scholarly journals High rate of recombination and double crossovers in the mouse pseudoautosomal region during male meiosis.

1987 ◽  
Vol 84 (20) ◽  
pp. 7218-7220 ◽  
Author(s):  
P. Soriano ◽  
E. A. Keitges ◽  
D. F. Schorderet ◽  
K. Harbers ◽  
S. M. Gartler ◽  
...  
Keyword(s):  
Male Meiosis ◽  
High Rate ◽  
Pseudoautosomal Region ◽  
Double Crossovers

Sex Chromosomes and Psychosis

1988 ◽  
Vol 153 (5) ◽  
pp. 675-683 ◽  
Author(s):  
T. J. Crow
Keyword(s):  
Sex Chromosomes ◽  
Distal Segment ◽  
Depressive Illness ◽  
Male Meiosis ◽  
High Rate ◽  
Pseudoautosomal Region ◽  
Psychiatric Disease ◽  
Same Sex ◽  
Y Chromosomes ◽  
Gender Influences

Although the incidence of the recurrent psychoses (bipolar affective illness and schizophrenia) in the two sexes is approximately equal, gender influences a number of aspects of major psychiatric disease: unipolar depressive illness is twice as common in females, onset of schizophrenia is earlier and outcome is worse in males, and pairs of psychotic first-degree relatives are more often than expected of the same sex. In addition, sex chromosomal aneuploidies (e.g. XXY and XXX) are more frequent in patients with psychosis. Some of these findings can be explained if there is a major locus of predisposition to psychiatric disease in the ‘pseudoautosomal’ region of the sex chromosomes – that distal segment of the short arms in which there is genetic exchange between X and Y chromosomes at male meiosis. A gene located here would be transmitted in an autosomal manner, but would be passed above chance expectation to children of the same sex when inherited through a male. In that this segment of the sex chromosomes is subject to a high rate of recombination (which could generate new mutations), and may include determinants of brain lateralisation, it appears that the pseudoautosomal region could carry the genes which predispose to the major psychoses.

scholarly journals Human Spermatogenesis Tolerates Massive Size Reduction of the Pseudoautosomal Region

2020 ◽  
Vol 12 (11) ◽  
pp. 1961-1964
Author(s):  
Maki Fukami ◽  
Yasuko Fujisawa ◽  
Hiroyuki Ono ◽  
Tomoko Jinno ◽  
Tsutomu Ogata
Keyword(s):  
Animal Studies ◽  
Male Meiosis ◽  
Size Reduction ◽  
Pseudoautosomal Region ◽  
Minimal Size ◽  
Y Chromosomes ◽  
Cytogenetic Analyses ◽  
Human Spermatogenesis ◽  
Complete Deletion ◽  
Chromosomal Recombination

Abstract Mammalian male meiosis requires homologous recombination between the X and Y chromosomes. In humans, such recombination occurs exclusively in the short arm pseudoautosomal region (PAR1) of 2.699 Mb in size. Although it is known that complete deletion of PAR1 causes spermatogenic arrest, no studies have addressed to what extent male meiosis tolerates PAR1 size reduction. Here, we report two families in which PAR1 partial deletions were transmitted from fathers to their offspring. Cytogenetic analyses revealed that a ∼400-kb segment at the centromeric end of PAR1, which accounts for only 14.8% of normal PAR1 and 0.26% and 0.68% of the X and Y chromosomes, respectively, is sufficient to mediate sex chromosomal recombination during spermatogenesis. These results highlight the extreme recombinogenic activity of human PAR1. Our data, in conjunction with previous findings from animal studies, indicate that the minimal size requirement of mammalian PARs to maintain male fertility is fairly small.

scholarly journals Molecular Cytogenetic and Y Copy Number Analysis of a Reciprocal ECAY-ECA13 Translocation in a Stallion with Complete Meiotic Arrest

Genes ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1892
Author(s):  
Caitlin Castaneda ◽  
Agustin J. Ruiz ◽  
Ahmed Tibary ◽  
Terje Raudsepp
Keyword(s):  
Copy Number ◽  
Genetic Material ◽  
Single Copy ◽  
Male Meiosis ◽  
Pseudoautosomal Region ◽  
Derivative Chromosome ◽  
Meiotic Arrest ◽  
Molecular Cytogenetic ◽  
Multicopy Genes ◽  
Chromosome 13Q

We present a detailed molecular cytogenetic analysis of a reciprocal translocation between horse (ECA) chromosomes Y and 13 in a Friesian stallion with complete meiotic arrest and azoospermia. We use dual-color fluorescence in situ hybridization with select ECAY and ECA13 markers and show that the translocation breakpoint in ECAY is in the multicopy region and in ECA13, at the centromere. One resulting derivative chromosome, Y;13p, comprises of ECAY heterochromatin (ETSTY7 array), a small single copy and partial Y multicopy region, and ECA13p. Another derivative chromosome 13q;Y comprises of ECA13q and most of the single copy ECAY, the pseudoautosomal region and a small part of the Y multicopy region. A copy number (CN) analysis of select ECAY multicopy genes shows that the Friesian stallion has significantly (p < 0.05) reduced CNs of TSPY, ETSTY1, and ETSTY5, suggesting that the translocation may not be completely balanced, and genetic material is lost. We discuss likely meiotic behavior of abnormal chromosomes and theorize about the possible effect of the aberration on Y regulation and the progression of meiosis. The study adds a unique case to equine clinical cytogenetics and contributes to understanding the role of the Y chromosome in male meiosis.

scholarly journals Distinct Properties of the XY Pseudoautosomal Region Crucial for Male Meiosis

