XY follicle cells in the ovaries of XO/XY and XO/XY/XYY mosaic mice

XO/XY and XO/XY/XYY mosaic hermaphrodites were generated from crosses involving BALB/cWt males. The distribution of Y-bearing cells in the gonads of these mice was studied by in situ hybridisation using the Y-specific probe pY353B. XY cells were found to contribute to all cell lineages of the ovary including follicle cells. The proportion of XY follicle cells was not significantly different from the XY contribution to other gonadal or non-gonadal cell lineages. However, this proportion was consistently low, all the hermaphrodites having a low XY contribution to the animal as a whole. Because the XO- and Y-bearing cell lineages are developmentally balanced, the XY follicle cells cannot have formed as a result of a 'mismatch' in which the Y-directed testis determination process is pre-empted by an early acting programme of ovarian development. These results are discussed with respect to the hypothesis that Tdy acts in the supporting cell lineage, the lineage from which Sertoli cells and follicle cells are believed to be derived.     

The fate of XO germ cells in the testes of XO/XY and XO/XY/XYY mouse mosaics: evidence for a spermatogenesis gene on the mouse Y chromosome

A cytogenetic and histological study of nine XO/XY or XO/XY/XYY mosaic mice revealed that XO germ cells were selectively eliminated from the spermatogenic epithelium. Although the XO contribution to the bone marrow in seven mice exceeded 50%, in only two cases were significant numbers of dividing XO spermatogonia present. These XO germ cells only occasionally progressed to meiosis and then degenerated prior to first meiotic metaphase. It was concluded that the mouse Y chromosome carries a "spermatogenesis gene" (or genes) which acts autonomously in the germ cells.     

The XYY condition in a wild mammal: an XY/XYY mosaic common shrew (Sorex araneus)

XY/XYY sex-chromosome mosaicism was demonstrated in both bone marrow and germ cells of a wild adult common shrew. Secondary sexual characteristics were those of a normal male, but the testes were small, and the sperm count was only about 3% of normal. Most of the seminiferous tubule cross-sections examined revealed serious spermatogenic impairment and a reduced diameter. A range of sex-chromosome pairing configurations was observed in XYY primary spermatocytes, including configurations involving the X and both Y chromosomes in a linear or radial array. The presence of metaphase II (MII) spreads with an XY sex-chromosome complement indicated that XYY primary spermatocytes could contribute products to MII. Following Burgoyne (1979) and Burgoyne and Biddle (1980), a number of models of spermatocyte loss were tested. The data indicated that there was an association between the sex-chromosome complement of primary spermatocytes and their contribution to MII. The best fit to the observed MII frequency data was provided by a model which assumed that all XYY primary spermatocytes with a univalent Y chromosome and a high proportion of XYY primary spermatocytes with an unpaired X chromosome failed to contribute products to MII.     

A 39,X/40,XY/41,XYY mosaic male mouse

Cytogenetic analyses of bone marrow and gonadal cells in a male mouse, which appeared to be normal, revealed mosaicism in both tissues. Three chromosome complements, 39,X, 40,XY, and 41,XYY, were found in both bone marrow and spermatogonia, while only the last two complements were found in spermatocytes. In this mouse, unlike in the human, the XYY cells showed a proliferative advantage over the XY cells. In XYY cells at diakinesis/metaphase I the gonosomes showed all possible types of association, and a pairing advantage of the X chromosome was clearly demonstrated. The fertility of the mouse was not determined. However, since the epididymal sperm count was reduced by only 55% and the incidence of sperm head abnormality was near normal, it is not evident that the mouse was sterile.     

XO/XY mosaicism in a 2 year phenotypic male.

A 2-year-old male with bilateral undescended gonads, hypoplastic external auditory canals, large umbilical hernia and XO/XY chromosome mosaicism is described in this communication. Salient features of other similar cases, i.e. XO/XY mosaicism in phenotypic males, from the literature are summarized, showing the wide diversity of manifestations of this syndrome.     

