X-4 Translocations and Meiotic Drive in Drosophila melanogaster Males: Role of Sex Chromosome Pairing

Genetics ◽  
1987 ◽  
Vol 116 (3) ◽  
pp. 409-413
Author(s):  
Bruce McKee
Keyword(s):  
Drosophila Melanogaster ◽  
Y Chromosome ◽  
X Chromosome ◽  
Chromosome Pairing ◽  
Sex Chromosome ◽  
Meiotic Drive ◽  
Meiotic Pairing ◽  
Size Dependent ◽  
Chromosome Breakpoint

ABSTRACT Males carrying certain X-4 translocations exhibit strongly skewed sperm recovery ratios. The XP4D half of the translocation disjoins regularly from the Y chromosome and the 4PXD half disjoins regularly from the normal 4. Yet the smaller member of each bivalent is recovered in excess of its pairing partner, apparently due to differential gametic lethality. Chromosome recovery probabilities are multiplicative; the viability of each genotype is the product of the recovery probability of its component chromosomes. Meiotic drive can also be caused by deficiency for X heterochromatin. In(1)sc4Lsc8R males show the same size dependent chromosome recoveries and multiplicative recovery probabilities found in T(1;4)BS males. Meiotic drive in In(1)sc4Lsc8R males has been shown to be due to X-Y pairing failure. Although pairing is regular in the T(X;4) males, the striking phenotypic parallels suggest a common explanation. The experiments described below show that the two phenomena are, in fact, one and the same. X-4 translocations are shown to have the same effect on recovery of independently assorting chromosomes as does In(1)sc4Lsc8R. Addition of pairing sites to the 4PXD half of the translocation eliminates drive. A common explanation—failure of the distal euchromatic portion of the X chromosome to participate in X:Y meiotic pairing—is suggested as the cause for drive. The effect of X chromosome breakpoint on X-4 translocation induced meiotic drive is investigated. It is found that translocations with breakpoints distal to 13C on the salivary map do not cause drive while translocations broken proximal to 13C cause drive. The level of drive is related to the position of the breakpoint—the more proximal the breakpoint the greater the drive.

Male Sterility and Meiotic Drive Associated With Sex Chromosome Rearrangements in Drosophila: Role of X-Y Pairing

Genetics ◽  
1998 ◽  
Vol 149 (1) ◽  
pp. 143-155 ◽  
Author(s):  
Bruce D McKee ◽  
Kathy Wilhelm ◽  
Cynthia Merrill ◽  
Xiao-jia Ren
Keyword(s):  
Male Sterility ◽  
Sex Chromosome ◽  
Meiotic Drive ◽  
Repeated Sequence ◽  
Meiotic Pairing ◽  
Intergenic Spacers ◽  
Male Specific ◽  
The Relationship ◽  
Novel Model

Abstract In Drosophila melanogaster, deletions of the pericentromeric X heterochromatin cause X-Y nondisjunction, reduced male fertility and distorted sperm recovery ratios (meiotic drive) in combination with a normal Y chromosome and interact with Y-autosome translocations (T(Y;A)) to cause complete male sterility. The pericentromeric heterochromatin has been shown to contain the male-specific X-Y meiotic pairing sites, which consist mostly of a 240-bp repeated sequence in the intergenic spacers (IGS) of the rDNA repeats. The experiments in this paper address the relationship between X-Y pairing failure and the meiotic drive and sterility effects of Xh deletions. X-linked insertions either of complete rDNA repeats or of rDNA fragments that contain the IGS were found to suppress X-Y nondisjunction and meiotic drive in Xh−/Y males, and to restore fertility to Xh−/T(Y;A) males for eight of nine tested Y-autosome translocations. rDNA fragments devoid of IGS repeats proved incapable of suppressing either meiotic drive or chromosomal sterility. These results indicate that the various spermatogenic disruptions associated with X heterochromatic deletions are all consequences of X-Y pairing failure. We interpret these findings in terms of a novel model in which misalignment of chromosomes triggers a checkpoint that acts by disabling the spermatids that derive from affected spermatocytes.

scholarly journals DoesStellateCause Meiotic Drive inDrosophila melanogaster?

