Recombination in male and female meiocytes contrasted

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

Genome ◽  
1989 ◽  
Vol 32 (6) ◽  
pp. 1054-1062 ◽  
Author(s):  
E. Jongedijk ◽  
M. S. Ramanna

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.


Genome ◽  
1997 ◽  
Vol 40 (6) ◽  
pp. 879-886 ◽  
Author(s):  
Francis W. J. Havekes ◽  
J. Hans de Jong ◽  
Christa Heyting

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.


2018 ◽  
Author(s):  
Pasquale Termolino ◽  
Matthieu Falque ◽  
Gaetana Cremona ◽  
Rosa Paparo ◽  
Antoine Ederveen ◽  
...  

AbstractDuring meiosis, recombination ensures the allele exchange through crossovers (COs) between the homologous chromosomes and, additionally, their proper segregation. CO events are under a strict control but molecular mechanisms underlying CO regulation are still elusive. Some advances in this field were made by structural chromosomal rearrangements that are known at heterozygous state to impair COs in various organisms. In this paper, we have investigated the effect that a large pericentric inversion involving chromosome 3 of Arabidopsis thaliana has on male and female recombination. The inversion associated to a T-DNA dependent mutation likely resulted from a side effect of the T-DNA integration. Reciprocal backcross populations, each consisting of over 400 individuals, obtained from the T-DNA mutant and the wild type, both crossed with Landsberg, have been analyzed at genome-wide level by 143 SNPs. We found a strong suppression of COs in the rearranged region in both male and female meiosis. As expected, we did not detect single COs in the inverted region consistently with the post-meiotic selection operating against unbalanced gametes. Cytological analysis of chiasmata in F1 plants confirmed that COs are effectively dropping in chromosome 3 pair. Indeed, CO failure within the inversion is not altogether counterbalanced by CO increase in the regions outside the inversion on chromosome 3. Strikingly, this CO suppression induces a significant increase of COs in chromosome pairs 1, 2 and 5 in male meiosis. We conclude that these chromosomes acquire additional COs thereby compensating the recombination suppression occurring in chromosome 3, similarly to what has been described as interchromosomal (IC) effect in other organisms. In female meiosis, IC effect is not evident. This may be related to the fact that CO number in female is close to the minimum value imposed by the obligatory CO rule.Author SummaryIt is well known that chromosome structure changes in heterozygous condition influence the pattern of meiotic recombination at broad scale. In natural populations, inversions are recognized as the most effective force to reduce COs. In this way, adaptive allele combinations which otherwise would be broken by recombination are maintained. In the present work, we studied the effect on recombination of a large pericentric inversion involving Arabidopsis chromosome 3. The analysis on heterozygous populations provided evidence of strong recombination suppression in chromosome 3. However, the most striking aspect of this study is the finding that the failure of chromosome 3 to recombine is coupled to increased CO frequencies on the other chromosome pairs in male meiosis. These CO compensatory increases are strictly an interchromosomal (IC) effect as was first described in Drosophila. As far as we know, it is the first time IC effect has been reported in plants. Unfortunately, the molecular mechanisms underlying IC effect in the other organisms are still elusive. To understand how a CO change on just one chromosome triggers the global response of the meiocyte to obtain the adequate CO number/cell remains a fascinating question in sexually reproducing species.


1977 ◽  
Vol 24 (1) ◽  
pp. 131-141
Author(s):  
S.E. Hartley ◽  
H.G. Callan

In a wild population of the American newt Notophthalmus viridescens 15 females out of a total of 94 were found to be heterozygous for a paracentric inversion which includes almost the whole of the longer arm of the smallest chromosome (XI). The inversion was recognized in preparations of lampbrush chromosomes because it transfers the sequential loops, which normally lie close to the telomere, to a position neighbouring the centromere. Because of inversion the transcriptional polarity of the sequential loops is reversed vis-a—vis the chromosome as a whole. In normal bivalents XI (both in male and female meiosis) each arm pair generally forms a single chiasma close to the telomeres (proterminal localization). In bivalents XI heterozygous for the inversion no chiasmata are formed between the mutually inverted longer arm pairs, presumably because they fail to synapse, but chiasma frequency in the non-inverted shorter arm pairs is increased, and the normal restraint on chiasma distribution in this arm pair is lifted. An explanation is offered in terms of the availability of recombination nodules, and the time of their association with the synaptonemal complex.


1973 ◽  
Vol 183 (1072) ◽  
pp. 301-319 ◽  

Few recent investigations have been made of female meiosis in cereals, and almost nothing is known about the duration of female meiosis in higher plants. Consequently, the time and duration of female meiosis in Triticum aestivum , Hordeum vulgare and Secale cereale have been studied. The appearance of the embryo sac mother cell (e. m. c.) and of the meiotic nuclei during female meiosis in Hordeum vulgare is described and illustrated. In the species studied, each floret contains only one ovary with a single e. m. c., and meiosis is almost synchronous in the pollen mother cells from all three anthers. Conse­quently, it is possible to make precise comparisons between the stages of male and female development within individual florets. Data from these comparisons, together with know­ledge previously determined of the duration of male meiosis in these species, allowed the estimation of the time and duration of female meiosis fairly accurately for T. aestivum and H. vulgare and approximately for S. cereale . The results showed that for H. vulgar and T. aestivum grown at 20°C, the duration of female meiosis was very similar to the duration of male meiosis. Furthermore, on average male and female meiosis occurred almost synchronously. In S. cereale however, male meiosis preceeded female meiosis by about 15 h. Growing T. aestivum under environmental stress induced asynchrony between male and female development at meiosis. Synchrony was not re-established after a long period under normal conditions. Nuclear DNA content and ploidy level are known to be important factors determining or affecting the duration of male meiosis. These factors appear to play an important role in controlling the duration of female meiosis also.


