Comparative analysis of female and male meiosis in three meiotic mutants of tomato

Genome ◽  
1997 ◽  
Vol 40 (6) ◽  
pp. 879-886 ◽  
Author(s):  
Francis W. J. Havekes ◽  
J. Hans de Jong ◽  
Christa Heyting
Keyword(s):  
Comparative Analysis ◽  
Chromosome Pairing ◽  
Meiotic Prophase ◽  
Chiasma Frequency ◽  
Chiasma Formation ◽  
Male Meiosis ◽  
Wild Type ◽  
Female Meiosis ◽  
Similar Reduction ◽  
Meiotic Mutants

Female meiosis was analysed in squash preparations of ovules from three meiotic mutants and wild-type plants of tomato. In the completely asynaptic mutant as6, chromosome pairing and chiasma formation were virtually absent in both sexes. In the partially asynaptic mutant asb, with intermediate levels of chromosome pairing at pachytene, there were a higher number of chiasmate chromosome arms in female meiosis than in male meiosis, whereas in the desynaptic mutant as5 there were normal levels of chromosome pairing at pachytene and a similar reduction in chiasma frequency in the two sexes. In wild-type tomato, we found slightly higher numbers of chiasmate chromosome arms in female meiosis than in male meiosis. We propose that the higher female chiasma frequencies in mutant asb and wild-type tomato result from a longer duration of female meiotic prophase. This would allow chromosomes more time to pair and recombine. It is possible that a longer duration of prophase I does not affect mutants as5 and as6, either because the meiotic defect acts before the pairing process begins (in as6) or because it acts at a later stage and involves chiasma maintenance (in as5).Key words: female meiosis, tomato, chiasma, mutant.

Synaptic mutants in potato, Solanum tuberosum L. II. Concurrent reduction of chiasma frequencies in male and female meiosis of ds-1 (desynapsis) mutants

Genome ◽  
1989 ◽  
Vol 32 (6) ◽  
pp. 1054-1062 ◽  
Author(s):  
E. Jongedijk ◽  
M. S. Ramanna
Keyword(s):  
Chiasma Frequency ◽  
Solanum Tuberosum L ◽  
Chiasma Formation ◽  
Male Meiosis ◽  
Frequency Variation ◽  
Female Meiosis ◽  
Male And Female ◽  
A Cell ◽  
The Mean ◽  
Mother Cells

Chiasma frequencies in pollen mother cells and megaspore mother cells from both normal and desynaptic (ds-1ds-1) diploid potato clones were estimated on the basis of chiasmate chromosome arm association in metaphase I. In desynaptic mutants both the mean chiasma and bivalent frequencies per cell and the mean chiasma frequency per bivalent proved to be significantly lower. Despite significant differences in within-cell chiasma frequency variation among and particularly between normal and desynaptic clones, no clear effects of the ds-1 gene on the distribution of chiasmata over chromosomes in a cell were detected. The distribution of chiasmata over chromosomes appeared to be more or less random in both normal and desynaptic plants, which suggests that the ds-1 gene similarly affects chiasma frequencies in all chromosomes. Genetic data reported in the literature indicate that the ds-1 gene affects both the overall chiasma frequency and the chiasma distribution along individual chromosomes rather than chiasma maintenance. Sex differences in chiasma formation were not observed among normal plants or among desynaptic mutants, which indicates that chiasma formation in male and female meiosis of potato is governed by a single control system that is similarly expressed in both sexes.Key words: Solanum, desynapsis, chiasma frequency, male meiosis, female meiosis.

A requirement for the Abnormal Spindle protein to organise microtubules of the central spindle for cytokinesis inDrosophila

2002 ◽  
Vol 115 (5) ◽  
pp. 913-922 ◽  
Author(s):  
Maria Giovanna Riparbelli ◽  
Giuliano Callaini ◽  
David M. Glover ◽  
Maria do Carmo Avides
Keyword(s):  
Spindle Pole Body ◽  
Spindle Pole ◽  
Male Meiosis ◽  
Wild Type ◽  
Female Meiosis ◽  
Central Spindle ◽  
Spindle Poles ◽  
Late Anaphase ◽  
Mutant Cells ◽  
Sperm Aster

Drosophila abnormal spindle (asp) mutants exhibit a mitotic metaphase checkpoint arrest with abnormal spindle poles, which reflects a requirement for Asp for the integrity of microtubule organising centres (MTOCs). In male meiosis, the absence of a strong spindle integrity checkpoint enables asp mutant cells to proceed through anaphase and telophase. However, the central spindle region is not correctly organised and cells frequently fail to complete cytokinesis. This contrasts with meiosis in wild-type males where at late anaphase a dense array of microtubules forms in the central spindle region that has Asp localised at its border. We speculate that Asp is associated with the minus ends of microtubules that have been released from the spindle poles to form the central spindle. A parallel situation arises in female meiosis where Asp not only associates with the minus ends of microtubules at the acentriolar poles but also with the central spindle pole body that forms between the two tandem spindles of meiosis II. Upon fertilisation, Asp is also recruited to the MTOC that nucleates the sperm aster. Asp is required for growth of the microtubules of the sperm aster,which in asp mutants remains diminutive and so prevents migration of the pronuclei.

