Different patterns of X chromosome inactivity in lymphocytes and fibroblasts of a human balanced X; autosome translocation

1982 ◽  
Vol 60 (2) ◽  
pp. 126-129 ◽  
Author(s):  
Bernard Hellkuhl ◽  
Albert de la Chapelle ◽  
Karl-Heinz Grzeschik
Keyword(s):  
X Chromosome ◽  
Autosome Translocation

Genetic activity at the albino locus in Cattanach's insertion in the mouse

Development ◽  
1986 ◽  
Vol 96 (1) ◽  
pp. 295-302
Author(s):  
M. S. Deol ◽  
Gillian M. Truslove ◽  
Anne McLaren
Keyword(s):  
X Chromosome ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
The Other ◽  
Normal Allele ◽  
Cell Type ◽  
Direct Examination ◽  
Autosome Translocation ◽  
Genetic Activity ◽  
Preferential Inactivation

Cattanach's insertion (Is(In7;X)1Ct or XCt) includes the normal allele at the albino locus (c+), which is subject to inactivation of the X chromosome carrying it, so that XCtX; c c mice have albino and pigmented patches. The X-autosome translocation T(X;16)16H or XT16H leads to preferential inactivation of the other X chromosome in female cells, so that XCtXT16H; c c mice are almost entirely white. However, they grow darker with age, as if reversal of inactivation of the c+ allele were taking place in increasing numbers of melanocytes. To test whether this is dependent only on age or whether it is related to the number of times the animal has moulted, hair was repeatedly plucked from selected areas at the early telogen stage when the follicles are also removed, assuming that the melanocytes or melanoblasts in that region of the skin would be forced to undergo further divisions to colonize the new follicles. The plucked areas grew darker at the same rate as the rest of the coat, suggesting that the progressive reversal of inactivation is dependent only on age. As direct examination of melanocytes in the follicles is difficult, they were examined in the choroid and the retinal pigment epithelium (RPE) of the eye. The frequency of the pigmented cells was lower in the choroid than in the RPE. Since the melanocytes in these structures are different in origin as well as in physical characteristics, it appears that cell type influences either reversal of inactivation, or the frequency with which the influence of the X chromosome extends to the albino locus.

scholarly journals The location of Cattanach's translocation in the X-chromosome linkage map of the mouse

1966 ◽  
Vol 8 (2) ◽  
pp. 253-256 ◽  
Author(s):  
B. M. Cattanach
Keyword(s):  
Linkage Group ◽  
Linkage Map ◽  
X Chromosome ◽  
Present Communication ◽  
Group I ◽  
Autosome Translocation

In Cattanach's X-autosome translocation a piece of autosome of linkage group I has been inserted into the X-chromosome and a piece of X may have been reciprocally translocated to the autosome (Cattanach, 1961; Ohno & Cattanach, 1962). The present communication reports investigations to locate the autosomal insertion in the X-chromosome linkage map and provide evidence pertinent to the question of the possible reciprocal nature of the rearrangement; a brief summary of the results has already been reported (Cattanach & Isaacson, 1965).

scholarly journals CYTOLOGICAL IDENTIFICATION OF THE CHROMOSOMES INVOLVED IN SEARLE'S TRANSLOCATION AND THE LOCATION OF THE CENTROMERE IN THE X CHROMOSOME OF THE MOUSE

Genetics ◽  
1972 ◽  
Vol 71 (4) ◽  
pp. 643-648
Author(s):  
Eva M Eicher ◽  
Muriel N Nesbitt ◽  
Uta Francke
Keyword(s):  
Linkage Group ◽  
X Chromosome ◽  
Chromosome 16 ◽  
Autosome Translocation ◽  
Group Xv

ABSTRACT The autosome in Searle's X-autosome translocation has been shown to be chromosome 16. The breakpoint in chromosome 16 is slightly proximal to the middle and in the X is slightly distal to the middle.—Available evidence indicates that either Linkage Group XV or Linkage Group XIX is carried on chromosome 16.—The centromere of the X chromosome is at the spf end of the linkage group.

Non-random X-chromosome inactivation in mouse X-autosome translocation embryos—location of the inactivation centre

Development ◽  
1983 ◽  
Vol 78 (1) ◽  
pp. 1-22
Author(s):  
Sohaila Rastan
Keyword(s):  
Simple Model ◽  
X Chromosome ◽  
X Chromosome Inactivation ◽  
Chromosome Inactivation ◽  
Differential Staining ◽  
Female Embryo ◽  
Reciprocal Translocations ◽  
Inactive X Chromosome ◽  
Autosome Translocation ◽  
Chromosome Material

X-chromosome inactivation was investigated cytologically using the modified Kanda method which differentially stains inactive X-chromosome material at metaphase in balanced 13½-day female embryos heterozygous for four X-autosome rearrangements, reciprocal translocations T(X;4)37H, T(X;11)38H and T(X;16)16H (Searle's translocation) and the insertion translocation Is(7;X)1Ct (Cattanach's translocation). In all cases non-random inactivation was found. In the reciprocal translocation heterozygotes only one translocation product ever showed Kanda staining. In addition in a proportion of cells from T(X;4)37H, T(X;11)38H and Is(7;X)1Ct the Kanda staining revealed differential staining of X-chromosome material and attached autosomal material within the translocation product. In a study of 8½-day female embryos doubly heterozygous for Searle's translocation and Cattanach's translocation two unbalanced types of embryo were found. In one type of unbalanced female embryo of the karyotype 40(X(7)/X16;16/16) no inactivated X-chromosomal material is found. A second unbalanced type of female embryo, of the presumptive karyotype 40(X(7)/XN;16x/l6) was found in which two inactivated chromosomes were present in the majority of metaphase spreads. A simple model for the initiation of X-chromosome inactivation based on the presence of a single inactivation centre distal to the breakpoint in Searle's translocation explains these findings.

