scholarly journals How did the guppy Y chromosome evolve?

PLoS Genetics ◽  
2021 ◽  
Vol 17 (8) ◽  
pp. e1009704
Author(s):  
Deborah Charlesworth ◽  
Roberta Bergero ◽  
Chay Graham ◽  
Jim Gardner ◽  
Karen Keegan
Keyword(s):  
Natural Selection ◽  
Y Chromosome ◽  
X Chromosome ◽  
Sex Chromosome ◽  
Genetic Recombination ◽  
The Other ◽  
Y Chromosomes ◽  
Suppressed Recombination ◽  
Close Relatives ◽  
Male Coloration

The sex chromosome pairs of many species do not undergo genetic recombination, unlike the autosomes. It has been proposed that the suppressed recombination results from natural selection favouring close linkage between sex-determining genes and mutations on this chromosome with advantages in one sex, but disadvantages in the other (these are called sexually antagonistic mutations). No example of such selection leading to suppressed recombination has been described, but populations of the guppy display sexually antagonistic mutations (affecting male coloration), and would be expected to evolve suppressed recombination. In extant close relatives of the guppy, the Y chromosomes have suppressed recombination, and have lost all the genes present on the X (this is called genetic degeneration). However, the guppy Y occasionally recombines with its X, despite carrying sexually antagonistic mutations. We describe evidence that a new Y evolved recently in the guppy, from an X chromosome like that in these relatives, replacing the old, degenerated Y, and explaining why the guppy pair still recombine. The male coloration factors probably arose after the new Y evolved, and have already evolved expression that is confined to males, a different way to avoid the conflict between the sexes.

scholarly journals Memoirs: Marsupial Spermatogenesis

1923 ◽  
Vol s2-67 (266) ◽  
pp. 203-218
Author(s):  
A. W. GREENWOOD
Keyword(s):  
Y Chromosome ◽  
X Chromosome ◽  
Meiotic Division ◽  
Sex Chromosome ◽  
The Other ◽  
Pachytene Stage ◽  
Late Pachytene ◽  
Early Pachytene ◽  
Y Chromosomes ◽  
And Function

In the three animals studied the total number of chromosomes in the male is as follows : Phascolarctus 16 (14 autosomes + XY). Sarcophilus 14 (12 autosomes + XY). Dasyurus 14 (12 autosomes + XY). In the female the number of chromosomes is as follows : Phascolarctus 16 (14 autosomes + XX). Sarcophilus 14 (12 autosomes + XX). In all animals dealt with in this paper the Y-chromosome is very minute in size compared with the other chromosomes; also the X-chromosome is much smaller than any of the autosomes. Chromomeres are conspicuous during syndesis, early pachytene, and early diplotene stages. The early pachytene stage is followed by a late pachytene stage in which the threads become diffuse and lose their capacity for taking up the stain. Except in the early meiotic prophase the sex chromosome remains compact and deeply stained and does not thread out like the autosomes. In all the above animals the first meiotic division is reductional, separating the X- and the Y-chromosomes, and the second division is equational, in each cell the sex chromosome dividing. The spermatozoa are therefore of two kinds, one containing an X-chromosome and the other containing a Y-chromosome. No further reduction in the number of chromosomes takes place during the second meiotic division. The Y-chromosome could not be identified during the meiotic phase until the metaphase of the first meiotic division. At this stage in Phascolarctus the sex chromosomes are separate and do not form a bivalent. The archoplasm seems to exert some influence on the chromatin threads at synizesis and during the early pachytene stage. In the former case the contraction takes place to that side of the nucleus at which the archoplasmic mass is situated; in the latter the chromosomes are in the form of thick loops with the ends of the chromosomes pointing towards the archoplasmic mass. In Phascolarctus the Sertoli cells are very large and possess peculiar rod-like bodies, the origin and function of which was not arrived at. The result of experiments seem to show that the rods are not affected by the action of digestive fluids.

scholarly journals Extreme heterogeneity in sex chromosome differentiation and dosage compensation in livebearers