Recombination in male and female meiocytes contrasted

1977 ◽  
Vol 277 (955) ◽  
pp. 227-233 ◽  
Keyword(s):  
Chiasma Frequency ◽  
Male Meiosis ◽  
Comparative Data ◽  
Evolutionary Significance ◽  
Female Meiosis ◽  
Male And Female ◽  
Intrachromosomal Recombination ◽  
Male Side ◽  
Chromosomal Recombination

For technical reasons studies of chiasma frequency and distribution, and hence of intrachromosomal recombination, have mostly been confined to male meiosis. However, there is now sufficient comparative data on male and female meiosis, in both plants and animals, to show that the extent of intra-chromosomal recombination in some organisms may be much the same on the female as on the male side, whereas other organisms show extreme sexual divergence in this regard. The evolutionary significance of such diversity remains enigmatic

scholarly journals Evidence of premeiotic control of chromosome pairing in Triticum aestivum

1972 ◽  
Vol 20 (2) ◽  
pp. 201-212 ◽  
Author(s):  
M. W. Bayliss ◽  
Ralph Riley
Keyword(s):  
Chromosome Pairing ◽  
Chiasma Frequency ◽  
Sequential Sampling ◽  
Chiasma Formation ◽  
Temperature Sensitive ◽  
Final Temperature ◽  
Similar Time ◽  
Temperature Changes ◽  
Critical Range ◽  
Sensitive Stage

SUMMARYA genotype of wheat deficient for a pair of chromosomes stabilizing chiasma frequency against extremes of temperature was investigated to determine the position and duration of temperature sensitivity with respect to first metaphase of meiosis. Temperature changes over a critical range, followed by sequential sampling and measurement of chiasma frequency, showed a relatively short temperature-sensitive stage, the position and duration of which were dependent on the final temperature used. Comparison with meiotic timings made independently showed that the temperature-sensitive stage occurred in the premeiotic interphase. Euploid wheat was shown to have a stage in chiasma formation sensitive to high-temperature treatments at a similar time.Comparison with the work of others showed that the sensitive stage lay between the last premeiotic mitosis and the start of DNA synthesis. This modification of chromosome pairing at a much earlier stage than has been previously demonstrated is further evidence that the processes of chromosome pairing and crossing-over are probably more complex than formerly envisaged.

scholarly journals Silencing of Unpaired Chromatin and Histone H2A Ubiquitination in Mammalian Meiosis

2005 ◽  
Vol 25 (3) ◽  
pp. 1041-1053 ◽  
Author(s):  
Willy M. Baarends ◽  
Evelyne Wassenaar ◽  
Roald van der Laan ◽  
Jos Hoogerbrugge ◽  
Esther Sleddens-Linkels ◽  
...  
Keyword(s):  
Mouse Models ◽  
Meiotic Prophase ◽  
Transcriptional Silencing ◽  
Male Meiosis ◽  
Histone H2a ◽  
Barr Body ◽  
Female Meiosis ◽  
Autosomal Region ◽  
Y Chromosomes ◽  
The Relationship

ABSTRACT During meiotic prophase in male mammals, the X and Y chromosomes are incorporated in the XY body. This heterochromatic body is transcriptionally silenced and marked by increased ubiquitination of histone H2A. This led us to investigate the relationship between histone H2A ubiquitination and chromatin silencing in more detail. First, we found that ubiquitinated H2A also marks the silenced X chromosome of the Barr body in female somatic cells. Next, we studied a possible relationship between H2A ubiquitination, chromatin silencing, and unpaired chromatin in meiotic prophase. The mouse models used carry an unpaired autosomal region in male meiosis or unpaired X and Y chromosomes in female meiosis. We show that ubiquitinated histone H2A is associated with transcriptional silencing of large chromatin regions. This silencing in mammalian meiotic prophase cells concerns unpaired chromatin regions and resembles a phenomenon described for the fungus Neurospora crassa and named meiotic silencing by unpaired DNA.

