The pachytene karyotype of Schizophyllum commune analyzed by three dimensional reconstruction of synaptonemal complexes

Carmi, Pheya; Holm, Preben Bach; Koltin, Y.; Rasmussen, Søren W.; Sage, Jean; Zickler, Denise

doi:10.1007/bf02906508

Cited by 45 publications

(21 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This study recorded a 1 .8x range of SC lengths among pachytene oocytes and also concluded that SC lengths initially decreased during early to mid pachytene before extending again during late pachytene. A similar pattern of change in SC length was described in hamster spermatocytes, where sub-stages of pachytene Carmi et al (1978) were defined by changes in XY morphology (Moses et a!., 1977 (Gillies, 1983). The ranges of SC lengths observed in Crepis capillaris are similar to those described in maize which supports the contention that the pachytene nuclei analysed in the present study represent the entire range of pachytene.…”

Section: Introductionsupporting

confidence: 55%

Inter- and intra-plant SC length variation in Crepis capillaris

Azkue

Jones

1993

Heredity

View full text Add to dashboard Cite

Synaptonemal complexes (SCs) were measured in large samples (16-31) of pachytene nuclei from five different plants of Crepis capillaris, with the aim of conducting a systematic study of intra-plant and interplant SC length variation. Individual plants showed considerable variation in SC length among cells (average range= 1.83x), which is presumed to reflect stage-related differences in chromosome and SC length during pachytene. The five plants selected for study showed highly significant differences in SC length. These differences are interpreted as real differences in the means and ranges of SC lengths in different genotypes rather than, for example, sampling effects. Mean SC lengths at pachytene and mean chiasma frequencies at metaphase I show signs of being positively related, but the correlation is statistically non-significant, indicating a need for more extensive study.

show abstract

Section: Introductionsupporting

confidence: 55%

Inter- and intra-plant SC length variation in Crepis capillaris

Azkue

Jones

1993

Heredity

View full text Add to dashboard Cite

show abstract

“…These studies have shown that at pachytene, homologous chromosomes are held in register by a continuous synaptonemal complex from telomere to telomere revealing an apparently specific site-to-site matching of homologous regions. Both light and electron microscopical studies agree in that the number of irregularities is surprisingly low (2,4,6,9,13,14,16,22,33). Furthermore, it has been demonstrated that prior to the onset of pairing, homologous chromosomes are either located at random in the nucleus (1 i, 12, 22, 25) or in separate nuclei (4, 0105-1938/79/0044/0101/$ 05.00 32, 33) the only exception being organisms with a permanent somatic pairing of homologous chromosomes.…”

Section: Introductionmentioning

confidence: 70%

Chromosome pairing in autotetraploid Bombyx females. Mechanism for exclusive bivalent formation

Rasmussen

Holm

1979

Carlsberg Res. Commun.

Self Cite

View full text Add to dashboard Cite

Meiosis in tetraploid Bombyx mori oocytes has been analyzed by three dimensional reconstructions of 1 mid zygotene, 7 early pachytene and 11 mid-late pachytene nuclei. The general pattern of chromosome pairing was found to be essentially similar to that of diploid oocytes. The zygotene stage is recognizable by incomplete pairing and a distinct chromosome bouquet, early pachytene by complete or almost complete pairing and a distinct bouquet and mid-late pachytene by dissolution of the bouquet followed by release of chromosome ends from their attachment sites on the nuclear envelope. At early pachytene the nuclei contained 5-12 quadrivalents, 0-7 univalents, 0-3 trivalents and 27-44 bivalents. The corresponding figures for mid-late pachytene were 0-2 quadrivalents, 0-3 univalents, 0-2 trivalents and 48-56 bivalents. The remarkable decrease in the number of quadrivalents and the corresponding increase in the number of bivalents between early and mid-late pachytene is the result of a correction of the zygotene pairing. In the absence of crossing over and chiasma formation, the pairing of the randomly located leptotene chromosomes into the maximal number of bivalents consists thus of two phases: 1) A specific zygotene pairing with synaptonemal complex formation restricted to homologous chromosome regions and 2) a correction of irregularities in this pairing by partial, dissolution of the central region of the complex succeeded by or coinciding with a second round of synaptonemal complex formation, permitting also nonhomologous pairing. It is suggested that in organisms with crossing over and chiasma formation the correction process is impeded by the occurrence of crossovers.