Genetics ◽  
2002 ◽  
Vol 161 (4) ◽  
pp. 1551-1559 ◽  
Author(s):  
Massimo Belloni ◽  
Patrizia Tritto ◽  
Maria Pia Bozzetti ◽  
Gioacchino Palumbo ◽  
Leonard G Robbins
Keyword(s):  
Drosophila Melanogaster ◽  
Y Chromosome ◽  
X Chromosome ◽  
Evolutionary History ◽  
Active Element ◽  
Meiotic Drive

AbstractDrosophila melanogaster males deficient for the crystal (cry) locus of the Y chromosome that carry between 15 and 60 copies of the X-linked Stellate (Ste) gene are semisterile, have elevated levels of nondisjunction, produce distorted sperm genotype ratios (meiotic drive), and evince hyperactive transcription of Ste in the testes. Ste seems to be the active element in this system, and it has been proposed that the ancestral Ste gene was “selfish” and increased in frequency because it caused meiotic drive. This hypothetical evolutionary history is based on the idea that Ste overexpression, and not the lack of cry, causes the meiotic drive of cry– males. To test whether this is true, we have constructed a Ste-deleted X chromosome and examined the phenotype of Ste–/cry– males. If hyperactivity of Ste were necessary for the transmission defects seen in cry– males, cry– males completely deficient for Ste would be normal. Although it is impossible to construct a completely Ste– genotype, we find that Ste–/cry– males have exactly the same phenotype as Ste+/cry– males. The deletion of all X chromosome Ste copies not only does not eliminate meiotic drive and nondisjunction, but it also does not even reduce them below the levels produced when the X carries 15 copies of Ste.

scholarly journals The effect of novel chromosome position and variable dose on the genetic behavior of the Responder (Rsp) element of the Segregation distorter (SD) system of Drosophila melanogaster.

Genetics ◽  
1989 ◽  
Vol 121 (4) ◽  
pp. 751-763 ◽  
Author(s):  
T W Lyttle
Keyword(s):  
Drosophila Melanogaster ◽  
Y Chromosome ◽  
Meiotic Drive ◽  
Meiotic Pairing ◽  
Genetic Element ◽  
Chromosome Position ◽  
Segregation Distorter ◽  
Sensitive Allele ◽  
Sperm Dysfunction ◽  
Variable Dose

Abstract In the Segregation distorter (SD) system of meiotic drive, a minimum of two trans-acting elements [Sd and E(SD)] act in concert to cause a certain probability of dysfunction for sperm carrying a sensitive allele at the Responder (Rsp) target locus. By employing a number of insertional translocations of autosomal material into the long arm of the Y chromosome, Rsp can be mapped as the most proximal locus in the 2R heterochromatin as defined both by cytology and lethal complementation tests. Several of these insertional translocations result in the transposition of Rsp to the Y chromosome, where its sensitivity remains virtually unaltered. This argues that Rsp is separable from the second chromosome centromere, that its behavior does not depend on its gross chromosomal position, and that meiotic pairing of the chromosomes carrying the various SD elements is not a prerequisite for sperm dysfunction. Several other translocations apparently leave both resulting chromosomes at least partially sensitive to SD action, suggesting that Rsp is a large subdivisible genetic element. This view is compatible with observations published elsewhere that suggest that Rsp is a cytologically large region of highly repetitive AT-rich DNA. The availability of Y-linked copies of Rsp also allows the construction of SD males carrying two independently segregating Rsp alleles; this in turn allows the production of sperm with zero, one or two Rsp copies from the same male. Examination of the relative recovery proportions of progeny arising from these gametes suggests that sperm with two Rsp copies survive at much lower frequencies than would be predicted if each Rsp acted independently in causing sperm dysfunction. Possible explanations for such behavior are discussed.

