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 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.

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.

Concordance by Sex in Sibling Pairs with Schizophrenia is Paternally Inherited

1989 ◽  
Vol 155 (1) ◽  
pp. 92-97 ◽  
Author(s):  
Timothy J. Crow ◽  
Lynn E. DeLisi ◽  
Eve C. Johnstone
Keyword(s):  
Sex Chromosomes ◽  
Sibling Pair ◽  
Pseudoautosomal Region ◽  
Same Sex ◽  
Sibling Pairs ◽  
History Of ◽  
Parent Of Origin ◽  
The Difference ◽  
Maternal Side

The hypothesis that the gene for schizophrenia is located in the pseudoautosomal region of the sex chromosomes predicts that same-sex concordance will occur in paternally rather than maternally derived pairs. In 120 families that included at least one sibling pair with schizophrenia, affected members were significantly more likely to be of the same sex when there was a history of illness on the paternal than on the maternal side, the difference remaining significant when parent of origin was assessed by three different methods. The finding is as predicted by the pseudoautosomal hypothesis: therefore a search for the gene should be focused on this small (three megabase) region of the genome. The ratio of same to mixed sex pairs in paternally-derived cases (approximately 3:1) suggests the gene is located in the centromeric one-third of the pseudoautosomal region.

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

scholarly journals Sex chromosome pairing mediated by euchromatic homology in Drosophila male meiosis

2019 ◽  
Author(s):  
Christopher A. Hylton ◽  
Katie Hansen ◽  
Andrew Bourgeois ◽  
John E. Tomkiel
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Intergenic Spacer ◽  
Male Meiosis ◽  
Early Prophase ◽  
Dna Breaks ◽  
Late Prophase ◽  
Prophase I ◽  
Y Chromosomes ◽  
Meiosis I

ABSTRACTTo maintain proper ploidy, haploid sex cells must undergo two subsequent meiotic divisions. During meiosis I, homologs pair and remain conjoined until segregation at anaphase. Drosophila melanogaster spermatocytes are unique in that the canonical events of meiosis I including synaptonemal complex (SC) formation, double-strand DNA breaks, and chiasmata are absent. Sex chromosomes pair at intergenic spacer sequences within the heterochromatic rDNA while euchromatin is required to pair and segregate autosomal homologies, suggesting that pairing may be limited to specific sequences. However, previous work generated from genetic segregation assays or observations of late prophase I/prometaphase I chromosome associations fail to differentiate pairing from conjunction. Here, we separately examined the capability of X euchromatin to pair and conjoin using an rDNA-deficient X and a series of Dp(1;Y) chromosomes. Genetic assays showed that duplicated X euchromatin can substitute for endogenous rDNA pairing sites. Segregation was not proportional to homology length, and pairing could be mapped to nonoverlapping sequences within a single Dp(1;Y). Using fluorescent in situ hybridization (FISH) to early prophase I spermatocytes, we showed that pairing occurred with high fidelity at all homologies tested. Pairing was unaffected by the presence of X rDNA, nor could it be explained by rDNA magnification. By comparing genetic and cytological data, we determined that centromere proximal pairings were best at segregation. Segregation was dependent on the conjunction protein Stromalin in Meiosis while the autosomal-specific Teflon was dispensable. Overall, our results suggest that pairing may occur at all homologies, but there may be sequence or positional requirements for conjunction.ARTICLE SUMMARYDrosophila males have evolved a unique system of chromosome segregation in meiosis that lacks recombination. Chromosomes pair at selected sequences suggesting that early steps of meiosis may also differ in this organism. Using Y chromosomes carrying portions of X material, we show that pairing between sex chromosomes can be mediated by sequences other than the previously identified rDNA pairing sites. We propose that pairing may simply be homology-based and may not differ from canonical meiosis observed in females. The main difference in males may be that conjunctive mechanisms that join homologs in the absence of crossovers.

Two permanent linear chains of sex chromosomes in Neotermes fulvescens and karyotypes of two other neotropical Kalotermitidae species (Insecta, Isoptera)

Genome ◽  
1995 ◽  
Vol 38 (5) ◽  
pp. 958-967 ◽  
Author(s):  
Vanderlei Geraldo Martins ◽  
Alejo Mesa
Keyword(s):  
Sex Chromosomes ◽  
Diploid Number ◽  
Linear Chain ◽  
Neotropical Region ◽  
Male Meiosis ◽  
The Other ◽  
South American ◽  
Y Chromosomes ◽  
Linear Chains ◽  
Males And Females