2019 ◽  
Vol 116 (38) ◽  
pp. 19031-19036 ◽  
Author(s):  
Iulia Darolti ◽  
Alison E. Wright ◽  
Benjamin A. Sandkam ◽  
Jake Morris ◽  
Natasha I. Bloch ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Dosage Compensation ◽  
Sex Chromosomes ◽  
Poecilia Reticulata ◽  
Sex Chromosome ◽  
Sequencing Data ◽  
Chromosome Differentiation ◽  
Y Chromosomes ◽  
Shared Ancestry ◽  
Suppressed Recombination

Once recombination is halted between the X and Y chromosomes, sex chromosomes begin to differentiate and transition to heteromorphism. While there is a remarkable variation across clades in the degree of sex chromosome divergence, far less is known about the variation in sex chromosome differentiation within clades. Here, we combined whole-genome and transcriptome sequencing data to characterize the structure and conservation of sex chromosome systems across Poeciliidae, the livebearing clade that includes guppies. We found that the Poecilia reticulata XY system is much older than previously thought, being shared not only with its sister species, Poecilia wingei, but also with Poecilia picta, which diverged roughly 20 million years ago. Despite the shared ancestry, we uncovered an extreme heterogeneity across these species in the proportion of the sex chromosome with suppressed recombination, and the degree of Y chromosome decay. The sex chromosomes in P. reticulata and P. wingei are largely homomorphic, with recombination in the former persisting over a substantial fraction. However, the sex chromosomes in P. picta are completely nonrecombining and strikingly heteromorphic. Remarkably, the profound degradation of the ancestral Y chromosome in P. picta is counterbalanced by the evolution of functional chromosome-wide dosage compensation in this species, which has not been previously observed in teleost fish. Our results offer important insight into the initial stages of sex chromosome evolution and dosage compensation.

Mapping the mouse X chromosome: possible symmetry in the location of a family of sequences on the mouse X and Y chromosomes

Development ◽  
1987 ◽  
Vol 101 (Supplement) ◽  
pp. 107-116
Author(s):  
Philip Avner ◽  
Colin Bishop ◽  
Laurence Amar ◽  
Jacques Cambrou ◽  
Didier Hatat ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Y Chromosome ◽  
X Chromosome ◽  
Somatic Cell Hybrid ◽  
The Other ◽  
Interspecific Crosses ◽  
Somatic Cell Hybrid Panel ◽  
Mus Spretus ◽  
Y Chromosomes

Major advances in our knowledge of the genetic organization of the mouse X chromosome have been obtained by the use of interspecific crosses involving Mus spretus-derived strains. This system has been used to study sequences detected by three probes 80Y/B, 302Y/B and 371Y/B isolated from a mouse Y-chromosome library which have been shown to recognize both male–female common and male–female differential sequences. These patterns are due to the presence of a family of cross-reacting sequences on the mouse X and Y chromosomes. Detailed genetic analysis of the localization of the X-chromosomespecific sequences using both a somatic cell hybrid panel and an interspecific mouse cross has revealed the presence of at least three discrete clusters of loci (X–Y)A, (X–Y)B and (X–Y)C. Two of these clusters, (X–Y)B and (X–Y)C, lie distally on the mouse X chromosome, the other cluster (X–Y)A being situated close to the centromere. In situ hybridization shows a striking symmetry in the localization of the major sequences on both the X and Y chromosomes detected by these probes, hybridization being preferentially localized to a subcentromeric and subtelomeric region on each chromosome. This striking localization symmetry between the X and Y chromosome sequences is discussed in terms of the extensive pairing of the X–Y chromosomes noted during meiosis.

scholarly journals Effects of Human Sex Chromosome Dosage on Spatial Chromosome Organization

2018 ◽  
Author(s):  
Ziad Jowhar ◽  
Sigal Shachar ◽  
Prabhakar R. Gudla ◽  
Darawalee Wangsa ◽  
Erin Torres ◽  
...  
Keyword(s):  
Y Chromosome ◽  
X Chromosome ◽  
Genome Organization ◽  
Sex Chromosome ◽  
Chromatin Condensation ◽  
Chromosome Territory ◽  
Chromosome Organization ◽  
Genetic Syndromes ◽  
Y Chromosomes ◽  
And Function