scholarly journals Chromosomal Position Effects Reveal Different cis-Acting Requirements for rDNA Transcription and Sex Chromosome Pairing in Drosophila melanogaster

Genetics ◽  
2000 ◽  
Vol 155 (3) ◽  
pp. 1195-1211 ◽  
Author(s):  
Albert Briscoe ◽  
John E Tomkiel
Keyword(s):  
Drosophila Melanogaster ◽  
Chromosome Pairing ◽  
Sex Chromosome ◽  
Position Effect ◽  
Meiotic Pairing ◽  
Rdna Transcription ◽  
Position Effects ◽  
Cis Acting ◽  
Chromosomal Position ◽  
Rdna Loci

Abstract In Drosophila melanogaster, the rDNA loci function in ribosome biogenesis and nucleolar formation and also as sex chromosome pairing sites in male meiosis. These activities are not dependent on the heterochromatic location of the rDNA, because euchromatic transgenes are competent to form nucleoli and restore pairing to rDNA-deficient X chromosomes. These transgene studies, however, do not address requirements for the function of the endogenous rDNA loci within the heterochromatin. Here we describe two chromosome rearrangements that disrupt rDNA functions. Both rearrangements are translocations that cause an extreme bobbed visible phenotype and XY nondisjunction and meiotic drive in males. However, neither rearrangement interacts with a specific Y chromosome, Ymal+, that induces male sterility in combination with rDNA deletions. Molecular studies show that the translocations are not associated with gross rearrangements of the rDNA repeat arrays. Rather, suppression of the bobbed phenotypes by Y heterochromatin suggests that decreased rDNA function is caused by a chromosomal position effect. While both translocations affect rDNA transcription, only one disrupts meiotic XY pairing, indicating that there are different cis-acting requirements for rDNA transcription and rDNA-mediated meiotic pairing.

scholarly journals Transposition of the Responder element (Rsp) of the Segregation distorter system (SD) to the X chromosome in Drosophila melanogaster.

Genetics ◽  
1989 ◽  
Vol 122 (1) ◽  
pp. 81-86 ◽  
Author(s):  
E S Walker ◽  
T W Lyttle ◽  
J C Lucchesi
Keyword(s):  
Drosophila Melanogaster ◽  
Y Chromosome ◽  
X Chromosome ◽  
Meiotic Drive ◽  
Genetic System ◽  
Drive System ◽  
Potential Utility ◽  
X Chromosomes ◽  
Large Numbers ◽  
Segregation Distorter

Abstract In order to test whether the meiotic drive system Segregation distorter (SD) can operate on the X chromosome to exclude it from functional sperm, we have transposed the Responder locus (Rsp) to this element. This was accomplished by inducing detachments of a compound-X chromosome in females carrying a Y chromosome bearing a Rsps allele. Six Responder-sensitive-bearing X chromosomes, with kappa values ranging from 0.90 to 1.00, were established as permanent lines. Two of these have been characterized more extensively with respect to various parameters affecting meiotic drive. SD males with a Responder-sensitive X chromosome produce almost exclusively male embryos, while those with a Rsp-Y chromosome produce almost exclusively female embryos. This provides a genetic system of great potential utility for the study of early sex-specific differentiation events as it allows the collection of large numbers of embryos of a given sex.

scholarly journals A NOTE ON THE MATERNAL EFFECT MUTANTS DAUGHTERLESS AND ABNORMAL OOCYTE IN DROSOPHILA MELANOGASTER

Genetics ◽  
1973 ◽  
Vol 73 (1) ◽  
pp. 73-86
Author(s):  
Arthur P Mange ◽  
L Sandler
Keyword(s):  
Drosophila Melanogaster ◽  
Maternal Effect ◽  
Sex Chromosome ◽  
Chromosome 2 ◽  
Dominant Marker ◽  
Enhancing Effect ◽  
X Irradiation ◽  
The Right ◽  
Chromosome Breakpoint ◽  
Special Region

