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.

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.

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.

The Continuum of Psychosis and Its Genetic Origins

1990 ◽  
Vol 156 (6) ◽  
pp. 788-797 ◽  
Author(s):  
T. J. Crow
Keyword(s):  
Sex Chromosome ◽  
Homo Sapiens ◽  
Polymorphic Marker ◽  
Cerebral Dominance ◽  
Homo Erectus ◽  
Evolutionary Development ◽  
Pseudoautosomal Region ◽  
Sibling Pairs ◽  
Homo Habilis ◽  
Y Chromosomes

Attempts to draw a line of genetic demarcation between schizophrenic and affective illnesses have failed. It must be assumed that these diseases are genetically related. A post-mortem study has demonstrated that enlargement of the temporal horn of the lateral ventricle in schizophrenia but not in Alzheimer-type dementia is selective to the left side of the brain. This suggests that the gene for psychosis is the ‘cerebral dominance gene‘, the factor that determines the asymmetrical development of the human brain. That the psychosis gene is located in the pseudoautosomal region of the sex chromosomes is consistent with observations that sibling pairs with schizophrenia are more often than would be expected of the same sex and share alleles of a polymorphic marker at the short-arm telomeres of the X and Y chromosomes above chance expectation. That the cerebral dominance gene also is pseudoautosomal is suggested by the pattern of verbal and performance deficits associated with sex-chromosome aneuploidies. The psychoses may thus represent aberrations of a late evolutionary development underlying the recent and rapid increase in brain weight in the transition fromAustralopithecusthroughHomo habilisandHomo erectustoHomo sapiens.

Polymorphism and differentiation of rainbow trout Y chromosomes

Genome ◽  
2004 ◽  
Vol 47 (6) ◽  
pp. 1105-1113 ◽  
Author(s):  
Alicia Felip ◽  
Atushi Fujiwara ◽  
William P Young ◽  
Paul A Wheeler ◽  
Marc Noakes ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Y Chromosome ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Morphological Differentiation ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Y Chromosomes ◽  
Cytogenetic Analyses ◽  
Clonal Lines ◽  
Sex Locus

Most fish species show little morphological differentiation in the sex chromosomes. We have coupled molecular and cytogenetic analyses to characterize the male-determining region of the rainbow trout (Oncorhynchus mykiss) Y chromosome. Four genetically diverse male clonal lines of this species were used for genetic and physical mapping of regions in the vicinity of the sex locus. Five markers were genetically mapped to the Y chromosome in these male lines, indicating that the sex locus was located on the same linkage group in each of the lines. We also confirmed the presence of a Y chromosome morphological polymorphism among these lines, with the Y chromosomes from two of the lines having the more common heteromorphic Y chromosome and two of the lines having Y chromosomes morphologically similar to the X chromosome. The fluorescence in situ hybridization (FISH) pattern of two probes linked to sex suggested that the sex locus is physically located on the long arm of the Y chromosome. Fishes appear to be an excellent group of organisms for studying sex chromosome evolution and differentiation in vertebrates because they show considerable variability in the mechanisms and (or) patterns involved in sex determination.Key words: sex chromosomes, sex markers, cytogenetics, rainbow trout, fish.

Molecular Cytogenetic Analysis of Karyotype and Y Chromosome Conservation in Species of the Genus Talpa (Insectivora)

2020 ◽  
Vol 160 (5) ◽  
pp. 264-271
Author(s):  
Juana Gutierrez ◽  
Gael Aleix-Mata ◽  
Juan A. Marchal ◽  
María Arroyo ◽  
Riccardo Castiglia ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Y Chromosome ◽  
Repetitive Dna ◽  
Dna Sequences ◽  
Chromosome Painting ◽  
Chromosomal Mapping ◽  
Repeated Dna ◽  
Molecular Cytogenetic ◽  
Y Chromosomes ◽  
Cytogenetic Analyses

