Meiotic Behavior Research Articles

Introductory data on meiotic structures in Allium senescens L. subsp. montanum (Pohl) Holub

Examples of zygotene chromosomal configurations in Allium senescens subsp. montanum are presented. Bivalents do not dominate in a zygotene stadium. Some bivalent segments show deletions. Also, tri- and tetravalents segments are observed. The conjugation of SAT-chromosome shows that a translocation has occurred in the SAT segment. In addition, univalents indicate that meiotic behaviour of the species is unstable.

A synopsis of the cytogenetics of the genusPhlomoides(Lamiaceae) in Iran

AbstractThe present study reports the chromosome number and meiotic behavior of 11 populations belonging to four species of Phlomoides (L.) Moench. All populations showed the diploid chromosome number 2n = 2x = 22; consistent with the proposed base number of x = 11. Almost all taxa studied here displayed regular bivalent pairing and chromosome segregation at meiosis. However, meiotic abnormalities observed included varied degree of fragmented chromosomes, laggards and bridge in anaphase I to telophase II, precocious division of centromeres, asynchronous nucleus and cytomixis. In addition, a survey on chromosome counts of different species belonging to the genus Phlomoides throughout the world is presented and the base chromosome numbers and polyploidy levels discussed here.

Integrating haplotype-specific linkage maps in tetraploid species using SNP markers.

Key message Linkage mapping can help unravel the complexities of polyploid genomes. Here, we integrate haplotype-specific linkage maps in autotetraploid potato and explore the possibilities for mapping in other polyploid species. High-density linkage mapping in autopolyploid species has become possible in recent years given the increasing number of molecular markers now available through modern genotyping platforms. Such maps along with larger experimental populations are needed before we can obtain sufficient accuracy to make marker-trait association studies useful in practice. Here, we describe a method to create genetic linkage maps for an autotetraploid species with large numbers of markers and apply it to an F1 population of tetraploid potato (Solanum tuberosum L.) of 235 individuals genotyped using a 20K SNP array. SNP intensity values were converted to allele dosages after which we calculated pairwise maximum likelihood estimates of recombination frequencies between all marker segregation types under the assumption of random bivalent pairing. These estimates were used in the clustering of markers into linkage groups and their subsequent ordering into 96 homologue maps. The homologue maps were integrated per chromosome, resulting in a total map length of 1061 cM from 6910 markers covering all 12 potato chromosomes. We examined the questions of marker phasing and binning and propose optimal strategies for both. We also investigated the effect of quadrivalent formation and preferential pairing on recombination frequency estimation and marker phasing, which is of great relevance not only for potato but also for genetic studies in other tetraploid species for which the meiotic pairing behaviour is less well understood.Electronic supplementary materialThe online version of this article (doi:10.1007/s00122-016-2768-1) contains supplementary material, which is available to authorized users.

Interspecific hybrids between Paspalum plicatulum and P. oteroi: a key tool for forage breeding

Grama-tio-pedro (Paspalum oteroi Swallen) is a rare stoloniferous grass of the Plicatula group of Paspalum, well adapted to continuous grazing in areas subject to seasonal flooding in the Pantanal region, in central western Brazil. The species is a facultative apomictic (asexual reproduction by seed) tetraploid, sporadically cultivated on Pantanal farms, propagated either by cuttings or seed. Due to its potential for extensive cultivation and forage quality, Grama-tio-pedro appears as a candidate for genetic improvement within the Plicatula group through plant breeding. We used a colchicine-induced sexual autotetraploid genotype of P. plicatulum Michx. to obtain interspecific hybrids using the apomictic species, P. oteroi, as pollen donor. The very similar meiotic chromosome behavior observed in both parents, with main quadrivalent and bivalent associations, suggested that P. oteroi is a natural autotetraploid. The hybrids showed less irregular meiotic behavior with fewer quadrivalents and more bivalents than either parent. Fertility among interspecific hybrids varied from complete sterility in some of them to seed productions in others that were approximately twice as much as for either parent. The great variability of seed set performance may well be a drastic genetic consequence of joining two homologous chromosome sets of P. plicatulum together with two homologous sets of P. oteroi that, in turn, have some homeology between them. Most hybrids reproduce by sexual means, thus, they could be used as female parents in backcrosses and in crosses with other species of the Plicatula group for interspecific gene transferring in breeding programs.

