scholarly journals An Infertile Azoospermic Male with 45, X T(Yp;15) Karyotype

Author(s):  
Maryam Abi ◽  
Maryam Hassanlou ◽  
Nima Narimani ◽  
Marzieh Zamani ◽  
Zahra Moeini

Objective: 45, X is a very rare condition that usually results from Y/autosomal translocations or insertions. Here we present an infertile azoospermic man who had 45, X t(Yp;15) karyotype and deletion of AZF (azoospermia factor) gene region. Case report: A 35-year-old infertile azoospermic man with a typical male appearance came for infertility genetic counseling. He was infertile for more than ten years and had short height. High-resolution of metaphase chromosomes of 50 peripheral white blood cells were analyzed for karyotyping. Fluorescence in situ hybridization (FISH) analysis and Polymerase chain reaction (PCR) were done for SRY and AZF gene localization. Karyotyping and FISH analysis revealed 45, X t(Yp;15) karyotype and no mosaicism. More investigation on the Y chromosome revealed no deletion in the SRY region, but AZF a/b/c were deleted. It was revealed that Yp's subtelomeric region but not Yq was translocated to chromosome 15. Conclusion: This study shows that despite the lack of a complete Y chromosome in this person, the occurrence of secondary male traits is a result of the short arm translocation of the Y chromosome, which contains the (ex-determining region Y) SRY gene. Infertility is also due to the Y chromosomes long arm's deletion containing the AZF gene region.  

2009 ◽  
Vol 21 (1) ◽  
pp. 229 ◽  
Author(s):  
B. A. Didion ◽  
R. Bleher

Flow cytometric separation of X- and Y-chromosome bearing bovine sperm is an accepted technology for use at the commercial level. Nevertheless it is important to continue researching the area of gender-preselected sperm for improved efficiencies. We used a synthetic DNA mimic conjugated to a fluorescent dye for in situ detection of Y chromosomes in metaphase preparations of bovine somatic cells and spermatozoa. Peptide nucleic acids (PNA) are a type of DNA mimic having a higher affinity and stability than conventional DNA probes and are used as hybridization probes to complementary DNA. Using male bovine somatic cells and the Y-chromosome as a template, we arranged for the synthesis of a CY3-conjugated PNA to bind 13 to 15 base pairs of unique, Y-chromosome sequence. By testing different labeling conditions, we found that brief incubation (~1 h) of metaphase chromosomes with the PNA produced a localized signal on the Y-chromosome. No signals were observed when chromosomes of female bovine somatic cells were incubated with the same PNA probe. Because chromosomes occupy non-random territories in all cell nuclei, including sperm, we proposed to find centrally-located signals in 50% of fixed bovine sperm when treated with the same PNA as used for the somatic cells. As expected, we found the PNA signals present in 50% sperm (23/43) existing as a single, centrally-located, round fluorescent dot in the sperm head. Validation studies were also conducted using bovine sperm previously flow sorted into X or Y populations, and we found the signals in accordance to an expected signal present using the PNA (146/165 or 88.5% with PNA signal in presorted Y sperm heads and 13/174 or 7.5% with PNA signal in presorted X sperm heads).


1995 ◽  
Vol 4 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Ann C Chandley

Amongst men who attend fertility problems clinics, just over 10% are diagnosed to be oligospermic (< 5 × 106 sperm per ml) or azoospermic, with no known aetiological explanation. Amongst the many possible causes of impaired sperm production there is a genetic component, a pointer to the possible location of some of the responsible genes being found in 1976 when Tiepolo and Zuffardi discovered six azoospermic individuals with a deleted Y chromosome. In each individual, the long arm of the Y chromosome had lost its distal fluorescent segment as well as part of the nonfluorescent euchromatin lying proximal to it (Figure 1). They hypothesized that factors important in spermatogenesis might lie at the interface between fluorescent and nonfluorescent material. The locus, AZFor ‘azoospermia factor’, was subsequently mapped, using collections of deleted Y chromosomes, to interval six of the long arm and it lies within cytological band Yq11.23 (Figure 2).


2021 ◽  
Author(s):  
Shengfang Qin ◽  
Zhuo Zhang ◽  
Ximin Chen ◽  
Yan Yin ◽  
Mengling Ye ◽  
...  

