scholarly journals Recombination between the X and Y chromosomes and the Sxr region of the mouse

1992 ◽  
Vol 60 (3) ◽  
pp. 175-184 ◽  
Author(s):  
Anne McLaren ◽  
Elizabeth Simpson ◽  
Colin E. Bishop ◽  
Michael J. Mitchell ◽  
Susan M. Darling
Keyword(s):  
Y Chromosome ◽  
X Chromosome ◽  
Recombination Frequency ◽  
Male Meiosis ◽  
Homologous Region ◽  
Crossing Over ◽  
Female Meiosis ◽  
Unequal Crossing Over ◽  
Y Chromosomes ◽  
Autosome Translocation

SummaryThe Sxr (sex-reversed) region that carries a copy of the mouse Y chromosomal testis-determining gene can be attached to the distal end of either the Y or the X chromosome. During male meiosis, Sxr recombined freely between the X and Y chromosomes, with an estimated recombination frequency not significantly different from 50% in either direction. During female meiosis, Sxr recombined freely between the X chromosome to which it was attached and an X-autosome translocation. A male mouse carrying the original Sxra region on its Y chromosome, and the shorter Sxrb variant on the X, also showed 50% recombination between the sex chromosomes. Evidence of unequal crossing-over between the two Sxr regions was obtained: using five markers deleted from Sxrb, 3 variant Sxr regions were detected in 159 progeny (1·9%). Four other variants (one from the original cross and three from later generations) were presumed to have been derived from illegitimate pairing and crossing-over between Sxrb and the homologous region on the short arm of the Y chromosome. The generation of new variants throws light on the arrangement of gene loci and other markers within the short arm of the mouse Y chromosome.

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.

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.

Mapping the Y chromosome

Development ◽  
1987 ◽  
Vol 101 (Supplement) ◽  
pp. 39-39
Author(s):  
P. N. Goodfellow
Keyword(s):  
Sex Determination ◽  
Y Chromosome ◽  
X Chromosome ◽  
Dna Probes ◽  
Genetic Maps ◽  
Variable Amount ◽  
Regional Localization ◽  
Y Chromosomes ◽  
Xx Males ◽  
Human Y Chromosome

DNA probes isolated from the human Y chromosome have been used to resolve two fundamental problems concerning the biology of sex determination in man. Coincidentally, resolution of these problems has generated genetic maps of the short arm of the human Y chromosome and has allowed the regional localization of TDF. The first problem to be solved was the origin of XX males (de la Chapelle, this symposium): the majority of XX males are caused by a telomeric exchange between the X and Y chromosomes that results in TDF and a variable amount of Y-derived material being transferred to the X chromosome. The differing amounts of Y-derived material present in XX males has been used as the basis of a ‘deletion’ map of the Y chromosome (Müller; Ferguson-Smith & Affara; this symposium).

Structure, organization, and sequence of alpha satellite DNA from human chromosome 17: evidence for evolution by unequal crossing-over and an ancestral pentamer repeat shared with the human X chromosome

1986 ◽  
Vol 6 (9) ◽  
pp. 3156-3165
Author(s):  
J S Waye ◽  
H F Willard
Keyword(s):  
Human Chromosome ◽  
X Chromosome ◽  
Repeat Unit ◽  
Higher Order ◽  
Chromosome 17 ◽  
Crossing Over ◽  
Human Chromosomes ◽  
Alpha Satellite ◽  
Unequal Crossing Over ◽  
Human Chromosome 17

The centromeric regions of all human chromosomes are characterized by distinct subsets of a diverse tandemly repeated DNA family, alpha satellite. On human chromosome 17, the predominant form of alpha satellite is a 2.7-kilobase-pair higher-order repeat unit consisting of 16 alphoid monomers. We present the complete nucleotide sequence of the 16-monomer repeat, which is present in 500 to 1,000 copies per chromosome 17, as well as that of a less abundant 15-monomer repeat, also from chromosome 17. These repeat units were approximately 98% identical in sequence, differing by the exclusion of precisely 1 monomer from the 15-monomer repeat. Homologous unequal crossing-over is suggested as a probable mechanism by which the different repeat lengths on chromosome 17 were generated, and the putative site of such a recombination event is identified. The monomer organization of the chromosome 17 higher-order repeat unit is based, in part, on tandemly repeated pentamers. A similar pentameric suborganization has been previously demonstrated for alpha satellite of the human X chromosome. Despite the organizational similarities, substantial sequence divergence distinguishes these subsets. Hybridization experiments indicate that the chromosome 17 and X subsets are more similar to each other than to the subsets found on several other human chromosomes. We suggest that the chromosome 17 and X alpha satellite subsets may be related components of a larger alphoid subfamily which have evolved from a common ancestral repeat into the contemporary chromosome-specific subsets.