AbstractSex chromosome aneuploidies (SCAs) are common genetic syndromes characterized by the presence of an aberrant number of X and Y chromosomes due to meiotic defects. These conditions impact structure and function of diverse tissues, but the proximal effects of SCA on genome organization are unknown. Here, to determine the consequences of SCAs on global genome organization, we have analyzed multiple architectural features of chromosome organization in a comprehensive set of primary cells from SCA patients with various ratios of X and Y chromosomes by use of imaging-based high-throughput Chromosome Territory Mapping (HiCTMap). We find that X chromosome supernumeracy does not affect the size, volume or nuclear position of the Y chromosome or an autosomal chromosome. In contrast, the active X chromosome undergoes architectural changes as a function of increasing X copy number, as measured by a decrease in size and an increase in circularity, which is indicative of chromatin compaction. With Y chromosome supernumeracy, Y chromosome size is reduced suggesting higher chromatin condensation. The radial positioning of chromosomes is unaffected in SCA karyotypes. Taken together, these observations document changes in genome architecture in response to alterations in sex chromosome numbers and point to trans-effects of dosage compensation on chromosome organization.

scholarly journals Effects of human sex chromosome dosage on spatial chromosome organization

2018 ◽  
Vol 29 (20) ◽  
pp. 2458-2469 ◽  
Author(s):  
Ziad Jowhar ◽  
Sigal Shachar ◽  
Prabhakar R. Gudla ◽  
Darawalee Wangsa ◽  
Erin Torres ◽  
...  
Keyword(s):  
Y Chromosome ◽  
X Chromosome ◽  
Genome Organization ◽  
Sex Chromosome ◽  
Chromatin Condensation ◽  
Chromosome Territory ◽  
Chromosome Organization ◽  
Genetic Syndromes ◽  
Y Chromosomes ◽  
And Function

Sex chromosome aneuploidies (SCAs) are common genetic syndromes characterized by the presence of an aberrant number of X and Y chromosomes due to meiotic defects. These conditions impact the structure and function of diverse tissues, but the proximal effects of SCAs on genome organization are unknown. Here, to determine the consequences of SCAs on global genome organization, we have analyzed multiple architectural features of chromosome organization in a comprehensive set of primary cells from SCA patients with various ratios of X and Y chromosomes by use of imaging-based high-throughput chromosome territory mapping (HiCTMap). We find that X chromosome supernumeracy does not affect the size, volume, or nuclear position of the Y chromosome or an autosomal chromosome. In contrast, the active X chromosome undergoes architectural changes as a function of increasing X copy number as measured by a decrease in size and an increase in circularity, which is indicative of chromatin compaction. In Y chromosome supernumeracy, Y chromosome size is reduced suggesting higher chromatin condensation. The radial positioning of chromosomes is unaffected in SCA karyotypes. Taken together, these observations document changes in genome architecture in response to alterations in sex chromosome numbers and point to trans-effects of dosage compensation on chromosome organization.

scholarly journals Spot Urine for Sex Determination Forensic Identifications with Amelogenin Locus and Y chromosomes (DYS 19). Bercak Urin untuk Identifikasi Forensik Jenis Kelamin dengan Lokus Amelogenin dan Y Kromosom (DYS19)

2018 ◽  
Vol 20 (3) ◽  
pp. 180
Author(s):  
Yeti Eka Sispita Sari
Keyword(s):  
Sex Determination ◽  
Y Chromosome ◽  
X Chromosome ◽  
Sex Chromosome ◽  
Dna Amplification ◽  
Single Copy ◽  
Amelogenin Gene ◽  
Spot Urine ◽  
Y Chromosomes ◽  
Two Samples