MICROSPOROGÉNESIS DE TRES ESPECIES DEL SUBGÉNERO PASSIFLORA (PASSIFLORA, PASSIFLORACEAE) DE PARAGUAY

The aim of the present study was to characterize karyologically species of Passiflora L. from Felix Perez Cardozo District, Guaira, Paraguay. The chromosome numbers in meiosis 2n = 9II for P. alata Curtis and P. caerulea L. are reported for the first time. Chromosome number for P. edulis Sims (2n = 9II) is also confirmed. Meiotic behaviour in all studied species was normal with regular chromosome segregation. The most frequent chromosome associations were bivalents at diakinesis and metaphase I. Few meiotic irregularities were observed, such as lagging chromosomes and asynchronous phases of meiosis II, however, pollen viability was high, between 78.83% and 98.6%. The obtained results confirms x = 9 as the basic chromosome number for subgenus Passiflora. The present study is a relevant contribution to the knowledge on the cytogenetics of species of Passiflora subg Passiflora from Paraguay.

Mouse D1Pas1, a DEAD-box RNA helicase, is required for the completion of first meiotic prophase in male germ cells

D1Pas1 is a mouse autosomal DEAD-box RNA helicase expressed predominantly in the testis. To assess its possible function, we generated D1Pas1-deficient mice using embryonic stem cells with a targeted D1Pas1 allele. Deletion of D1Pas1 did not cause noticeable embryonic defects or death, indicating that D1Pas1 is not essential for embryogenesis. Whereas homozygous knockout female mice showed normal reproductive performance, homozygous knockout male mice were completely sterile. The seminiferous epithelium of D1Pas1-deficient males contained no spermatids or spermatozoa because of spermatogenic arrest at the late pachytene stage. Upregulation of retrotransposons such as LINE-1 was not found in D1Pas1-deficient males, unlike males lacking Mvh, another testicular DEAD-box RNA helicase. Meiotic chromosome behavior in developing spermatocytes of D1Pas1-deficient males was indistinguishable from that in wild-type males, at least until synaptonemal complex formation. Thus, mouse D1Pas1 is the first-identified DEAD-box RNA helicase that plays critical roles in the final step of the first meiotic prophase in male germ cells.

Unique sex chromosome systems in Ellobius: How do male XX chromosomes recombine and undergo pachytene chromatin inactivation?

Most mammalian species have heteromorphic sex chromosomes in males, except for a few enigmatic groups such as the mole voles Ellobius, which do not have the Y chromosome and Sry gene. The Ellobius (XX ♀♂) system of sex chromosomes has no analogues among other animals. The structure and meiotic behaviour of the two X chromosomes were investigated for males of the sibling species Ellobius talpinus and Ellobius tancrei. Their sex chromosomes, despite their identical G-structure, demonstrate short synaptic fragments and crossover-associated MLH1 foci in both telomeric regions only. The chromatin undergoes modifications in the meiotic sex chromosomes. SUMO-1 marks a small nucleolus-like body of the meiotic XX. ATR and ubiH2A are localized in the asynaptic area and the histone γH2AFX covers the entire XX bivalent. The distribution of some markers of chromatin inactivation differentiates sex chromosomes of mole voles from those of other mammals. Sex chromosomes of both studied species have identical recombination and meiotic inactivation patterns. In Ellobius, similar chromosome morphology masks the functional heteromorphism of the male sex chromosomes, which can be seen at meiosis.

High-frequency somatic embryogenesis and artificial seeds for mass production of true-to-type plants in Ledebouria revoluta: an important cardioprotective plant

Scaly bulb of Ledebouria revoluta is a natural source of several cardiac glycosides and is traditionally used in Indian and South African ethno-medicinal system from ancient age. High-frequency indirect somatic embryogenesis protocol via callus culture had been developed from bulb scale explant. Optimum embryogenic calli was induced on Murashige and Skoog (MS) medium supplemented with 3.0 mg l−1 2,4-dichlorophenoxyacetic acid and 0.75 mg l−1 β-naphthoxyacetic acid. A maximum of 93.3 % of the cultures responded after 6 weeks of culture on MS medium containing 3.0 mg l−1 of thidiazuron, 0.75 mg l−1 α-naphthalene acetic acid and 1.75 mM spermidine forming 46.7 ± 0.58 somatic embryos per 500 mg callus. Individual somatic embryo was encapsulated in calcium alginate beads to produce artificial seeds (ASs). The ASs were stored at 4, 15, and 24 °C temperatures up to 180 days. The ASs showed 57.8 % germinability even after 4 months of storage at 15 °C. Plantlets were acclimatized with a survival rate of 96.0 % and after 13–14 months, 92.4 % of these plants produced flowers. Chromosomal studies revealed cytological stability of the regenerants containing 2n = 30 chromosomes in root tips and n = 15 chromosomes in pollen grains, same as parental plants. The meiotic behaviour of the regenerants is also similar to that of parental plants. Randomly amplified polymorphic DNA analysis revealed that there is no somaclonal variations among the plants produced via somatic embryogenesis and they are true-to-type to their parental plant. These results confirm the very reliable method for short-term conservation and large-scale production of true-to-type plantlets of L. revoluta, which can be applied in pharmaceutical industries.