The Jumping SHOX Gene—Crossover in the Pseudoautosomal Region Resulting in Unusual Inheritance of Leri-Weill Dyschondrosteosis

2011 ◽  
Vol 96 (2) ◽  
pp. E356-E359 ◽  
Author(s):  
Sarina G. Kant ◽  
Hetty J. van der Kamp ◽  
Marjolein Kriek ◽  
Egbert Bakker ◽  
Boudewijn Bakker ◽  
...  
Keyword(s):  
Genetic Counseling ◽  
Y Chromosome ◽  
X Chromosome ◽  
Sex Chromosome ◽  
Recombination Frequency ◽  
Pseudoautosomal Region ◽  
Shox Gene ◽  
Mesomelic Dysplasia ◽  
Very High ◽  
Meiosis I

abstract Context: During meiosis I, the recombination frequency in the pseudoautosomal region on Xp and Yp (PAR1) in males is very high. As a result, mutated genes located within the PAR1 region can be transferred from the Y-chromosome to the X-chromosome and vice versa. Patients: Here we describe three families with SHOX abnormalities resulting in Leri-Weill dyschondrosteosis or Langer mesomelic dysplasia. Results: In about half of the segregations investigated, a transfer of the SHOX abnormality to the alternate sex chromosome was demonstrated. Conclusions: Patients with an abnormality of the SHOX gene should receive genetic counseling as to the likelihood that they may transmit the mutation or deletion to a son as well as to a daughter.

Observations on chromosomal male sterility in Drosophila melanogaster

1984 ◽  
Vol 26 (1) ◽  
pp. 67-77
Author(s):  
James. C. Stone
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Functional Unit ◽  
Primary Spermatocyte ◽  
Male Meiosis ◽  
Centromeric Heterochromatin ◽  
Control Element ◽  
Male Sterile ◽  
Cis Acting ◽  
Autosome Translocation

Observations on a variety of metazoans have shown that the X chromosome becomes functionally inactive earlier in male meiosis than the remainder of the genome. Genetic analyses of male-sterile chromosome rearrangements in Drosophila suggest that the X chromosome in this species behaves as a distinct functional unit, and have further suggested that X-chromosome expression is regulated in the primary spermatocyte by a cis-acting control element located in the centromeric heterochromatin. Attempts to test the X-inactivation hypothesis of chromosomal sterility in Drosophila and attempts to map the hypothetical control element are described here. Cytological observations on a male-sterile X-autosome translocation are also discussed.

scholarly journals Silencing of Unpaired Chromatin and Histone H2A Ubiquitination in Mammalian Meiosis

2005 ◽  
Vol 25 (3) ◽  
pp. 1041-1053 ◽  
Author(s):  
Willy M. Baarends ◽  
Evelyne Wassenaar ◽  
Roald van der Laan ◽  
Jos Hoogerbrugge ◽  
Esther Sleddens-Linkels ◽  
...  
Keyword(s):  
Mouse Models ◽  
Meiotic Prophase ◽  
Transcriptional Silencing ◽  
Male Meiosis ◽  
Histone H2a ◽  
Barr Body ◽  
Female Meiosis ◽  
Autosomal Region ◽  
Y Chromosomes ◽  
The Relationship

ABSTRACT During meiotic prophase in male mammals, the X and Y chromosomes are incorporated in the XY body. This heterochromatic body is transcriptionally silenced and marked by increased ubiquitination of histone H2A. This led us to investigate the relationship between histone H2A ubiquitination and chromatin silencing in more detail. First, we found that ubiquitinated H2A also marks the silenced X chromosome of the Barr body in female somatic cells. Next, we studied a possible relationship between H2A ubiquitination, chromatin silencing, and unpaired chromatin in meiotic prophase. The mouse models used carry an unpaired autosomal region in male meiosis or unpaired X and Y chromosomes in female meiosis. We show that ubiquitinated histone H2A is associated with transcriptional silencing of large chromatin regions. This silencing in mammalian meiotic prophase cells concerns unpaired chromatin regions and resembles a phenomenon described for the fungus Neurospora crassa and named meiotic silencing by unpaired DNA.