AbstractBackground:  Amelogenin gene was a single copy gene located in an X chromosome and a Y chromosome. The location of amelogenin gene for identification of sex chromosome has good variability between the form and the shape of the X chromosome and the Y chromosome and between Amelogenin alleles among different populations. Purpose: To prove urine spot examination on the results of the sex determination through Deoxyribo Nucleid Acid (DNA) isolation using amelogenin and Y chromosome loci (DYS19). Methods: Spotting the microscopic examination of urine samples to determine the presence or absence of urethral epithelial cells, followed by isolation Deoxyribo nucleid Acid (DNA) in order to determine the extent and purity of DNA amplification. Then performed Polymerase Chain Reaction (PCR) amelogenin locus at 106bp - 112bp and Y chromosomes (DYS19) at 232 -268 bp. Results: in 9 samples of men from 3 families with 3 kinship of different regions shows the results of different tests, because Amel Y variation between individual and populations method of determining the sex of 100% was inaccurate. In some men Amel Y can be removed entirely. This research should be visualized one band on the Y chromosome (DYS19) and the Amelogenin two bands during electrophoresis occurs misidentification of the sample as a woman. Conclusions: Identification of sex using Amelogenin locus and Y chromosomes (DYS19) has six identical and ambiguous results because the two samples shown as the sign of men but visualized as women, another sample was not visualized because of the thick level and concentration of Deoxyribo nucleid Acid (DNA).Keywords: Urine Spot, Sex Determination, Amelogenin, Y chromosome (DYS19).

scholarly journals Telomere-to-telomere assembly of a fish Y chromosome reveals the origin of a young sex chromosome pair

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Lingzhan Xue ◽  
Yu Gao ◽  
Meiying Wu ◽  
Tian Tian ◽  
Haiping Fan ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Sex Chromosomes ◽  
Chromosome Pair ◽  
Sex Chromosome ◽  
Structural Variations ◽  
Recombination Suppression ◽  
Chromosome Differentiation ◽  
Y Chromosomes ◽  
Recent Origin ◽  
Mastacembelus Armatus

Abstract Background The origin of sex chromosomes requires the establishment of recombination suppression between the proto-sex chromosomes. In many fish species, the sex chromosome pair is homomorphic with a recent origin, providing species for studying how and why recombination suppression evolved in the initial stages of sex chromosome differentiation, but this requires accurate sequence assembly of the X and Y (or Z and W) chromosomes, which may be difficult if they are recently diverged. Results Here we produce a haplotype-resolved genome assembly of zig-zag eel (Mastacembelus armatus), an aquaculture fish, at the chromosomal scale. The diploid assembly is nearly gap-free, and in most chromosomes, we resolve the centromeric and subtelomeric heterochromatic sequences. In particular, the Y chromosome, including its highly repetitive short arm, has zero gaps. Using resequencing data, we identify a ~7 Mb fully sex-linked region (SLR), spanning the sex chromosome centromere and almost entirely embedded in the pericentromeric heterochromatin. The SLRs on the X and Y chromosomes are almost identical in sequence and gene content, but both are repetitive and heterochromatic, consistent with zero or low recombination. We further identify an HMG-domain containing gene HMGN6 in the SLR as a candidate sex-determining gene that is expressed at the onset of testis development. Conclusions Our study supports the idea that preexisting regions of low recombination, such as pericentromeric regions, can give rise to SLR in the absence of structural variations between the proto-sex chromosomes.

Fire-Setting Behavior in Individuals With Klinefelter Syndrome

PEDIATRICS ◽  
1988 ◽  
Vol 82 (1) ◽  
pp. 115-117
Author(s):  
MARVIN E. MILLER ◽  
STEPHEN SULKES
Keyword(s):  
Criminal Behavior ◽  
Sex Chromosome ◽  
Klinefelter Syndrome ◽  
Mental Deficiency ◽  
The Other ◽  
Sexual Deviation ◽  
Reactive Depression ◽  
Y Chromosomes ◽  
Psychiatric Problems ◽  
Chromosome Disorder