Asynchronous meiosis in Cucumis hystrix–cucumber synthetic tetraploids resulting in low male fertility

Interspecific hybridization and allopolyploidization contribute to the improvement of many important crops. Recently, we successfully developed an amphidiploid from an interspecific cross between cucumber (Cucumis sativus, 2n=2x=14) and its relative C. hystrix (2n=2x=24) followed by chemical induction of chromosome doubling. The resulting allotetraploid plant was self-pollinated for three generations. The fertility and seed set of the amphidiploid plants were very low. In this study, we investigated the meiotic chromosome behavior in pollen mother cells with the aid of fluorescence in situ hybridization, aiming to identify the reasons for the low fertility and seed set in the amphidiploid plants. Homologous chromosome pairing appeared normal, but chromosome laggards were common, owing primarily to asynchronous meiosis of chromosomes from the two donor genomes. We suggest that asynchronous meiotic rhythm between the two parental genomes is the main reason for the low fertility and low seed set of the C. hystrix–cucumber amphidiploid plants.

Possible origin of B chromosome in Dichotomius sericeus (Coleoptera)

B chromosomes have so far been described in about 80 species of Coleoptera, mainly using conventional staining analysis. In this study, 152 individuals of the dung beetle Dichotomius sericeus (Coleoptera), collected from three isolated geographical areas in the State of Pernambuco, Brazil, were analyzed to determine the frequency, prevalence, distribution, meiotic behavior, and possible B chromosome origin. The cytogenetic analysis consisted of conventional staining, C-banding, triple fluorochrome staining (CMA3/DA/DAPI), and fluorescent in situ hybridization using ribosomal DNAs (rDNAs) and H3 histone gene as probes, as well as microdissection and chromosome painting of the B chromosome. The B chromosomes were detected in all populations analyzed. Analysis revealed the heterochromatic nature and the presence of G+C-rich blocks and 18S rDNA on the B chromosome. FISH with DNA from microdissected B chromosome painted the entire extension of the B chromosome for all populations, besides the pericentromeric regions of all the autosomes, as well as the X chromosome. Finally, cross-hybridization in nine related species of Dichotomius using the microdissected B chromosome as probe did not reveal any hybridization signal. The results suggest an intraspecific and monophyletic origin for B chromosomes in D. sericeus, probably from the second or third autosomal pair.

Meiotic behavior and H3K4m distribution in B chromosomes of Characidium gomesi (Characiformes, Crenuchidae).

Characidium gomesi Travasso, 1956 specimens from the Pardo River have up to four heterochromatic supernumerary chromosomes, derived from the sex chromosomes. To access the meiotic behavior and distribution of an active chromatin marker, males and females of Characidium gomesi with two or three B chromosomes were analyzed. Mitotic chromosomes were characterized using C-banding and FISH with B chromosome probes. Meiocytes were subjected to immunofluorescence-FISH assay using anti-SYCP3, anti-H3K4m, and B chromosomes probes. Molecular homology of supernumeraries was confirmed by FISH and by its bivalent conformation in individuals with two of these chromosomes. In individuals with three Bs, these elements formed a bivalent and a univalent. Supernumerary and sex chromosomes exhibited H3K4m signals during pachytene contrasting with their heterochromatic and asynaptic nature, which suggest a more structural role than functional of this histone modification. The implications of this result are discussed in light of the homology, meiotic nuclear organization, and meiotic silencing of unsynapsed chomatin.

Meiotic behaviour of evolutionary sex-autosome translocations in Bovidae.

