Under what circumstances is the human XY bivalent tangled? A note on chromosomally-derived sterility

1987 ◽  
Vol 45 (1) ◽  
pp. 58-61 ◽  
Author(s):  
A. Rosenmann ◽  
J. Wahrman ◽  
C. Richler ◽  
I. Madgar ◽  
R. Weissenberg ◽  
...  
Keyword(s):  
Xy Bivalent

scholarly journals Studies on Metatherian Sex Chromosomes. IX. Sex Chromosomes of the Greater Glider (Marsupialia : Petauridae)

1979 ◽  
Vol 32 (3) ◽  
pp. 375 ◽  
Author(s):  
JD Murray ◽  
GM McKay ◽  
GB Sharman
Keyword(s):  
X Chromosome ◽  
Sex Chromosomes ◽  
National Park ◽  
Secondary Constriction ◽  
X Chromosomes ◽  
Cultured Fibroblasts ◽  
Multiple Sex Chromosomes ◽  
Eastern Australia ◽  
Xy Bivalent ◽  
Secondary Constrictions

The greater glider, currently but incorrectly known as Schoinobates vo/ans, is widely distributed in forested regions in eastern Australia. All animals studied from six different localities had 20 autosomes but there were four chromosomally distinct populations. At Royal National Park, N.S.W., all female greater gliders studied had 22 chromosomes including two large submetacentric X chromosomes with subterminal secondary constrictions in their longer arms. This form of X chromosome occurred also at Bondo State Forest, Myall Lakes and Coff's Harbour, N.S.W., and at Eidsvold, Qld. At Coomooboolaroo, Qld, the X chromosome was also a large submetacentric but a secondary constriction occurred in the shorter arm. Two chromosomally distinct types apparently occur in Royal National Park, one with XY m,ales as in all other populations, and one with XY1Y2 males. Y or Yb but not Y 2, chromosomes were eliminated from the bone marrow in all populations but were present in spermatogonia, primary sperrnatocytes and cultured fibroblasts. Animals from Bondo State Forest had three or more acrocentric or metacentric supernumerary chromosomes. [Other keywords: C-banding, eytotaxonomy, multiple sex chromosomes, XY bivalent.]

scholarly journals Sex chromosome configurations in pachytene spermatocytes of an XYY mouse

1990 ◽  
Vol 56 (2-3) ◽  
pp. 129-133 ◽  
Author(s):  
Charles Tease
Keyword(s):  
Sex Chromosomes ◽  
Male Mouse ◽  
Sex Chromosome ◽  
Chromosome Constitution ◽  
Sterile Male ◽  
Xy Bivalent ◽  
Pachytene Spermatocytes ◽  
Metaphase I

SummaryKaryotypic investigation of a phenotypically normal but sterile male mouse showed the presence of an XYY sex chromosome constitution. The synaptic behaviour of the three sex chromosomes was examined in 65 pachytene cells. The sex chromosomes formed a variety of synaptic configurations: an XYY trivalent (40%); an XY bivalent and Y univalent (38·5%); an X univalent and YY bivalent (13·8%); or X, Y, Y univalence (7·7%). There was considerable variation in the extent of synapsis and some of the associations clearly involved nonhomologous pairing. These observations have been compared with previously published information on chromosome configurations at metaphase I from other XYY males.

scholarly journals Hexavalents in spermatocytes of Robertsonian heterozygotes between Mus m. domesticus 2n=26 from the Vulcano and Lipari Islands (Aeolian Archipelago, Italy)

2018 ◽  
Author(s):  
Soledad Berríos ◽  
Raúl Fernández-Donoso ◽  
Jesús Page ◽  
Eliana Ayarza ◽  
Ernesto Capanna ◽  
...  
Keyword(s):  
X Chromosome ◽  
Nuclear Architecture ◽  
Mus Musculus Domesticus ◽  
Open Chain ◽  
Telocentric Chromosome ◽  
Telocentric Chromosomes ◽  
Xy Bivalent ◽  
Chromosomal Changes ◽  
A Chain ◽  
Pachytene Spermatocytes