Using Ancestry-Informative SNPs to Quantify Introgression of European Alleles into North American Red Foxes

2019 ◽  
Vol 110 (7) ◽  
pp. 782-792 ◽  
Author(s):  
Yi Hung Kuo ◽  
Stevi L Vanderzwan ◽  
Adrienne E Kasprowicz ◽  
Benjamin N Sacks
Keyword(s):  
United States ◽  
Y Chromosome ◽  
X Chromosome ◽  
Atlantic Coastal Plain ◽  
European Ancestry ◽  
Eastern United States ◽  
Red Foxes ◽  
Mt Dna ◽  
Chromosome Markers ◽  
Y Chromosomes

Abstract A recent study demonstrated that British red foxes introduced to the mid-Atlantic coastal plain (ACP) of the eastern United States during the late 18th century successfully interbred with indigenous American red foxes despite half a million year’s divergence. However, a large disparity in frequency of European mitochondria (27%) versus Y chromosomes (1%) left unclear the magnitude of genetic exchange. We sought to quantify genomic introgression using 35 autosomal and 5 X-chromosome ancestry-informative markers (AIMs) in conjunction with diagnostic Y chromosome single nucleotide polymorphism (Y-SNP) markers to characterize the modern state of red foxes in the eastern United States and to gain insight into the potential role of reproductive barriers. European admixture was highest in the ACP and apparently restricted to the central eastern United States. We estimated only slightly (and nonsignificantly) European ancestry in autosomal than X-chromosome markers. European ancestry from autosomal and X-chromosome markers (36.4%) was higher than the corresponding mitochondrial (mt) DNA estimate (26.4%) in the ACP. Only 1 of 124 males (<1%) in the ACP had European Y chromosomes, which was similar to the neighboring regions, in which 2 of 99 (2%) males carried a European Y chromosome (the same haplotype). Although we could not rule out drift as the cause of low European Y-chromosome frequency, results were also consistent with F1 male infertility. In the future, more extensive genomic sequencing will enable a more thorough investigation of possible barrier genes on the X chromosome as well as throughout the genome.

scholarly journals Identification of heterosomes in spermatoza of rams with 54,XX/54,XY chimerism

2008 ◽  
Vol 53 (No. 5) ◽  
pp. 250-254 ◽  
Author(s):  
A. Kozubska-Sobocinska ◽  
B. Rejduch
Keyword(s):  
Sex Ratio ◽  
Y Chromosome ◽  
X Chromosome ◽  
Fluorescent Signal ◽  
Fish Technique ◽  
Y Chromosomes

The aim of the study was to identify heterosomes in the semen of three Romanov rams – carriers of leukocyte chimerism (FISH technique) and to determine the proportions between spermatozoa with X and Y chromosomes. The choice of bovine probes for hybridization with ram heterosomes was dictated by genetic conservatism of bovine and ovine heterosomes. The ratio between spermatozoa with a yellow fluorescent signal containing the X chromosome in the haploid set and spermatozoa with a red-purple signal indicating the presence of the Y chromosome, taking into account spermatozoa with no signal, was 52%:43%:5% in ram No. PL100006077676; 47%:44%:9% in ram No. PL100006078031; and 48%:46%:6% in ram No. PL100006078895. The results obtained lead us to conclude that the 54,XX/54,XY chimerism has no effect on sex ratio in offspring.

scholarly journals Structure, organization, and sequence of alpha satellite DNA from human chromosome 17: evidence for evolution by unequal crossing-over and an ancestral pentamer repeat shared with the human X chromosome.

1986 ◽  
Vol 6 (9) ◽  
pp. 3156-3165 ◽  
Author(s):  
J S Waye ◽  
H F Willard
Keyword(s):  
Human Chromosome ◽  
X Chromosome ◽  
Repeat Unit ◽  
Higher Order ◽  
Chromosome 17 ◽  
Crossing Over ◽  
Human Chromosomes ◽  
Alpha Satellite ◽  
Unequal Crossing Over ◽  
Human Chromosome 17

The centromeric regions of all human chromosomes are characterized by distinct subsets of a diverse tandemly repeated DNA family, alpha satellite. On human chromosome 17, the predominant form of alpha satellite is a 2.7-kilobase-pair higher-order repeat unit consisting of 16 alphoid monomers. We present the complete nucleotide sequence of the 16-monomer repeat, which is present in 500 to 1,000 copies per chromosome 17, as well as that of a less abundant 15-monomer repeat, also from chromosome 17. These repeat units were approximately 98% identical in sequence, differing by the exclusion of precisely 1 monomer from the 15-monomer repeat. Homologous unequal crossing-over is suggested as a probable mechanism by which the different repeat lengths on chromosome 17 were generated, and the putative site of such a recombination event is identified. The monomer organization of the chromosome 17 higher-order repeat unit is based, in part, on tandemly repeated pentamers. A similar pentameric suborganization has been previously demonstrated for alpha satellite of the human X chromosome. Despite the organizational similarities, substantial sequence divergence distinguishes these subsets. Hybridization experiments indicate that the chromosome 17 and X subsets are more similar to each other than to the subsets found on several other human chromosomes. We suggest that the chromosome 17 and X alpha satellite subsets may be related components of a larger alphoid subfamily which have evolved from a common ancestral repeat into the contemporary chromosome-specific subsets.

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