XO/XY mosaicism and non-fluorescing Y chromosome in a male

Summary An adult male of short stature and with underdeveloped external genitalia is described, who carried out a number of sexual assaults on young women. He proved to have XO/XY mosaicism and a non-fluorescing Y chromosome. It was considered to be a terminal deletion on morphological grounds. It is suggested, on the evidence of the small number of XO/XY mosaics examined by appropriate staining methods, that an abnormal Y chromosome, whether terminally deleted or non-fluorescing owing to an altered chemical state, predisposes to anaphase lagging and non-disjunction.Of eleven reported cases of XO/XY mosaicism with a non-fluorescing Y chromosome, this is the fifth of male phenotype. The severe behaviour disturbance of early onset is considered to be probably causally associated with the chromosome anomaly.     

Teratogen susceptibility of XO mothers and XO embryos in mice

We examined whether the chromosomal imbalance inherent in an XO constitution in mice is more susceptible to teratogenic influence of biotin deficiency using a newly established mouse colony with pure X monosomy. We hypothesized that XO mothers or XO embryos might be more susceptible to certain teratogens. Contrary to our expectation, the incidence of external malformations induced by biotin deficiency did not differ either between XX dams and XO dams or between XX fetuses and XO fetuses.     

Reversion of XO to XY sex chromosome mechanism in a phasmid

Summary The sex chromosomes of the male phasmid Isagoras schraderi Rehn comprise an X and a Y, — each with a submedian kinetochore, and one euchromatic and one heterochromatic arm. At meiosis X and Y form an unequal sex bivalent in which the euchromatic arms are terminally associated. Relatively recent reversion from the XO-XX mechanism characteristic of the Phasmidae is indicated by the presence of the euchromatic arm in both X and Y. The diploid number of the male is 34.Unequal autosomal bivalents are found at meiosis in two other species of Isagoras — Isagoras subaquiles Rehn and Isagoras sp. — and in Pseudophasma menius Westwood. The chromosome complements of these species are described.     

Chromosome 22 mosaic monosomy (46,XY/45,XY,-22)

A slightly dysmorphic and mentally defective child with mosaic monosomy 22 is reported. Chromosome 22 is absent in 10.5% of lymphocytes and 8.3% of fibroblasts. This is the second case report of that kind.     

X/XY/XYY mosaicism as a cause of subfertility in boars: a single case study

Sex chromosome abnormalities are common in mammals and humans and are often associated with subfertility. In this study a boar with normal sperm parameters was indicated to have reduced prolificacy from figures obtained for return rate, farrowing rate and total number of piglets born. G-banded cytogenetic analysis of peripheral blood identified an abnormal mosaic sex chromosome constitution 39,XYY[74]/38,XY[23]/37,X[3]. Cytogenetic analysis of fibroblasts confirmed this mosaic karyotype with similar percentages of cell lines observed 39,XYY[76]/38,XY[19]/37,X[5]. External genitalia revealed a poorly developed scrotum with the right testicle being smaller than the left. To the best of our knowledge this is the first time that this chromosome constitution has been reported in the pig. It is of particular interest that this karyotype is associated with reduced boar fertility, which could lead to potential economic losses if such a boar were selected for breeding purposes.     

A mosaic XY1Y2/XY1Y2Y2 common shrewSorex araneus

XY₁Y₂/XY₁Y₂Y₂ mosaicism was found in a wild adult common shrewSorex araneus (Linnaeus, 1758) in lymphocytes from spleen. The multiple sex chromosome system in the common shrew was the result of an X-autosome translocation and the Y₂ chromosome was the unpaired autosome present in males. The external phenotype of the shrew was that of a mormal male. The histological picture of its testis showed complete spermatogenic breakdown on the stage of primary spermatocytes, hence the shrew was sterile. The possible causes of spermatogenic arrest in a mosaic shrew are dis cussed.     