Abstract BackgroundA rare disease is that an individual with a non-chimeric karyotype of 45, X develops into a male. We explored the genetic aetiology of an infertility male with an apparent 45, X karyotype, which was subsequently verified as cryptic translocation between chromosomes Y and 15. MethodsPeripheral blood sample was collected from the patient and subjected to a range of genetic testing, including conventional chromosomal karyotyping, short tandem repeat (STR) analysis for azoospermia factor (AZF) region, fluorescence in situ hybridization (FISH) with specific probes for CSP X/CSP Y, CSP Y/D15Z1/PML and SRY/D15Z1/PML, and chromosomal microarray analysis (CMA) for genomic copy number variations (CNVs). ResultsThe patient was found to have an apparent 45,X karyotype. STR analysis showed that he possessed a short arm of the Y chromosome, including the SRY gene but the absence of a long arm of the Y chromosome, including AZFa+b+c and Yqter. A FISH assay using CSP X and CSP Y probes showed a green signal at the centromere of the X chromosome and a red signal for the Y centromeric sequence on a D-group-sized chromosome. By FISH assaying with D15Z1 and CSP Y probes, chromosomes 15 and Y centromeric signals appeared closely on a single chromosome, as ascertained by the PML control probe. A further FISH assay with D15Z1 and SRY probes revealed a signal of the SRY gene at the end of one arm of chromosome 15. The result of the CMA indicated a deletion with an approximate size of 45.31 Mb spanning from Yq11 to Yter. ConclusionAlthough the 45,X male patient did not harbour an intact Y chromosome, his genome contained the SRY gene derived from the translocation of the Yp, which probably triggered the male differentiation and development. Imbalanced translocations of Yp to other chromosomes can result in short stature and infertility among patients. Delineation of the genetic aetiology can guide early intervention and assisted reproduction in adulthood.


Genetics ◽  
1989 ◽  
Vol 122 (3) ◽  
pp. 617-624 ◽  
Author(s):  
S M Williams ◽  
J A Kennison ◽  
L G Robbins ◽  
C Strobeck

Abstract The role of reciprocal recombination in the coevolution of the ribosomal RNA gene family on the X and Y chromosomes of Drosophila melanogaster was assessed by determining the frequency and nature of such exchange. In order to detect exchange events within the ribosomal RNA gene family, both flanking markers and restriction fragment length polymorphisms within the tandemly repeated gene family were used. The vast majority of crossovers between flanking markers were within the ribosomal RNA gene region, indicating that this region is a hotspot for heterochromatic recombination. The frequency of crossovers within the ribosomal RNA gene region was approximately 10(-4) in both X/X and X/Y individuals. In conjunction with published X chromosome-specific and Y chromosome-specific sequences and restriction patterns, the data indicate that reciprocal recombination alone cannot be responsible for the observed variation in natural populations.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Lingzhan Xue ◽  
Yu Gao ◽  
Meiying Wu ◽  
Tian Tian ◽  
Haiping Fan ◽  
...  

Abstract Background The origin of sex chromosomes requires the establishment of recombination suppression between the proto-sex chromosomes. In many fish species, the sex chromosome pair is homomorphic with a recent origin, providing species for studying how and why recombination suppression evolved in the initial stages of sex chromosome differentiation, but this requires accurate sequence assembly of the X and Y (or Z and W) chromosomes, which may be difficult if they are recently diverged. Results Here we produce a haplotype-resolved genome assembly of zig-zag eel (Mastacembelus armatus), an aquaculture fish, at the chromosomal scale. The diploid assembly is nearly gap-free, and in most chromosomes, we resolve the centromeric and subtelomeric heterochromatic sequences. In particular, the Y chromosome, including its highly repetitive short arm, has zero gaps. Using resequencing data, we identify a ~7 Mb fully sex-linked region (SLR), spanning the sex chromosome centromere and almost entirely embedded in the pericentromeric heterochromatin. The SLRs on the X and Y chromosomes are almost identical in sequence and gene content, but both are repetitive and heterochromatic, consistent with zero or low recombination. We further identify an HMG-domain containing gene HMGN6 in the SLR as a candidate sex-determining gene that is expressed at the onset of testis development. Conclusions Our study supports the idea that preexisting regions of low recombination, such as pericentromeric regions, can give rise to SLR in the absence of structural variations between the proto-sex chromosomes.


