Correlation between sexual phenotype and X-chromosome inactivation pattern in the X*XY wood lemming

Schempp, Werner; Wiberg, Ulf H.; Fredga, Karl

doi:10.1159/000132099

Cited by 16 publications

(7 citation statements)

References 6 publications

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“…Winking et al (1981) suggested that the variable phenotypic expression was a consequence of non-random inactivation of X and X*, with the two types either in unequal proportion or unequally distributed. Support for the non-random inactivation hypothesis was received from studies of the replication patterns of the X chromosomes in fibroblast cultures initiated from one X* XY male and one X* XY female (Schempp et al 1985). The normal X was late-replicating (i.e.…”

Section: Why Is the Wood Lemming Such A Good Model For Studies In Sex Determination ?mentioning

confidence: 99%

Aberrant chromosomal sex-determining mechanisms in mammals, with special reference to species with XY females

Fredga

1988

Phil. Trans. R. Soc. Lond. B

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Both mouse and man have the common XX/XY sex chromosome mechanism. The X chromosome is of original size (5-6% of female haploid set) and the Y is one of the smallest chromosomes of the complement. But there are species, belonging to a variety of orders, with composite sex chromosomes and multiple sex chromosome systems: XX/XY1Y2 and X1X1X2X2/X1X2Y. The original X or the Y, respectively, have been translocated on to an autosome. The sex chromosomes of these species segregate regularly at meiosis; two kinds of sperm and one kind of egg are produced and the sex ratio is the normal 1:1. Individuals with deviating sex chromosome constitutions (XXY, XYY, XO or XXX) have been found in at least 16 mammalian species other than man. The phenotypic manifestations of these deviating constitutions are briefly discussed. In the dog, pig, goat and mouse exceptional XX males and in the horse XY females attract attention. Certain rodents have complicated mechanisms for sex determination: Ellobius lutescens and Tokudaia osimensis have XO males and females. Both sexes of Microtus oregoni are gonosomic mosaics (male OY/XY, female XX/XO). The wood lemming, Myopus schisticolor, the collared lemming, Dirostonyx torquatus, and perhaps also one or two species of the genus Akodon have XX and XY females and XY males. The XX, X*X and X*Y females of Myopus and Dicrostonyx are discussed in some detail. The wood lemming has proved to be a favourable natural model for studies in sex determination, because a large variety of sex chromosome aneuploids are born relatively frequently. The dosage model for sex determination is not supported by the wood lemming data. For male development, genes on both the X and the Y chromosomes are necessary.

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Section: Why Is the Wood Lemming Such A Good Model For Studies In Sex Determination ?mentioning

confidence: 99%

Aberrant chromosomal sex-determining mechanisms in mammals, with special reference to species with XY females

Fredga

1988

Phil. Trans. R. Soc. Lond. B

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“…XX, XX*, and X*Y, due to the presence of a third sex chromosome, named X*, that carries a feminizing mutation that prevents the initiation of the male sex-determining program in X*Y individuals. Although limited investigation seemed to suggest random X inactivation of either the X or X* in XX* females (H. Winking, personal communication, in Schempp et al (1985)), other results showed more striking patterns, with complete nonrandom X or X* inactivation (100%) in specimens with numerically aberrant X*XY sex chromosome constitution (Schempp et al 1985). Recently, a novel case of unusual mammalian sex determination system was described in the African pygmy mouse, Mus minutoides, a close relative of the house mouse (Veyrunes et al 2010;Rahmoun et al 2014;Zhao et al 2017).…”

Section: Introductionmentioning

confidence: 99%

X inactivation in a mammal species with three sex chromosomes

Veyrunes¹,

Pérez²

2017

Chromosoma

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X inactivation is a fundamental mechanism in eutherian mammals to restore a balance of X-linked gene products between XY males and XX females. However, it has never been extensively studied in a eutherian species with a sex determination system that deviates from the ubiquitous XX/XY. In this study, we explore the X inactivation process in the African pygmy mouse Mus minutoides, that harbours a polygenic sex determination with three sex chromosomes: Y, X, and a feminizing mutant X, named X*; females can thus be XX, XX*, or X*Y, and all males are XY. Using immunofluorescence, we investigated histone modification patterns between the two X chromosome types. We found that the X and X* chromosomes are randomly inactivated in XX* females, while no histone modifications were detected in X*Y females. Furthermore, in M. minutoides, X and X* chromosomes are fused to different autosomes, and we were able to show that the X inactivation never spreads into the autosomal segments. Evaluation of X inactivation by immunofluorescence is an excellent quantitative procedure, but it is only applicable when there is a structural difference between the two chromosomes that allows them to be distinguished.

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“…Although these types of variations suggest that chromosome rearrangements can play a major role in speciation, they also present a conundrum for biologists: apparently similar types of rearrangements in humans, laboratory mice, and other mammalian species often result in sterility, especially in the carrier males (for review see de Boer and de Jong, 1989;Speed, 1989). Questions about "unusual" mammalian sex chromosomes have been a major theme of Karl Fredga's career, whether the abnormality can be attributed to a gonosome (sex) chromosome-autosome rearrangement (Fredga, 1965) or large blocks of heterochromatin (Ashley et al, 1989;Schempp et al, 1985). His interest has ranged from the molecular effects of "unusual" sex chromosomes on sex determination (Liu et al, 2001) and X inactivation (Schempp et al, 1985), to cytological effects on meiosis (Akhverdyan and Fredga, 2001;Ashley et al, 1989), to the "macro" effects on populations (Fredga and Jaarola, 1997), up to and including the "super-macro" effects on speciation and evolution (Bilton et al, 1998).…”

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confidence: 99%

X-Autosome translocations, meiotic synapsis, chromosome evolution and speciation

Ashley

2002

Cytogenet Genome Res

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Several theories have been proposed to explain the often-noted sterility of both reciprocal and Robertsonian X-autosome translocations in male mammals. However, there are a number of species in which all members of the species carry a Robertsonian X-autosome translocation. Meiosis in spermatocytes from these sterile vs. fertile animals is compared within the context of these theories. New technologies and insights into underlying mechanisms are summarized and suggestions presented for further studies.

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Correlation between sexual phenotype and X-chromosome inactivation pattern in the X*XY wood lemming

Cited by 16 publications

References 6 publications

Aberrant chromosomal sex-determining mechanisms in mammals, with special reference to species with XY females

Aberrant chromosomal sex-determining mechanisms in mammals, with special reference to species with XY females

X inactivation in a mammal species with three sex chromosomes

X-Autosome translocations, meiotic synapsis, chromosome evolution and speciation

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