The Talpidae family has a highly stable karyotype. Most of the chromosome studies in this mammal group, however, employed classical cytogenetic techniques. Molecular cytogenetic analyses are still scarce and, for example, no repeated DNA sequences have been described to date. In this work, we used sequence analysis, chromosomal mapping of a LINE1 retroelement sequence, as well as chromosome painting with a whole Y chromosome probe of T. occidentalis to compare the karyotypes of 3 species of the genus Talpa (T. occidentalis, T. romana, and T. aquitania). Our results demonstrate that in Talpa genomes LINE1 sequences are widely distributed on all chromosomes but are enriched in pericentromeric C-band-positive regions. In addition, these LINE1 accumulate on the Y chromosomes of the 3 Talpa species regardless of their euchromatic or heterochromatic condition. Chromosome painting shows that the Y chromosomes in these 3 species are highly conserved. Interestingly, they share sequences with heterochromatic blocks on chromosome pairs 14 and 16 and, to a lesser degree, with the pericentromeric regions of other autosomes. Together, our analyses demonstrate that the repetitive DNA content of chromosomes from Talpa species is highly conserved.

scholarly journals Sex ratio distortion in bovine sperm correlates to recombination in the pseudoautosomal region

2000 ◽  
Vol 75 (1) ◽  
pp. 53-59 ◽  
Author(s):  
JOANNA SZYDA ◽  
HENNER SIMIANER ◽  
SIGBJØRN LIEN
Keyword(s):  
Sex Ratio ◽  
Recombination Rate ◽  
Regression Models ◽  
Segregation Ratio ◽  
Pseudoautosomal Region ◽  
Logistic Regression Models ◽  
Bovine Sperm ◽  
Y Chromosomes ◽  
Ratio Distortion ◽  
Sex Ratio Distortion

A total of 2122 single sperm from 35 bulls belonging to six different paternal half-sib groups were analysed with respect to two markers in the bovine pseudoautosomal region (PAR) and sex- specific loci on the X and Y chromosomes, respectively. A segregation ratio significantly different from 1[ratio ]1 was observed in a test over all families, with a higher proportion of X-bearing gametes (53·5%). The analysis of recombination conducted separately for X- and Y-bearing sperm showed that X-bearing sperm cells possess highly significant individual and between-family variability in recombination rate, whereas Y-bearing sperm show linkage homogeneity. To test whether the two phenomena are related, different logistic regression models were fitted to the data. The results show that sex ratio significantly correlates with changes in recombination rate among X-bearing but not among Y-bearing sperm. Different hypotheses to explain these observations are discussed.

scholarly journals Pseudoautosomal gene SHOX exhibits sex-biased random monoallelic expression and contributes to sex difference in height

2021 ◽  
Author(s):  
Atsushi Hattori ◽  
Atsuhito Seki ◽  
Naoto Inaba ◽  
Kazuhiko Nakabayashi ◽  
Kazue Takeda ◽  
...  
Keyword(s):  
Sex Difference ◽  
Sex Chromosome ◽  
Phenotypic Diversity ◽  
Pseudoautosomal Region ◽  
Monoallelic Expression ◽  
Adult Women ◽  
Adult Men ◽  
Y Chromosomes ◽  
Male Specific ◽  
Novel Model

AbstractAdult men are, on average, ∼13 cm taller than adult women. Although previous studies have suggested a significant contribution of sex chromosomal genes to sexual dimorphism in height, all attempts to identify a male-specific growth gene have failed. In the present study, we analyzed transcripts from cartilage tissues, and found that the expression of SHOX, a growth-promoting gene in the pseudoautosomal region on the X and Y chromosomes, was lower in females than in males. DNA methylation analyses showed that SHOX has some characteristics of genes subjected to X chromosome inactivation (XCI). These findings indicate that sex difference in human height is mainly ascribed to incomplete spreading of XCI on a pseudoautosomal gene. More importantly, RT-PCR of fibroblast clones revealed XCI-independent random clonal monoallelic expression of SHOX. We presume that during eutherian evolution, SHOX translocated from an autosome to the proto-sex chromosome without losing the epigenetic memory of random clonal monoallelic expression and subsequently underwent partial XCI. This study provides a novel model of epigenetic gene regulation leading to phenotypic diversity in humans.