Chromosome pairing and chiasma formation in autopolyploids of different Lathyrus species

Genome ◽  
1997 ◽  
Vol 40 (6) ◽  
pp. 937-944 ◽  
Author(s):  
H. I. T. Khawaja ◽  
J. Sybenga ◽  
J. R. Ellis
Keyword(s):  
Gene Flow ◽  
Chromosome Pairing ◽  
Chiasma Frequency ◽  
Chiasma Formation ◽  
Meiotic Metaphase ◽  
Lathyrus Sativus ◽  
Ploidy Levels ◽  
Lathyrus Odoratus ◽  
Mixed Populations ◽  
Tetraploid Level

Chromosome pairing and chiasma formation were studied in natural and induced tetraploids (2n = 28) of Lathyrus odoratus (induced), Lathyrus pratensis (natural and induced), Lathyrus sativus (induced), and Lathyrus venosus (natural), as well as in triploids of L. pratensis and diploids of L. odoratus, L. pratensis, and L. sativus. All natural tetraploids appeared to be autotetraploids and their meiotic metaphase I behaviour was very similar to that of the induced autotetraploids, with average numbers of pairing partner switches exceeding 4 or even 5. Multivalent frequencies were high, but the numbers of chiasmata were not much higher than necessary to maintain the configurations. Interstitial chiasmata were common, but not predominant. Fertility was reduced, but sufficient for predominantly vegetatively reproducing species. The triploids of L. pratensis had an even higher multivalent frequency than the tetraploids, but still produced some viable progeny at or close to the tetraploid level, suggesting that in mixed populations of diploids and tetraploids, triploids can contribute to gene flow between the ploidy levels. There was no significant correlation between chiasma frequency and ring bivalent frequency in the diploids and multivalent frequency in the corresponding tetraploids. In the tetraploids, chiasma frequency and multivalent frequency were negatively correlated.Key words: Lathyrus, natural, induced, autotetraploid, triploid, meiosis.

scholarly journals Unleashing meiotic crossovers in hybrid plants

2017 ◽  
Vol 115 (10) ◽  
pp. 2431-2436 ◽  
Author(s):  
Joiselle Blanche Fernandes ◽  
Mathilde Séguéla-Arnaud ◽  
Cécile Larchevêque ◽  
Andrew H. Lloyd ◽  
Raphael Mercier
Keyword(s):  
Fold Increase ◽  
Pure Line ◽  
Male Meiosis ◽  
Wild Type ◽  
Female Meiosis ◽  
Male Recombination ◽  
Upper Limit ◽  
Hybrid Plants ◽  
Wild Type Female ◽  
Breeding Efficiency

Meiotic crossovers shuffle parental genetic information, providing novel combinations of alleles on which natural or artificial selection can act. However, crossover events are relatively rare, typically one to three exchange points per chromosome pair. Recent work has identified three pathways limiting meiotic crossovers in Arabidopsis thaliana that rely on the activity of FANCM [Crismani W, et al. (2012) Science 336:1588–1590], RECQ4 [Séguéla-Arnaud M, et al. (2015) Proc Natl Acad Sci USA 112:4713–4718], and FIGL1 [Girard C, et al. (2015) PLoS Genet 11:e1005369]. Here we analyzed recombination in plants in which one, two, or all three of these pathways were disrupted in both pure line and hybrid contexts. The greatest effect was observed when combining recq4 and figl1 mutations, which increased the hybrid genetic map length from 389 to 3,037 cM. This corresponds to an unprecedented 7.8-fold increase in crossover frequency. Disrupting the three pathways did not further increase recombination, suggesting that some upper limit had been reached. The increase in crossovers is not uniform along chromosomes and rises from centromere to telomere. Finally, although in wild type recombination is much higher in male meiosis than in female meiosis (490 cM vs. 290 cM), female recombination is higher than male recombination in recq4 figl1 (3,200 cM vs. 2,720 cM), suggesting that the factors that make wild-type female meiosis less recombinogenic than male wild-type meiosis do not apply in the mutant context. The massive increase in recombination observed in recq4 figl1 hybrids opens the possibility of manipulating recombination to enhance plant breeding efficiency.

scholarly journals Heterochronic Expression of Sexual Reproductive Programs During Apomictic Development in Tripsacum

Genetics ◽  
2003 ◽  
Vol 165 (3) ◽  
pp. 1521-1531
Author(s):  
Daniel Grimanelli ◽  
Marcelina García ◽  
Etienne Kaszas ◽  
Enrico Perotti ◽  
Olivier Leblanc
Keyword(s):  
Developmental Stages ◽  
Early Embryo ◽  
Male Meiosis ◽  
Egg Cell ◽  
Wild Type ◽  
Tripsacum Dactyloides ◽  
Female Meiosis ◽  
Parthenogenetic Development ◽  
Reproductive Events ◽  
Natural Way