Spermatogenesis in XY, XYSxra and XOSxra mice: a quantitative analysis of spermatogenesis throughout puberty

Adult XYSxra mice exhibit varying degrees of spermatogenic deficiency but are usually fertile, while XOSxra mice have severe spermatogenic failure and are always sterile. The present quantitative spermatogenic analysis documents when these anomalies first appear during puberty. The results demonstrate that in XYSxra mice there was increased degeneration of pachytene spermatocytes and, to a lesser extent, meiotic metaphase stages. On average, there were only one-half the number of spermatids compared with the XY controls. The defect in XOSxra mice appeared a little later, with an almost complete arrest and degeneration during the meiotic metaphases, so that the number of spermatids produced was only 3% of the control value. These results are discussed in relation to an hypothesis that links sex chromosome univalence during meiotic prophase with spermatogenic failure.     

Synaptonemal complex studies in a mosaic 46,XY/47,XXY male

Summary We describe the results of synaptonemal complex (SCs) studies by light (LM) and electron microscopy (EM) in a sterile 46,XY/47,XXY male mosaic. Meiotic studies showed an arrest at the first spermatocyte level. Pachytene figures showed three types of cells: (1) cells with normal SCs, normal sex vesicle, and a 23,XY constitution; (2) cells with no sex vesicle, normal pairing of SCs, and a 24, (?) constitution; and (3) cells with a normal sex vesicle and fragmented SCs.     

Meiotic studies of a 38,XY/39,XXY mosaic boar

Klinefelter's syndrome (KS) is the most common sex chromosome abnormality identified in human males. This syndrome is generally associated with infertility. Men with KS may have a 47,XXY or a 46,XY/47,XXY karyotype. Studies carried out in humans and mice suggest that only XY cells are able to enter and complete meiosis. These cells could originate from the XY cells present in mosaic patients or from XXY cells that have lost one X chromosome. In pig, only 3 cases of pure 39,XXY have been reported until now, and no meiotic analysis was carried out. For the first time in pig species we report the analysis of a 38,XY/39,XXY boar and describe the origin of the supplementary X chromosome and the chromosomal constitutions of the germ and Sertoli cells.     

Das XO/XY-Geschlechtschromosomenmosaik

Zusammenfassung Ein Kleinkind mit intersexuellem Genitale, descendierter linker Gonade und einem Uterus zeigte bei der chromosomalen Untersuchung ein XO/XY-Mosaik. Diese Chromosomenmutation stellt eine relativ häufige Intersexform dar, deren Phänotyp erfahrungsgemäß sehr variabel ist. An Hand von 43 Beobachtungen in der Literatur werden Krankheitsbild und Differentialdiagnose des XO/XY-Mosaiks sowie seine Prognose hinsichtlich Pubertät, Fertilität, Körperwachstum und tumoröser Entartung der Gonaden zusammengestellt und Richtlinien für die Therapie vorgeschlagen. Eine frühzeitige Abgrenzung des XO/XY-Mosaiks gegen die inkomplete Form der testiculären Feminisierung ist in prognostischer und therapeutischer Hinsicht notwendig. Die Ätiologie des XO/XY-Mosaiks wird kurz besprochen.

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The XO/XY sex chromosome mosaicism

Summary A child with ambiguous external genitals, descended right gonad and uterus is described. The investigation of the chromosomes showed a XO/XY mosaicism. This chromosomal abnormality is a common type of intersexuality. The phenotype is quite variable. Based on 43 cases in the literature clinical picture and differential diagnosis of XO/XY mosaicism are presented. The prognosis with regard to puberty, fertility, growth and tumors of the gonads is discussed. Headlines for the therapy are given. An early differential diagnosis between XO/XY mosaicism and the incomplete form of testicular feminisation is important because of different prognosis and therapy. The etiology of XO/XY mosaicism is discussed.

     

XY body formation during rat spermatogenesis: an immunocytochemical study using antibodies against XY body-associated proteins

The process of formation of the XY body during meiotic prophase was investigated by immunocytochemistry on cryosections of pubertal rat testes using antibodies against three different XY body-associated proteins. Here we show that these proteins are detectable at only partially overlapping temporal windows. These findings provide the first evidence that the previously described morphological changes in the structure of the XY body that occur during meiotic prophase are accompanied by considerable changes in its protein composition. Received: 22 May 1997 / Accepted: 14 June 1997