scholarly journals New Insights into Mammalian Sex Chromosome Structure and Evolution from High-quality Bovine X and Y Chromosome Sequences

2019 ◽  
Author(s):  
Ruijie Liu ◽  
Wai Yee Low ◽  
Rick Tearle ◽  
Sergey Koren ◽  
Jay Ghurye ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Immune Modulation ◽  
Sex Chromosome ◽  
Inflammatory Responses ◽  
Structure Evolution ◽  
Pseudoautosomal Region ◽  
Evolutionary Divergence ◽  
High Quality ◽  
Global Regulators ◽  
Y Chromosomes

Abstract Background Mammalian X chromosomes are mainly euchromatic with a similar size and structure among species whereas Y chromosomes are smaller, have undergone substantial evolutionary changes and accumulated male specific genes and genes involved in sex determination. The PAR is conserved on the X and Y and pair during meiosis. The structure, evolution and function of mammalian sex chromosomes is still poorly understood because few species have high quality sex chromosome assemblies. Results Here we report the first bovine sex chromosome assemblies that include the complete pseudoautosomal region (PAR) spanning 6.84 Mb and three Y chromosome X-degenerate (X-d) regions. We show that the ruminant PAR comprises 31 genes and is similar to the PAR of pig and dog but extends further than those of human and horse. Differences in the pseudoautosomal boundaries are consistent with evolutionary divergence times. Conclusions A bovidae-specific expansion of members of the lipocalin gene family in the PAR may reflect immune-modulation and anti-inflammatory responses that contribute to parasite resistance in ruminants. Comparison of the X-d regions of Y chromosomes across species reveal five conserved X-Y gametologs, which are global regulators of gene activity, and may have a fundamental role in mammalian sexual dimorphism.

scholarly journals Evolutionary dynamics of the human pseudoautosomal regions

PLoS Genetics ◽  
2021 ◽  
Vol 17 (4) ◽  
pp. e1009532
Author(s):  
Bruno Monteiro ◽  
Miguel Arenas ◽  
Maria João Prata ◽  
António Amorim
Keyword(s):  
Genetic Diversity ◽  
Evolutionary Dynamics ◽  
Male Meiosis ◽  
Normal Male ◽  
Male Recombination ◽  
Evolutionary Forces ◽  
Evolutionary Origins ◽  
Y Chromosomes ◽  
Pseudoautosomal Regions ◽  
Transmission Studies

Recombination between the X and Y human sex chromosomes is limited to the two pseudoautosomal regions (PARs) that present quite distinct evolutionary origins. Despite the crucial importance for male meiosis, genetic diversity patterns and evolutionary dynamics of these regions are poorly understood. In the present study, we analyzed and compared the genetic diversity of the PAR regions using publicly available genomic sequences encompassing both PAR1 and PAR2. Comparisons were performed through allele diversities, linkage disequilibrium status and recombination frequencies within and between X and Y chromosomes. In agreement with previous studies, we confirmed the role of PAR1 as a male-specific recombination hotspot, but also observed similar characteristic patterns of diversity in both regions although male recombination occurs at PAR2 to a much lower extent (at least one recombination event at PAR1 and in ≈1% in normal male meioses at PAR2). Furthermore, we demonstrate that both PARs harbor significantly different allele frequencies between X and Y chromosomes, which could support that recombination is not sufficient to homogenize the pseudoautosomal gene pool or is counterbalanced by other evolutionary forces. Nevertheless, the observed patterns of diversity are not entirely explainable by sexually antagonistic selection. A better understanding of such processes requires new data from intergenerational transmission studies of PARs, which would be decisive on the elucidation of PARs evolution and their role in male-driven heterosomal aneuploidies.

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