Meiosis and (or) mitosis of males and females of Cryptotermes brevis, Eucryptotermes wheeleri, and Neotermes fulvescens, all of them from the neotropical region, were analyzed. Cryptotermes brevis showed a similar karyotype to that obtained by other authors for specimens of the neartic and Australian regions (2n = 36 for females and 2n = 37 for males, with XX and XYY sex mechanisms, respectively). Eucryptotermes wheeleri, the only species that has been described in this genus, showed the lowest number of chromosomes reported for Isoptera (2n = 22) until now. The male meiosis of this species presents a linear chain of six sex chromosomes, three of them being X and three of them Y chromosomes. Neotermes fulvescens showed a diploid number of 40 for males and 42 for females and, in the first male meiosis, two linear chains of chromosomes, both related to sex. One of the chains, named A, presented nine chromosomes and the other, named B, seven chromosomes. Hypotheses to explain these mechanisms are formulated in this paper and putative ancestral relationships with other species of Kalotermitidae are presented.Key words: termite, Neotermes, two linear chains, translocations, South American.

Cytogenetics of the Herbert River ringtail possum, Pseudocheirus herbertensis (Diprotodonta: Pseudocheiridae): evidence for two species

Genome ◽  
1989 ◽  
Vol 32 (6) ◽  
pp. 1119-1123
Author(s):  
J. D. Murray ◽  
G. M. McKay ◽  
J. W. Winter ◽  
S. Ingleby
Keyword(s):  
Sex Chromosomes ◽  
Chromosome Numbers ◽  
Sex Chromosome ◽  
Centric Fusion ◽  
Male Meiosis ◽  
Y Chromosomes ◽  
Ringtail Possum

The two Herbert River ringtail possum subspecies, Pseudocheirus herbertensis ssp. herbertensis and P. h. ssp. cinereus, have diploid chromosome numbers of 12 and 16, respectively. The sex chromosomes of both subspecies are exceptionally large, with the X and Y chromosomes being approximately 16 and 12% of the haploid autosomal complement, respectively. A sex chromosome bivalent cannot be identified during male meiosis and a sex vesicle is not present during pachytene. The two karyotypes are most likely related by two centric fusion events affecting the autosomal complement. We conclude that the X and Y chromosomes have been translocated onto homologous autosomes to give t(XA) t(YA) ♀ t(XA) t(XA) ♂. Our data also strongly support the separation of P. h. cinereus as a distinct species.Key words: karyotypes, sex chromosomes, speciation.

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.

scholarly journals Epigenetic Dysregulation of Mammalian Male Meiosis Caused by Interference of Recombination and Synapsis

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2311
Author(s):  
Roberto de la Fuente ◽  
Florencia Pratto ◽  
Abrahan Hernández-Hernández ◽  
Marcia Manterola ◽  
Pablo López-Jiménez ◽  
...  
Keyword(s):  
Transcriptional Regulation ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Male Meiosis ◽  
Epigenetic Marks ◽  
Prophase I ◽  
Recombination Proteins ◽  
Meiotic Sex Chromosome Inactivation ◽  
Y Chromosomes ◽  
Genes Encoding

Meiosis involves a series of specific chromosome events, namely homologous synapsis, recombination, and segregation. Disruption of either recombination or synapsis in mammals results in the interruption of meiosis progression during the first meiotic prophase. This is usually accompanied by a defective transcriptional inactivation of the X and Y chromosomes, which triggers a meiosis breakdown in many mutant models. However, epigenetic changes and transcriptional regulation are also expected to affect autosomes. In this work, we studied the dynamics of epigenetic markers related to chromatin silencing, transcriptional regulation, and meiotic sex chromosome inactivation throughout meiosis in knockout mice for genes encoding for recombination proteins SPO11, DMC1, HOP2 and MLH1, and the synaptonemal complex proteins SYCP1 and SYCP3. These models are defective in recombination and/or synapsis and promote apoptosis at different stages of progression. Our results indicate that impairment of recombination and synapsis alter the dynamics and localization pattern of epigenetic marks, as well as the transcriptional regulation of both autosomes and sex chromosomes throughout prophase-I progression. We also observed that the morphological progression of spermatocytes throughout meiosis and the dynamics of epigenetic marks are processes that can be desynchronized upon synapsis or recombination alteration. Moreover, we detected an overlap of early and late epigenetic signatures in most mutants, indicating that the normal epigenetic transitions are disrupted. This can alter the transcriptional shift that occurs in spermatocytes in mid prophase-I and suggest that the epigenetic regulation of sex chromosomes, but also of autosomes, is an important factor in the impairment of meiosis progression in mammals.

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.

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