2006 ◽  
Vol 44 (3) ◽  
pp. 205-208 ◽  
Author(s):  
B. Arredi ◽  
A. Ferlin ◽  
E. Speltra ◽  
C. Bedin ◽  
D. Zuccarello ◽  
...  

Genetics ◽  
2003 ◽  
Vol 163 (1) ◽  
pp. 245-251 ◽  
Author(s):  
Indrajit Nanda ◽  
Ute Hornung ◽  
Mariko Kondo ◽  
Michael Schmid ◽  
Manfred Schartl

Abstract In the medaka, a duplicated version of the dmrt1 gene, dmrt1bY, has been identified as a candidate for the master male sex-determining gene on the Y chromosome. By screening several strains of Northern and Southern medaka we identified a considerable number of males with normal phenotype and uncompromised fertility, but lacking dmrt1bY. The frequency of such males was &gt;10% in some strains and zero in others. Analysis for the presence of other Y-linked markers by FISH analysis, PCR, and phenotype indicated that their genotype is XX. Crossing such males with XX females led to a strong female bias in the offspring and also to a reappearance of XX males in the following generations. This indicated that the candidate male sex-determining gene dmrt1bY may not be necessary for male development in every case, but that its function can be taken over by so far unidentified autosomal modifiers.


Genetics ◽  
2021 ◽  
Author(s):  
Takahiro Sakamoto ◽  
Hideki Innan

Abstract Muller’s ratchet is a process in which deleterious mutations are fixed irreversibly in the absence of recombination. The degeneration of the Y chromosome, and the gradual loss of its genes, can be explained by Muller’s ratchet. However, most theories consider single-copy genes, and may not be applicable to Y chromosomes, which have a number of duplicated genes in many species, which are probably undergoing concerted evolution by gene conversion. We developed a model of Muller’s ratchet to explore the evolution of the Y chromosome. The model assumes a non-recombining chromosome with both single-copy and duplicated genes. We used analytical and simulation approaches to obtain the rate of gene loss in this model, with special attention to the role of gene conversion. Homogenization by gene conversion makes both duplicated copies either mutated or intact. The former promotes the ratchet, and the latter retards, and we ask which of these counteracting forces dominates under which conditions. We found that the effect of gene conversion is complex, and depends upon the fitness effect of gene duplication. When duplication has no effect on fitness, gene conversion accelerates the ratchet of both single-copy and duplicated genes. If duplication has an additive fitness effect, the ratchet of single-copy genes is accelerated by gene duplication, regardless of the gene conversion rate, whereas gene conversion slows the degeneration of duplicated genes. Our results suggest that the evolution of the Y chromosome involves several parameters, including the fitness effect of gene duplication by increasing dosage and gene conversion rate.


2018 ◽  
Vol 156 (4) ◽  
pp. 179-184
Author(s):  
Vida Čulić ◽  
Ruzica Lasan-Trcić ◽  
Thomas Liehr ◽  
Igor N. Lebedev ◽  
Maja Pivić ◽  
...  

We report a case of familial small supernumerary marker chromosome 15 in a phenotypically normal female with 4 recurrent spontaneous abortions and a healthy child. The initial karyotype showed a small, bisatellited, apparently metacentric marker chromosome, 47,XX,+idic(15)(q11.1), maternally inherited. The proband's mother was mosaic for the idic(15)(q11.1) without pregnancy loss. Reexamination of the proband's karyotype revealed cryptic mosaicism for 1 ring and 1 minute chromosome derived de novo from chromosome 9 in 2% of the metaphases. In FISH analysis, the patient's karyotype was mos 47,XX,+idic(15)(q11.1)mat[100]/49,XX,+idic(15)(q11.1)mat,+r(9;9;9;9),+der(9)dn[2]. The second spontaneous abortion had trisomy 9 (47,XX,+9); the third had mosaic trisomy 9 in 21% of the nuclei and isodicentric chromosome 15 in 36% of the nuclei (mos 48,XN,+9,+idic(15)(q11.1)/47,XN,+9/47,XN,+idic(15)(q11.1)/46,XN). The first and fourth abortions were not cytogenetically studied. The cause of the spontaneous abortions in this patient is likely the cryptic mosaicism for ring and minute chromosomes 9, and gonadal mosaicism is most probable, due to the 2 abortions.


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