Abstract Some angiosperms reproduce by apomixis, a natural way of cloning through seeds. Apomictic plants bypass both meiosis and egg cell fertilization, producing progeny that are genetic replicas of the mother plant. In this report, we analyze reproductive development in Tripsacum dactyloides, an apomictic relative of maize, and in experimental apomictic hybrids between maize and Tripsacum. We show that apomictic reproduction is characterized by an alteration of developmental timing of both sporogenesis and early embryo development. The absence of female meiosis in apomictic Tripsacum results from an early termination of female meiosis. Similarily, parthenogenetic development of a maternal embryo in apomicts results from precocious induction of early embryogenesis events. We also show that male meiosis in apomicts is characterized by comparable asynchronous expression of developmental stages. Apomixis thus results in an array of possible phenotypes, including wild-type sexual development. Overall, our observations suggest that apomixis in Tripsacum is a heterochronic phenotype; i.e., it relies on a deregulation of the timing of reproductive events, rather than on the alteration of a specific component of the reproductive pathway.

A CYTOGENETICAL ANALYSIS OF STERILE MUTANTS IN CAENORHABDITIS ELEGANS

1980 ◽  
Vol 22 (3) ◽  
pp. 391-403 ◽  
Author(s):  
Nicole Mounier ◽  
Jean Brun
Keyword(s):  
Caenorhabditis Elegans ◽  
Oocyte Maturation ◽  
Chromosome Pairing ◽  
Male Meiosis ◽  
Cytological Analysis ◽  
Wild Type ◽  
Nematode Caenorhabditis Elegans ◽  
The Third ◽  
Homozygous Mutant ◽  
Cytogenetical Analysis

The regulation of gametogenesis in the hermaphrodite and proterandrous nematode Caenorhabditis elegans is introduced here through the analysis of nonconditional sterile mutants. To investigate the mechanisms which allow the two gametogenetic phases to succeed each other in the same ovotestis, three mutants were studied cytogenetically. Two of the mutants exhibit only the spermatocyte phase and the third shows a greatly reduced and disturbed oogenesis. These three mutations all produce large decreases in ovotestis size and gonocyte number. Each of the three is monofactorial, recessive, autosomal and independent. Homozygous mutant males are also sterile. The gametogenesis phases which could be disturbed by mutation were determined by cytological analysis of the ovotestis of 12 other sterile strains. These phases occur during mitotic divisions of the genital primordium, zygotene chromosome pairing, male meiosis and spermiogenesis, oogenesis induction and oocyte maturation. These steps of gametogenesis need a wild-type genie activity to occur normally. It appears that spermatogenesis and oogenesis are two genetically independent processes, and that oogenesis is rather autonomous and its induction would depend on a hormonal factor.

scholarly journals Meiotic Aberrations Leading To Aneuploidy In Cauliflower (Brassica Oleracea L. var. Botrytis)

2021 ◽  
Author(s):  
Xianwen Ji ◽  
Cilia Lelivelt ◽  
Erik Wijnker ◽  
Hans de Jong
Keyword(s):  
Brassica Oleracea ◽  
Chromosome Pairing ◽  
Tandem Repeats ◽  
Chiasma Formation ◽  
Male Meiosis ◽  
Genetic And Environmental Factors ◽  
Mother Cells ◽  
Selection Of ◽  
Meiotic Aberrations ◽  
Metaphase I

Abstract Aneuploid cauliflower plants (Brassica oleracea L. var. botrytis) display abnormal curd phenotypes causing serious commercial problems in offspring populations. Despite extensive breeding efforts, selection of genotypes producing euploid gametes remains unsuccessful due to unknown genetic and environmental factors. To reveal the origin of aneuploid gametes, we analyzed chromosome pairing, chiasma formation and chromosome segregation in pollen mother cells of selected cauliflower genotypes. To this end we compared different genotypes exhibiting Low with < 5%, Moderate with 5-10% and High with > 10% aberrant offspring. Microscopic observations revealed regular chromosome pairing at pachytene. However, cells at diakinesis and metaphase I showed variable numbers of univalents, suggesting that chiasma formation during meiotic prophase is incomplete or disrupted and results in a partial desynaptic phenotype. Cells at anaphase I – telophase II exhibited various degrees of unbalanced chromosome numbers explaining the aneuploid offspring. Immunofluorescence probed with an MLH1 antibody demonstrated fluorescent foci in all genotypes, but their lower numbers do not correspond to the putative sites of chiasmata. Interchromosomal connections between chromosomes and bivalents are common at diakinesis and metaphase I, and they contain centromeric and 45S rDNA tandem repeats, but such threads seemed not to affect proper disjoin of the half bivalents at anaphase I. Moreover, male meiosis in the arabidopsis APETALA1/ CAULIFLOWER double mutant with the typical cauliflower phenotype did show interchromosomal connections, but there were no indications for partial desynapsis. We now hypothesize that the occurrence of desynapsis in cauliflower is a developmental out-of-phase phenomenon partially or completely controlled by genes involved in flower and curd development.

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