Science ◽  
2011 ◽  
Vol 331 (6019) ◽  
pp. 916-920 ◽  
Author(s):  
L. Kauppi ◽  
M. Barchi ◽  
F. Baudat ◽  
P. J. Romanienko ◽  
S. Keeney ◽  
...  
Keyword(s):  
Male Meiosis ◽  
Pseudoautosomal Region

scholarly journals Evolutionary dynamics of pseudoautosomal region 1 in humans and great apes

2021 ◽  
Author(s):  
Juraj Bergman ◽  
Mikkel Heide Schierup
Keyword(s):  
Sex Chromosomes ◽  
Evolutionary Dynamics ◽  
Mutagenic Effect ◽  
Great Apes ◽  
Strand Break ◽  
Male Meiosis ◽  
Pseudoautosomal Region ◽  
Telomeric Region ◽  
Male Recombination ◽  
Telomeric Sequences

The pseudoautosomal region 1 (PAR1) is a 2.7 Mb telomeric region of human sex chromosomes. As the largest point of contact between the X and Y, PAR1 has a crucial role in ensuring proper segregation of sex chromosomes during male meiosis, exposing it to extreme recombination and associated mutational processes. We investigate PAR1 evolution using population genomic datasets of extant humans, eight populations of great apes and two archaic human genome sequences. We find that the PAR1 sequence is closer to nucleotide equilibrium than autosomal telomeric sequences. We detect a difference between long-term substitution patterns and extant diversity in PAR1 that is mainly driven by the conflict between strong mutation and recombination-associated fixation bias at CpG sites. Additionally, we detect excess C→G mutations in PAR1 of all great ape species, specific to the mutagenic effect of male recombination. Analysis of differences between frequencies of alleles segregating in females and males provided no evidence for sexually antagonistic selection in this region. Furthermore, despite recent evidence for Y chromosome introgression from humans into Neanderthals, we find that the Neanderthal PAR1 retained similarity to the Denisovan sequence, as is the case for the X chromosome and the autosomes. Lastly, we study repeat content and double-strand break hotspot regions in PAR1 and find that they may play roles in ensuring the obligate X-Y recombination event during male meiosis. Our study provides an unprecedented quantification of population genetic forces and insight into evolutionary processes governing PAR1 biology.

Normal and abnormal interchanges between the human X and Y chromosomes

Development ◽  
1987 ◽  
Vol 101 (Supplement) ◽  
pp. 67-74
Author(s):  
Jean Weissenbach ◽  
Jacqueline Levilliers ◽  
Christine Petit ◽  
François Rouyer ◽  
Marie-Christine Simmler
Keyword(s):  
Male Meiosis ◽  
Pseudoautosomal Region ◽  
Female Meiosis ◽  
Recombination Activity ◽  
Crossover Point ◽  
X Chromosomes ◽  
Chi Sequence ◽  
Recombination Hotspots ◽  
Y Chromosomes ◽  
Recombination Mapping

A single obligatory recombination event takes place at male meiosis in the tips of the X- and Y-chromosome short arms (i.e. the pseudoautosomal region). The crossover point is at variable locations and thus allows recombination mapping of the pseudoautosomal loci along a gradient of sex linkage. Recombination at male meiosis in the terminal regions of the short arms of the X and Y chromosomes is 10- to 20-fold higher than between the same regions of the X chromosomes during female meiosis. The human pseudoautosomal region is rich in highly polymorphic loci associated with minisatellites. However, these minisatellites are unrelated to those resembling the bacterial Chi sequence and which possibly represent recombination hotspots. The high recombination activity of the pseudoautosomal region at male meiosis sometimes results in unequal crossover which can generate various sex-reversal syndromes.

scholarly journals The Location of the Pseudoautosomal Boundary in Silene latifolia

Genes ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 610
Author(s):  
Marc Krasovec ◽  
Yu Zhang ◽  
Dmitry A. Filatov
Keyword(s):  
Genetic Map ◽  
Sex Chromosomes ◽  
Male Meiosis ◽  
Silene Latifolia ◽  
Pseudoautosomal Region ◽  
Wild Populations ◽  
Y Chromosomes ◽  
Polymorphism Data ◽  
Fuzzy Boundary ◽  
Over Time

Y-chromosomes contain a non-recombining region (NRY), and in many organisms it was shown that the NRY expanded over time. How and why the NRY expands remains unclear. Young sex chromosomes, where NRY expansion occurred recently or is on-going, offer an opportunity to study the causes of this process. Here, we used the plant Silene latifolia, where sex chromosomes evolved ~11 million years ago, to study the location of the boundary between the NRY and the recombining pseudoautosomal region (PAR). The previous work devoted to the NRY/PAR boundary in S. latifolia was based on a handful of genes with locations approximately known from the genetic map. Here, we report the analysis of 86 pseudoautosomal and sex-linked genes adjacent to the S. latifolia NRY/PAR boundary to establish the location of the boundary more precisely. We take advantage of the dense genetic map and polymorphism data from wild populations to identify 20 partially sex-linked genes located in the “fuzzy boundary”, that rarely recombines in male meiosis. Genes proximal to this fuzzy boundary show no evidence of recombination in males, while the genes distal to this partially-sex-linked region are actively recombining in males. Our results provide a more accurate location for the PAR boundary in S. latifolia, which will help to elucidate the causes of PAR boundary shifts leading to NRY expansion over time.

Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

1970 ◽  
Vol 28 ◽  
pp. 456-457
Author(s):  
L. E. Murr ◽  
G. Wong
Keyword(s):  
Single Crystal ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
High Rate ◽  
Flash Evaporation ◽  
Optimum Load ◽  
Single Crystal Films ◽  
Crystal Films ◽  
A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

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