The recurrent occurrence of sex-autosome translocations during mammalian evolution suggests common mechanisms enabling a precise control of meiotic synapsis, recombination and inactivation of sex chromosomes. We used immunofluorescence and FISH to study the meiotic behaviour of sex chromosomes in six species of Bovidae with evolutionary sex-autosome translocations (Tragelaphus strepsiceros, Taurotragus oryx, Tragelaphus imberbis, Tragelaphus spekii, Gazella leptoceros and Nanger dama ruficollis). The autosomal regions of fused sex chromosomes showed normal synapsis with their homologous counterparts. Synapsis in the pseudoautosomal region (PAR) leads to the formation of characteristic bivalent (in T. imberbis and T. spekii with X;BTA13/Y;BTA13), trivalent (in T. strepsiceros and T. oryx with X/Y;BTA13 and G. leptoceros with X;BTA5/Y) and quadrivalent (in N. dama ruficollis with X;BTA5/Y;BTA16) structures at pachynema. However, when compared with other mammals, the number of pachynema lacking MLH1 foci in the PAR was relatively high, especially in T. imberbis and T. spekii, species with both sex chromosomes involved in sex autosome translocations. Meiotic transcriptional inactivation of the sex-autosome translocations assessed by γH2AX staining was restricted to their gonosomal regions. Despite intraspecies differences, the evolutionary fixation of sex-autosome translocations among bovids appears to involve general mechanisms ensuring sex chromosome pairing, synapsis, recombination and inactivation.

Variation in Copy Number of Ty3/Gypsy Centromeric Retrotransposons in the Genomes of Thinopyrum intermedium and Its Diploid Progenitors.

Speciation and allopolyploidization in cereals may be accompanied by dramatic changes in abundance of centromeric repeated transposable elements. Here we demonstrate that the reverse transcriptase part of Ty3/gypsy centromeric retrotransposon (RT-CR) is highly conservative in the segmental hexaploid Thinopyrum intermedium (JrJvsSt) and its possible diploid progenitors Th. bessarabicum (Jb), Pseudoroegneria spicata (St) and Dasypyrum villosum (V) but the abundance of the repeats varied to a large extent. Fluorescence in situ hybridization (FISH) showed hybridization signals in centromeric region of all chromosomes in the studied species, although the intensity of the signals drastically differed. In Th. intermedium, the strongest signal of RT-CR probe was detected on the chromosomes of Jv, intermediate on Jr and faint on Js and St subgenome suggesting different abundance of RT-CR on the individual chromosomes rather than the sequence specificity of RT-CRs of the subgenomes. RT-CR quantification using real-time PCR revealed that its content per genome in Th. bessarabicum is ~ 2 times and P. spicata is ~ 1,5 times higher than in genome of D. villosum. The possible burst of Ty3/gypsy centromeric retrotransposon in Th. intermedium during allopolyploidization and its role in proper mitotic and meiotic chromosome behavior in a nascent allopolyploid is discussed.

Cytogenetic Behavior of Trigeneric Hybrid Progeny Involving Wheat, Rye and Psathyrostachys huashanica

Trigeneric hybrids are commonly used as bridges to transfer genes from some wild species to cultivated wheat and to measure the genomic interaction between donor species. We previously reported that trigeneric germplasms were produced by crossing wheat-Psathyrostachys huashanica amphiploids (PHW-SA, 2n = 8x = 56, AABBDDNsNs) with hexaploid triticale (Zhongsi 828, 2n = 6x = 42, AABBRR). In the present study, chromosome pairing behavior and the genome constitution of the F₄ progenies of wheat-rye-P. huashanica trigeneric hybrids were studied. Cytological analysis showed that the chromosome number of F₄ progenies ranged from 39 to 46, and 57.5% of them had 42 chromosomes. The mean meiotic configuration of F₄ lines was 1.71 univalents, 20.26 bivalents, 0.04 trivalents, and 0.001 quadrivalents per pollen mother cell. Among the lines with 2n = 42, the average pairing configuration was 1.21 univalents, 16.22 ring bivalents, 4.16 rod bivalents, and 0.01 trivalents. This result indicated that these lines were cytologically stable. Other lines with 2n = 39, 40, 41, 43, 44, 45, and 46, bearing a high number of univalents or multivalents, showed abnormal meiotic behavior. Genomic in situ hybridization (GISH) revealed that all F₄ lines had 11-14 rye chromosomes, but no P. huashanica chromosomes. The complete set of 14 rye chromosomes was found in 19 lines. At meiosis, GISH detected 1-6 univalents with hybridization signals of rye in 13 lines. Bivalents with fluorescence signals were identified in each line, ranging from 3 to 7. A quadrivalent with hybridization signals was observed in only 1 line, K13-714-8. Lagging chromosomes, chromosome bridges, micronuclei, and chromosome fragments hybridizing with the probe were not discovered in any of the lines. These results inferred that the behavior of rye chromosomes was normal during meiosis. In addition, 21 lines of 2n = 42 (91.3%) with 12 or 14 rye chromosomes, always contained 6 or 7 bivalents bearing fluorescence signals. This suggested that the rye chromosomes exhibiting complete pairing in these lines were cytologically stable during meiosis and may therefore be considered as new hexaploid triticales. Thus, these lines might be potential materials for further hexaploid triticale improvement.

