Closely related sequences on human X and Y chromosomes outside the pairing region

Nature ◽  
1984 ◽  
Vol 311 (5983) ◽  
pp. 259-261 ◽  
Author(s):  
H. J. Cooke ◽  
W. A. R. Brown ◽  
G. A. Rappold
Keyword(s):  
Y Chromosomes ◽  
Pairing Region

The XY Body of the Cat (Felis catus): Structural Differentiations and Protein Immunolocalization

2017 ◽  
Vol 152 (3) ◽  
pp. 137-147 ◽  
Author(s):  
Roberta B. Sciurano ◽  
Geraldine De Luca ◽  
I. Mónica Rahn ◽  
Alberto J. Solari
Keyword(s):  
Sex Chromosome ◽  
Structural Characteristics ◽  
Domestic Cat ◽  
Xy Body ◽  
Meiotic Sex Chromosome Inactivation ◽  
Y Chromosomes ◽  
Extreme Degree ◽  
Special Location ◽  
Pairing Region

The heteromorphic X and Y chromosomes behave in a special way in mammalian spermatocytes; they form the XY body and synapse only partially. The aim of this article was to study the origin and the role of the special differentiations in the XY pair of the domestic cat during pachytene by analyzing its fine structural characteristics and the immunolocalization of the main meiotic proteins SYCP3, SYCP1, SYCE3, SMC3, γ-H2AX, BRCA1, H3K27me3, and MLH1. The cat XY body shows particularly striking structures: an extreme degree of axial fibrillation in late pachynema and a special location of SYCP3-containing fibrils, bridging different regions of the main X axis, as well as one bridge at the inner end of the pairing region that colocalizes with the single mandatory MLH1 focus. There are sequential changes, first bullous expansions, then subdivision into fibrils, all involving axial thickening. The chromatin of the XY body presents the usual features of meiotic sex chromosome inactivation. An analysis of the XY body of many eutherians and metatherians suggests that axial thickenings are primitive features. The sequential changes in the mass and location of SYCP3-containing fibers vary among the clades because of specific processes of axial assembly/disassembly occurring in different species.

scholarly journals UNEQUAL CROSSING OVER AT THE rRNA TANDON AS A SOURCE OF QUANTITATIVE GENETIC VARIATION IN DROSOPHILA

Genetics ◽  
1980 ◽  
Vol 95 (3) ◽  
pp. 727-742 ◽  
Author(s):  
R Frankham ◽  
D A Briscoe ◽  
R K Nurthen
Keyword(s):  
Genetic Variation ◽  
Selection Response ◽  
Crossing Over ◽  
Wild Type ◽  
X Chromosomes ◽  
Unequal Crossing Over ◽  
Quantitative Genetic ◽  
Y Chromosomes ◽  
Homozygous Line ◽  
Minimum Estimate

ABSTRACT Abdominal bristle selection lines (three high and three low) and controls were founded from a marked homozygous line to measure the contribution of sex-linked "mutations" to selection response. Two of the low lines exhibited a period of rapid response to selection in females, but not in males. There were corresponding changes in female variance, in heritabilities in females, in the sex ratio (a deficiency of females) and in fitness, as well as the appearance of a mutant phenotype in females of one line. All of these changes were due to bb alleles (partial deficiencies for the rRNA tandon) in the X chromosomes of these lines, while the Y chromosomes remained wild-type bb+. We argue that the bb alleles arose by unequal crossing over in the rRNA tandon.—A prediction of this hypothesis is that further changes can occur in the rRNA tandon as selection is continued. This has now been shown to occur.—Our minimum estimate of the rate of occurrence of changes at the rRNA tandon is 3 × 10-4. As this is substantially higher than conventional mutation rates, the questions of the mechanisms and rates of origin of new quantitative genetic variation require careful re-examination.

Y Chromosomes in Male Psychiatric Patients above 180 cm. Tall

1968 ◽  
Vol 114 (517) ◽  
pp. 1589-1590 ◽  
Author(s):  
Johannes Nielsen
Keyword(s):  
Chromosome Number ◽  
State Hospital ◽  
Psychiatric Patients ◽  
Chromosome Analysis ◽  
Y Chromosomes ◽  
Sex Chromatin ◽  
Male Patients

All male patients above 180 cm. tall who were resident in the Århus State Hospital on 13 April, 1966, were registered: they numbered 42 out of the total of 440 resident males (8 · 1 per cent.). One patient, a 78-year-old man, died before chromosome analysis was made. Sex-chromatin analysis was made on Feulgenstained buccal smears and chromosome analysis was made on leucocyte cultures according to the method described by Moorhead et al. (1960), slightly modified. Not less than 25 metaphases were counted, at least 15 metaphases with the modal figure and all metaphases with a chromosome number deviating from the modal figures were analysed.

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