1998 ◽  
Vol 140 (5) ◽  
pp. 1003-1012 ◽  
Author(s):  
Daniel P. Moore ◽  
Andrea W. Page ◽  
Tracy Tzu-Ling Tang ◽  
Anne W. Kerrebrock ◽  
Terry L. Orr-Weaver

The Drosophila MEI-S332 protein has been shown to be required for the maintenance of sister-chromatid cohesion in male and female meiosis. The protein localizes to the centromeres during male meiosis when the sister chromatids are attached, and it is no longer detectable after they separate. Drosophila melanogaster male meiosis is atypical in several respects, making it important to define MEI-S332 behavior during female meiosis, which better typifies meiosis in eukaryotes. We find that MEI-S332 localizes to the centromeres of prometaphase I chromosomes in oocytes, remaining there until it is delocalized at anaphase II. By using oocytes we were able to obtain sufficient material to investigate the fate of MEI-S332 after the metaphase II–anaphase II transition. The levels of MEI-S332 protein are unchanged after the completion of meiosis, even when translation is blocked, suggesting that the protein dissociates from the centromeres but is not degraded at the onset of anaphase II. Unexpectedly, MEI-S332 is present during embryogenesis, localizes onto the centromeres of mitotic chromosomes, and is delocalized from anaphase chromosomes. Thus, MEI-S332 associates with the centromeres of both meiotic and mitotic chromosomes and dissociates from them at anaphase.


1896 ◽  
Vol 42 (179) ◽  
pp. 787-790 ◽  
Author(s):  
A. R. Turnbull

My object in this paper is to give a brief note of a trial which has recently been made in the Fife Asylum, in the way of introducing female nursing in the male sick-room. Nursing is peculiarly woman's province; and it has, I believe, often been felt that it would be a great advantage if female care could be more freely utilised in the management of male insane patients, or at least of those of them who are suffering from special bodily disease in addition to the mental symptoms. The main objections to the step have hitherto been: (1) that some of the habits and peculiarities of the male insane may make it unfit or undesirable to have them under female care; and (2) that in many asylums the structural arrangement makes it difficult or impossible to bring the male sick-room under systematic supervision by the female staff. Lately it was necessary to build a large addition to the Fife Asylum; and advantage was taken of this opportunity to get rid of the second objection mentioned. The new building is a hospital block, and is intended to receive recent admissions, cases requiring special observation on account of their mental state, and cases of bodily illness. Each side (male and female) is divided into three sections: 1st, sickroom proper (for cases of bodily illness); 2nd, special observation ward (intended for new cases, and cases needing continuous supervision on account of suicidal or other dangerous tendency); and 3rd, general observation ward. There are the usual dining-hall, kitchen, and administrative rooms in the centre of the building. The male and female sick-rooms are placed next to the administrative portion, one on each side; and as the doors here are unlocked during the day, with free communication by the corridor, the male sick-room is easily reached from the female side, and is administered by the matron, the head nurse (who has charge of both sick-rooms), and two junior nurses. Each sick-room communicates with a special observation dormitory, beyond which again is the special observation day-room. This dormitory is empty during the day, but receives at night the cases which require continuous supervision on account of suicidal tendency, and which come to it direct from the special observation day-room. On the male side the door between the sick-room and the observation dormitory is kept locked during the day; and there is thus no direct communication between the sick-room and those parts of the male side which are under the charge of attendants, except by the general corridor. When the Medical Officer makes the evening visit, this door is unlocked, and the sick-room and observation dormitory are thrown into one and come under the charge of a male attendant, who is on duty during the whole night, while the nurses return to the female side of the building. This plan was followed because our numbers are too small to require separate attendance in the two rooms; and in this way the sick-room is under female care during the day, but is supervised at night by the male staff.∗


2003 ◽  
Vol 67 (1) ◽  
pp. 116-126 ◽  
Author(s):  
Christian Olesen ◽  
Morten Møller ◽  
Anne Grete Byskov

2020 ◽  
Vol 12 (11) ◽  
pp. 1961-1964
Author(s):  
Maki Fukami ◽  
Yasuko Fujisawa ◽  
Hiroyuki Ono ◽  
Tomoko Jinno ◽  
Tsutomu Ogata

Abstract Mammalian male meiosis requires homologous recombination between the X and Y chromosomes. In humans, such recombination occurs exclusively in the short arm pseudoautosomal region (PAR1) of 2.699 Mb in size. Although it is known that complete deletion of PAR1 causes spermatogenic arrest, no studies have addressed to what extent male meiosis tolerates PAR1 size reduction. Here, we report two families in which PAR1 partial deletions were transmitted from fathers to their offspring. Cytogenetic analyses revealed that a ∼400-kb segment at the centromeric end of PAR1, which accounts for only 14.8% of normal PAR1 and 0.26% and 0.68% of the X and Y chromosomes, respectively, is sufficient to mediate sex chromosomal recombination during spermatogenesis. These results highlight the extreme recombinogenic activity of human PAR1. Our data, in conjunction with previous findings from animal studies, indicate that the minimal size requirement of mammalian PARs to maintain male fertility is fairly small.


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