Modeling meiotic chromosome pairing: nuclear envelope attachment, telomere-led active random motion, and anomalous diffusion

The recognition and pairing of homologous chromosomes during meiosis is a complex physical and molecular process involving a combination of polymer dynamics and molecular recognition events. Two highly conserved features of meiotic chromosome behavior are the attachment of telomeres to the nuclear envelope and the active random motion of telomeres driven by their interaction with cytoskeletal motor proteins. Both of these features have been proposed to facilitate the process of homolog pairing, but exactly what role these features play in meiosis remains poorly understood. Here we investigate the roles of active motion and nuclear envelope tethering using a Brownian dynamics simulation in which meiotic chromosomes are represented by a Rouse polymer model subjected to tethering and active forces at the telomeres. We find that tethering telomeres to the nuclear envelope slows down pairing relative to the rates achieved by unattached chromosomes, but that randomly directed active forces applied to the telomeres speed up pairing dramatically in a manner that depends on the statistical properties of the telomere force fluctuations. The increased rate of initial pairing cannot be explained by stretching out of the chromosome conformation but instead seems to correlate with anomalous diffusion of sub-telomeric regions.

Distinct subgenome stabilities in synthesized Brassica allohexaploids.

Trigenomic Brassica allohexaploids synthesized from three crossing strategies showed diploidized and non-diploidized meiotic behaviors and produced both euploid and aneuploid progenies during successive generations, revealing the distinct subgenome stabilities (B>A>C). Three cultivated allotetraploid Brassica species (Brassica napus, B. juncea, B. carinata) represent the model system of speciation through interspecific hybridization and allopolyploidization, but no Brassica species at higher ploidy level exists in nature. In this study, Brassica allohexaploids (2n=54, AABBCC) were artificially synthesized using three crossing strategies, and had combinations of the genomes from the extant allotetraploids and diploids (B. rapa, B. oleracea and B. nigra). The chromosome numbers and complements of these allohexaploids and the self-pollinated progenies of successive generations (S0-S7) were determined using multicolor fluorescent in situ hybridization that distinguished the chromosomes of three constituent genomes from each other. Both euploid and aneuploid progenies were identified. The most aneuploids maintained all B- and A-genome chromosomes and variable number of C-genome chromosomes, suggesting that genome stability was B>A>C. In the extreme case, loss of whole set of C-genome chromosomes led to the production of B. juncea-type progeny. Some aneuploid progenies had the same number of chromosomes (2n=54) as the euploid, but the simultaneous loss and gain of A- and C-genome chromosomes. The diploidized and non-diploidized meiotic behaviors co-occurred in all allohexaploid individuals of consecutive generations. The aberrant chromosome pairing and segregation mainly involved the chromosomes of A and C genomes, which resulted in aneuploidy in self-pollinated progenies. The mechanisms for the differential stability of three genomes and the stabilization of the new allohexaploids are discussed.