The size and shape of the chromosomes, as well as the chromosomal domains that compose them, are determinants in the distribution and interaction between the bivalents within the nucleus of spermatocytes in prophase I of meiosis. Thus the nuclear architecture characteristic of the karyotype of a species can be modified by chromosomal changes such as Rb chromosomes. In this study we analysed the meiotic prophase nuclear organization of the heterozygous spermatocytes from Mus musculus domesticus 2n=26, and the synaptic configuration of the hexavalent formed by the dependent Rb chromosomes Rbs 6.16, 16.10, 10.15, 15.17 and the telocentric chromosomes 6 and 17. Spreads of 88 pachytene spermatocytes from two males were studied and in all of them five metacentric bivalents, four telocentric bivalents, one hexavalent and the XY bivalent were observed. About 48% of the hexavalents formed a chain or a ring of synapsed chromosomes, the latter closed by synapsis between the short arms of telocentric chromosomes 6 and 17.  About 52% of hexavalents formed an open chain of 10 synapsed chromosomal arms belonging to 6 chromosomes.  In about half of the unsynapsed hexavalents one of the telocentric chromosome short arms appears associated with the X chromosome single axis, which was otherwise normally paired with the Y chromosome.  The cluster of pericentromeric heterochromatin mostly determines the hexavalent’s nuclear configuration, dragging the centromeric regions and all the chromosomes towards the nuclear envelope similar to an association of five telocentric bivalents. These reiterated encounters between these chromosomes restrict the interactions with other chromosomal domains and might favour eventual rearrangements within the metacentric, telocentric or hexavalent chromosome subsets. The unsynapsed short arms of telocentric chromosomes frequently bound to the single axis of the X chromosome could further complicate the already complex segregation of hexavalent chromosomes.

Morphological and temporal sequence of meiotic prophase development at puberty in the male mouse

1984 ◽  
Vol 65 (1) ◽  
pp. 249-263
Author(s):  
P. Goetz ◽  
A.C. Chandley ◽  
R.M. Speed
Keyword(s):  
Synaptonemal Complex ◽  
Adult Male ◽  
Meiotic Prophase ◽  
Male Mouse ◽  
Late Pachytene ◽  
Diplotene Stage ◽  
Y Chromosomes ◽  
Correct Sequence ◽  
Xy Bivalent ◽  
Morphological Detail

The correct sequence of meiotic prophase development in the male mouse has been established by the use of pubertal males. The first wave of spermatogenesis at this time provides a unique opportunity to study progressive meiotic development in a direct way. Air-dried and micro-spread analyses have been carried out. Temporal and morphological progression at this time is entirely consistent with that occurring in the later waves of meiosis of the adult male. Morphological detail shows delayed pairing of the X and Y chromosomes relative to the autosomes. The longest XY synaptonemal complex is seen in early pachytene cells, occupying up to 72% of the length of the Y and 22% of the length of the X axis. By late pachytene, end-to-end pairing in the XY bivalent is established, the autosomal axes remaining fully paired. Desynapsis of the autosomes commences at early diplotene. A ‘diffuse’ diplotene stage in the male, comparable to the dictyate stage of the female, could not be found. Marked lengthening of the XY and autosomal axes did, however, occur through the diplotene stage.

scholarly journals Ring XY bivalent: a new phenomenon at metaphase I of meiosis in man.

1987 ◽  
Vol 24 (2) ◽  
pp. 101-106 ◽  
Author(s):  
A C Chandley ◽  
T B Hargreave ◽  
S McBeath ◽  
A R Mitchell ◽  
R M Speed
Keyword(s):  
Xy Bivalent ◽  
Metaphase I

Extensive pairing of the XY bivalent in mouse spermatocytes as visualized by whole-mount electron microscopy

1977 ◽  
Vol 25 (1) ◽  
pp. 1-15
Author(s):  
L.L. Tres
Keyword(s):  
Sex Chromosomes ◽  
Detergent Solution ◽  
Lateral Element ◽  
Synaptonemal Complexes ◽  
Pairing Segment ◽  
Y Chromosomes ◽  
Cell Dispersion ◽  
Whole Mount ◽  
Xy Bivalent ◽  
Microscope Technique

Autosomes and sex chromosomes of mouse spermatocytes were examined during zygotene, pachytene, and diplotene by a whole-mount electron-microscope technique after cell dispersion in a detergent solution (Nonidet-P40). Zygotene, pachytene, and diplotene stages can be adequately identified in the preparations. Thus, asynchronous side-by-side pairing of homologous autosomes, some of them displaying attached nucleoli, defines zygotene. Pachytene is identified by complete pairing of homologues. Diplotene is characterized by disjunction of bivalents (autosomes and sex chromosomes), lack of autosomal-attached nucleoli, divergent expansions observed at lateral element endings of disassembled synaptonemal complexes, end-to-end association of the XY pair and well defined outward deformations (‘bulges’) along sex chromosomal axial cores. X and Y chromosomes display at pachytene an extensive side-by-side pairing segment which decreases in length as meiotic prophase advances. Each sex chromosomal axial core appears double and is formed by close apposition of 2 nearly parallel elements displayed separately along the entire length of the chromosomal core. This double structural feature suggests that each sex chromosomal axial core is presumably composed of 2 chromatid axial cores, each of which, in turn, constitutes the respective lateral elements of short synaptonemal complexes observed at the unpaired segment.

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