show abstract

“…It is the impression, however, that nodules at early pachytene are larger, denser and more frequently positioned adjacent to the central region of the complex than those of early zygotene nuclei. Comparable intranuclear variation in the morphology of the nodules has been described in Ascomycetes and Basidiomycetes (3,15,53). In Neurospora, for example, the length of the nodules ranges from 55 to 210 nm and the width from 20 to 90 nm.…”

Section: Morphologymentioning

confidence: 81%

“…The material consists of biopsies from three normal fertile men undergoing vasectomy. A detailed description of the mid-late pachytene stage in the spermatocytes of these men has been presented in a previous publication (cases [3][4][5]20). In addition, a testicular biopsy from a man carrying a balanced translocation was analyzed.…”

Section: Methodsmentioning

confidence: 99%

“…These models provide a simple explanation for the sometimes overlooked but important feature of homologous chromosomes, namely that they are always of the same length whether they are completely paired with a synaptonemal complex, present as partially paired bivalents, or even as univalents (19,42,53). The internuclear variation in the length of a given chromosome which is common in most organisms (3,12,15,20,40,53) is thus not reflected by a comparable variation in the intranuclear lengths of the two homologues.…”

Section: Correction Of Interlockingmentioning

confidence: 99%

See 1 more Smart Citation

Human meiosis II. Chromosome pairing and recombination nodules in human spermatocytes

Rasmussen

Holm

1978

Carlsberg Res. Commun.

Self Cite

146

161

View full text Add to dashboard Cite

Meiosis in human spermatocytes has been analyzed by three dimensional reconstructions of 4 leptotene, 4 earlymid zygotene, 10 late zygotene, and 21 early pachytene nuclei. At leptotene, a lateral component is organized along each chromosome and the telomeres attach to the nuclear envelope. At early zygotene, the attachment sites aggregate and a chromosome bouquet is formed. Pairing and synaptonemal complex formation are initiated from the telomeres by binding of precursor material for the central region to the lateral components of the aligned homologues. In the 10 late zygotene nuclei, on the average 72% of the autosomal complement had been paired. Synaptonemal complex formation is in most cases initiated from both ends of the homologues and only in 5 cases was initiation of complex formation interstitial. Pairing of the short arms of the acrocentric bivalents and the X and Y chromosomes is delayed compared to the remainder of the genome. Irregularities such as interlockings and breaks of the lateral components of chromosomes or breaks of the synaptonemal complexes of bivalents are observed in 8 out of the 10 nuclei. Most of the breaks appeared to be the result of a resolution of interlockings. At early pachytene, all bivalents are fully paired the only exception being the secondary constrictions on bivalents 1 and 9 which frequently remain unpaired. In all nuclei, a short stretch of synaptonemal complex is present between the X and Y chromosomes. Only two interlockings and three breaks of lateral components of chromosomes were found at this stage. Recombination nodules are present in or at the central region of the synaptonemal complex from early zygotene and evidence has been obtained in favor of an attachment of nodules to precursor material for the central region at the pairing fork. Nodules can, however, also attach to a fully formed synaptonemal complex. At late zygotene, an average number of 101 nodules per nucleus is present. Assuming that all regions of the complex have equal probabilities of receiving a nodule about 144 nodules are expected to be present at the moment of complete pairing. At early pachytene, the mean number of nodules is 75. Generally, nodules appear to be distributed evenly along the bivalent arms. Nodules are present, however, in excess in the telomere regions and in the XY bivalent while the centromere regions, the secondary constrictions, and the short arms of the acroeentric bivalents are relatively depleted of nodules. Measurements of the distances between adjacent nodules and a comparison with a theoretical distribution of such distances assuming a random positioning of nodules have demonstrated that at late zygotene nodules are more frequently clustered than would be expected if they were distributed independently. At early pachytene, the reverse pattern is observed.

show abstract

The pachytene karyotype of Schizophyllum commune analyzed by three dimensional reconstruction of synaptonemal complexes

Cited by 45 publications

References 26 publications

Inter- and intra-plant SC length variation in Crepis capillaris

Inter- and intra-plant SC length variation in Crepis capillaris

Chromosome pairing in autotetraploid Bombyx females. Mechanism for exclusive bivalent formation

Human meiosis II. Chromosome pairing and recombination nodules in human spermatocytes

Contact Info

Product

Resources

About