Evaluating interspecific wheat hybrids based on heat and drought stress tolerance

Three durum and three bread wheat genotypes were crossed to produce three tetraploid, three hexaploid and nine interspecific (pentaploid) F1 hybrids. All genotypes were evaluated for heat tolerance in the field and for drought using polyethylene glycol in vitro. Chromosome numbers and meiotic behavior in pentaploid F1 hybrids (2n=5x=35, genomes AABBD) were confirmed. Heat stress significantly reduced grain yield/plant and 1000-kernel weight (1000-KW), while grain protein content (GPC) was increased. Drought caused a significant reduction in root length, shoot length and seedling fresh weight, whereas root/shoot ratio was increased. P3 (durum), P4 (bread) and their pentaploid F1 hybrid could be considered as the most heat-tolerant genotypes. However, P2 (durum), P6 (bread) and their F1 were most tolerant to drought. The addition of a D genome single dose into pentaploid F1 hybrids obviously reduced grain yield/plant, 1000-KW and seedling traits, however GPC was increased. Moderate to high broad-sense heritability and genetic advance were obtained for the most investigated traits. Grain yield/plant was strongly positively correlated with stress tolerance index (STI), yield index (YI), mean productivity (MP), geometric mean productivity (GMP) and harmonic mean (HM) under heat stress and with root length under drought condition, suggesting that STI, YI, MP, GMP and HM are powerful indices for heat tolerance, while root length is most effective for drought. Successful interspecific hybridization obtained in the study is only an initial step for desired genes introgression. Successive progenies are going to be evaluated for further genetic studies aiming at improving abiotic stress tolerance in wheat.

Features of chromosome behavior in meiosis in common wheat lines containing genetic material of tetraploid wheat species

The study of meiotic chromosome behavior in hybrid lines obtained by crossing common wheat with tetraploid wheat species shows that the introgression of alien genetic material into the common wheat genome does not have a negative effect on its meiotic stability. Aberrant cells are few not only in the metaphase but also at the final stage of the tetrads. The variation in the level of cytological stability between the studied lines stems from differences in the number and localization of tetraploid wheat genome fragments in the hybrid genome. The influence of the cytoplasm on the formation of the karyotype of wheat introgression lines has been detected.

Research on meiotic chromosome pairing in Roegneria sinica var. media evaluated using genomic in situ hybridization

The analysis of chromosome pairing during meiosis is important for understanding the relationships between different genomes. To evaluate the diversity of chromosome pairing behavior in the wild species of Roegneria sinica var. media Keng with St and H genomes in Triticeae (Poaceae), differences and similarities in the meiotic chromosome pairing behaviors of the two genomes in two populations of R. sinica var. media, were analyzed using genomic in situ hybridization. Chromosome pairing at meiotic metaphase I in the two populations of R. sinica var. media mainly formed bivalents, although several univalents, trivalents and quadrivalents also occurred. Chromosome pairings occurred mainly between homologous chromosomes. However, some non-homologous pairings were observed under natural conditions. No significant differences in karyotype were found between the St and H genomes. Chromosome pairing behaviors differed between and within the two populations. Genetic variation occurred mainly within populations (94.04 %), and variation was more abundant in one population than the other. The genomes St and H differed, but there was some relationship between the two genomes. These findings suggest that homoeologous pairing of chromosomes or exchanges occurred between different genomes of the wild species in Triticeae during evolution. The findings also provide conclusive cytological evidence for genetic variation within the wild species, which forms the basis of their genetic diversity.

Preferential Y-Y pairing and synapsis and abnormal meiotic recombination in a 47,XYY man with non obstructive azoospermia.

Back groundMen with 47, XYY syndrome are presented with varying physical attributes and degrees of infertility. Little information has been documented regarding the meiotic progression in patients with extra Y chromosome along with the synapses and recombination between the two Y chromosomes.MethodsSpermatocyte spreading and immunostaining were applied to study the behavior of the extra Y chromosome during meiosis I in an azoospermia patient with 47, XYY syndrome and results were compared with five healthy controls with proven fertility.ResultsThe extra Y chromosome was present in all the studied spermatocytes of the patient and preferentially paired and synapsed with the other Y chromosome. Consistently, gamma-H2AX staining completely disappeared from the synapsed regions of Y chromosomes. More interestingly, besides recombination on short arms, recombination on the long arms of Y chromosomes was also observed. No pairing and synapsis defects between homologous autosomes were detected, while significantly reduced recombination frequencies on autosomes were observed in the patient. The meiotic prophase I progression was disturbed with significantly increased proportion of leptotene, zygotene cells and decreased pachytene spermatocytes in the patient when compared with the controls.ConclusionsThese findings highlight the importance of studies on meiotic behaviors in patients with an abnormal chromosomal constitution and provide an important framework for future studies, which may elucidate the impairment caused by extra Y chromosome in mammalian meiosis and fertility.Electronic supplementary materialThe online version of this article (doi:10.1186/s13039-016-0218-z) contains supplementary material, which is available to authorized users.