Klinefelter syndrome is a sex chromosome disorder with an incidence of approximately two per 1,000 male newborns.1 Eighty percent of individuals with Klinefelter syndrome are 47,XXY, whereas the other 20% have a variant sex chromosomal constitution with additional supernumerary X or Y chromosomes (ie, 48,XXXY, 48XXYY) or are mosaic.2 Individuals with Klinefelter syndrome have small testes which usually cannot produce sperm or normal amounts of testosterone. The results of this are infertility and undermasculinization. Behavioral and psychiatric problems are also common in individuals with Klinefelter syndrome and include personality disorder, reactive depression, schizophrenia, mental deficiency, sexual deviation, criminal behavior, and alcoholism.3

scholarly journals The evolution of the Y chromosome with X-Y recombination.

Genetics ◽  
1988 ◽  
Vol 119 (3) ◽  
pp. 711-720
Author(s):  
A G Clark
Keyword(s):  
Natural Selection ◽  
Y Chromosome ◽  
Meiotic Recombination ◽  
Population Genetic ◽  
Sex Chromosome ◽  
Genetic Model ◽  
Chromosome Polymorphism ◽  
Significant Finding ◽  
Special Cases ◽  
Theoretical Population

Abstract A theoretical population genetic model is developed to explore the consequences of X-Y recombination in the evolution of sex chromosome polymorphism. The model incorporates one sex-determining locus and one locus subject to natural selection. Both loci have two alleles, and the rate of classical meiotic recombination between the loci is r. The alleles at the sex-determining locus specify whether the chromosome is X or Y, and the alleles at the selected locus are arbitrarily labeled A and a. Natural selection is modeled as a process of differential viabilities. The system can be expressed in terms of three recurrence equations, one for the frequency of A on the X-bearing gametes produced by females, one for each of the frequency of A on the X- and Y-bearing gametes produced by males. Several special cases are examined, including X chromosome dominance and symmetric selection. Unusual equilibria are found with the two sexes having very different allele frequencies at the selected locus. A significant finding is that the allowance of recombination results in a much greater opportunity for polymorphism of the Y chromosome. Tighter linkage results in a greater likelihood for equilibria with a large difference between the sex chromosomes in allele frequency.

scholarly journals A second X chromosome contributes to resilience in a mouse model of Alzheimer’s disease

2020 ◽  
Vol 12 (558) ◽  
pp. eaaz5677 ◽  
Author(s):  
Emily J. Davis ◽  
Lauren Broestl ◽  
Samira Abdulai-Saiku ◽  
Kurtresha Worden ◽  
Luke W. Bonham ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Y Chromosome ◽  
X Chromosome ◽  
Sex Chromosome ◽  
Testicular Development ◽  
X Chromosomes ◽  
Model Of Alzheimer’S Disease ◽  
Preclinical Ad ◽  
Brain Expression

A major sex difference in Alzheimer’s disease (AD) is that men with the disease die earlier than do women. In aging and preclinical AD, men also show more cognitive deficits. Here, we show that the X chromosome affects AD-related vulnerability in mice expressing the human amyloid precursor protein (hAPP), a model of AD. XY-hAPP mice genetically modified to develop testicles or ovaries showed worse mortality and deficits than did XX-hAPP mice with either gonad, indicating a sex chromosome effect. To dissect whether the absence of a second X chromosome or the presence of a Y chromosome conferred a disadvantage on male mice, we varied sex chromosome dosage. With or without a Y chromosome, hAPP mice with one X chromosome showed worse mortality and deficits than did those with two X chromosomes. Thus, adding a second X chromosome conferred resilience to XY males and XO females. In addition, the Y chromosome, its sex-determining region Y gene (Sry), or testicular development modified mortality in hAPP mice with one X chromosome such that XY males with testicles survived longer than did XY or XO females with ovaries. Furthermore, a second X chromosome conferred resilience potentially through the candidate gene Kdm6a, which does not undergo X-linked inactivation. In humans, genetic variation in KDM6A was linked to higher brain expression and associated with less cognitive decline in aging and preclinical AD, suggesting its relevance to human brain health. Our study suggests a potential role for sex chromosomes in modulating disease vulnerability related to AD.

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