P–554 Reproductive risks and preimplantation genetic testing intervention for X-autosome translocation carriers

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Y Shimin ◽  
C Dehua ◽  
L Keli ◽  
L Xiurong ◽  
H Liang ◽  
...  
Keyword(s):  
Genetic Testing ◽  
X Chromosome ◽  
X Inactivation ◽  
Healthy Children ◽  
Next Generation ◽  
Preimplantation Genetic Testing ◽  
Congenital Cardiac Anomaly ◽  
Autosome Translocation ◽  
Translocation Breakpoints ◽  
Congenital Disabilities

Abstract Study question For X-autosome translocation [t(X-A)] carriers, is it a more applicable preimplantation genetic testing (PGT) strategy, that distinguishing noncarrier from euploid/ balanced embryos and prioritized transfer? Summary answer Noncarrier and carrier embryos discrimination in PGT is an applicable strategy to avoid transferring genetic and reproductive risks to the offspring of t(X-A) carriers. What is known already Balanced t(X-A) is a specific reciprocal translocation, with a higher risk of detrimental phenotype and fertility issues compared to individuals with autosomal translocation. Alternative X-chromosome inactivation (XCI) is a specific pathogenic mechanism in this population. For carrier offspring of couples with t(X-A), the genetic counseling is challenged in both the prenatal and postpartum stages, because of the complexity and severity of phenotype outcomes that are unpredictable and associated with the complex XCI mechanism. Therefore, caution is necessary when designing a PGT strategy for couples with t(X-A). Study design, size, duration A retrospective study. We collected a 3-year-old girl with maternal translocation 46,X,t(X;1)(q28;p31.1) presenting with multiple congenital disabilities. Three couples with female t(X-A) carrier requesting for PGT. Participants/materials, setting, methods Karyotype analysis, whole-exome sequencing (WES), and X inactivation analysis were performed for the girl with congenital cardiac anomaly, language defect, and mild neurodevelopmental delay. PGT based on next-generation sequencing following the microdissecting junction region to distinguish noncarrier and carrier embryos were used in three couples with female t(X-A) carrier (Cases 1–3). Main results and the role of chance The girl carried a maternal balanced translocation 46,X,t(X;1)(q28;p31.1). WES revealed none monogenic mutation related to her phenotype, but she carried a rare skewed inactivation of the translocation X chromosome and spread to the adjacent interstitial 1p segment, contrary to her mother. All translocation breakpoints of Cases 1–3 were successfully identified and each couple underwent one PGT cycle. Thirty oocytes were retrieved, and 13 blastocysts were eligible for biopsy, of which 6 (46.15%) embryos were balanced and only 4 were noncarriers. Three frozen embryo transfers with noncarrier embryos resulted in the birth of two healthy children (one girl and one boy), who were subsequently confirmed to have normal karyotypes. We reported a girl with multiple congenital disabilities resulting from maternally balanced t(X-A) and validated that noncarrier and carrier embryo discrimination is an effective and applicable strategy for avoiding transferring genetic and reproductive risks to the offspring from t(X-A) carriers. Limitations, reasons for caution Here, we reported a girl with multiple congenital disabilities resulting from maternally balanced t(X-A) found different XCI patterns, while we did not further determine the mechanism causing the different XCI patterns between the girl and her mother. Wider implications of the findings: We demonstrated passing on a balanced t(X-A) may result in clinical manifestations associated with the X-inactivation, and verified the PGT strategy, that distinguishing normal and carrier embryos in can widely applied in t(X-A) carrier couples to avoid the genetic and reproductive risk of transferring t(X-A) to the next generation. Trial registration number the National Key Research & Developmental Program of China (2018YFC1004900), the National Natural Science Foundation of China (81771645 and 81971447), the Key Grant of Prevention and Treatment of Birth Defect from Hunan Province (2019SK1012), Hunan Provincial Grant for Innovative Province Construction (2019SK4012) and the Research Grant of CITIC-Xiangya (YNXM–201916).

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 X-autosome and X-Y translocations in female carriers: X-chromosome inactivation easily detectable by 5-ethynyl-2-deoxyuridine (EdU)

2017 ◽  
Vol 20 (1) ◽  
pp. 87-90 ◽  
Author(s):  
M Donat ◽  
A Louis ◽  
K Kreskowski ◽  
M Ziegler ◽  
A Weise ◽  
...  
Keyword(s):  
X Chromosome ◽  
Chromosome Translocation ◽  
X Chromosome Inactivation ◽  
Chromosome Inactivation ◽  
Correct Interpretation ◽  
Cell Level ◽  
Diagnostic Use ◽  
Autosome Translocation ◽  
Skewed X Chromosome Inactivation ◽  
Female Carriers

Abstract Here we report one new case each of an X-autosome translocation (maternally derived), and an X-Y-chromosome translocation. Besides characterizing the involved breakpoints and/or imbalances in detail by molecular cyto-genetics, also skewed X-chromosome inactivation was determined on single cell level using 5-ethynyl-2-deoxyuridine (EdU). Thus, we confirmed that the recently suggested EdU approach can be simply adapted for routine diagnostic use. The latter is important, as only by knowing the real pattern of the skewed X-chromosome inactivation, correct interpretation of obtained results and subsequent reliable genetic counseling, can be done.

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.

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