from day 19 of incubation to 15 days after hatching were used for oocyte analysis. Oocytes show 117 axes per nucleus. At early pachytene, most axes form double synaptonemal complexes (triplets). An average of 27 triplets, 12 bivalents, and 12 univalents was observed. Later, a partial elimination of triplets occurs, as they are converted into typical trivalents or bivalents and univalents. The number of recombination nodules per nucleus (52.7) is similar to that of diploids. These nodules can occur in register in both central regions of a triplet (no lateral interference), and they probably stabilize the central region. Among 31 oocytes, 29 had a regular ZZ bivalent and a W univalent, and only 2 had triple pairing between a ZZ bivalent and a terminal region of the W axis (less than 1 μm in length and having a terminal recombination nodule). Competition for pairing between the gonosomes results in a large (93.5% of cases) predominance of Z–Z pairing, because of a relatively minor homology between the W and Z chromosomes. The prevailing pairing failure of the W chromosome may lead to early oocyte loss.Key words: sex chromosomes, triploids, synaptonemal complex, Z–W pairing, chicken, recombination nodules.



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