ABSTRACT Two deficiencies for, and a dominant enhancer of, the second chromosome maternal effect mutant, "daughterless" (da), were induced with X-irradiation. Their properties were studied with respect to both da and the linked maternal effect mutant, "abnormal oocyte" (abo), with the following conclusions. (1) The most probable map positions of da and abo are: J–½–da–2½–abo, where J is a dominant marker located at 41 on the standard map. (2) The da locus is in bands 31CD-F on the polytene chromosome map; abo is to the right of 32A. (3) Because homozygous da individuals survive while individuals carrying da and a deficiency for da are lethal, it is concluded that da is hypomorphic. (4) From a weak da-like maternal effect in heterozygous da females induced by an "Enhancer of da," we have confirmed a previous report that (a) the amount of sex chromosome heterochromatin contributed by the father can influence the severity of the da maternal effect, and (b) the sex chromosome heterochromatin which influences the da effect is different from that which influences the abo effect. (5) The possibility that da and abo are in a special region of chromosome 2 concerned with the regulation of sex chromosome heterochromatin is strengthened by the observation that the Enhancer of da appears to rescue abnormal eggs produced by homozygous abo mothers. (6) The Enhancer of da is a translocation between chromosomes 2 and 3 with the second chromosome breakpoint in the basal heterochromatin; because the enhancing effect maps in this region of chromosome 2, it is possible that autosomal, as well as sex chromosomal, heterochromatin interacts with da and abo.

Multigene Family of Ribosomal DNA in Drosophila melanogaster Reveals Contrasting Patterns of Homogenization for IGS and ITS Spacer Regions: A Possible Mechanism to Resolve This Paradox

Genetics ◽  
1998 ◽  
Vol 149 (1) ◽  
pp. 243-256 ◽  
Author(s):  
Carlos Polanco ◽  
Ana I González ◽  
Álvaro de la Fuente ◽  
Gabriel A Dover
Keyword(s):  
Drosophila Melanogaster ◽  
Concerted Evolution ◽  
Multigene Family ◽  
Natural Populations ◽  
Intergenic Spacer ◽  
Meiotic Pairing ◽  
Y Chromosomes ◽  
Mutation Distribution ◽  
Chromosome Exchanges

Abstract The multigene family of rDNA in Drosophila reveals high levels of within-species homogeneity and between-species diversity. This pattern of mutation distribution is known as concerted evolution and is considered to be due to a variety of genomic mechanisms of turnover (e.g., unequal crossing over and gene conversion) that underpin the process of molecular drive. The dynamics of spread of mutant repeats through a gene family, and ultimately through a sexual population, depends on the differences in rates of turnover within and between chromosomes. Our extensive molecular analysis of the intergenic spacer (IGS) and internal transcribed spacer (ITS) spacer regions within repetitive rDNA units, drawn from the same individuals in 10 natural populations of Drosophila melanogaster collected along a latitudinal cline on the east coast of Australia, indicates a relatively fast rate of X-Y and X-X interchromosomal exchanges of IGS length variants in agreement with a multilineage model of homogenization. In contrast, an X chromosome-restricted 24-bp deletion in the ITS spacers is indicative of the absence of X-Y chromosome exchanges for this region that is part of the same repetitive rDNA units. Hence, a single lineage model of homogenization, coupled to drift and/or selection, seems to be responsible for ITS concerted evolution. A single-stranded exchange mechanism is proposed to resolve this paradox, based on the role of the IGS region in meiotic pairing between X and Y chromosomes in D. melanogaster.

scholarly journals MULTIPLE MEIOTIC DRIVE SYSTEMS IN THE DROSOPHILA MELANOGASTER MALE

Genetics ◽  
1972 ◽  
Vol 72 (1) ◽  
pp. 105-115
Author(s):  
George L Gabor Miklos ◽  
Armon F Yanders ◽  
W J Peacock
Keyword(s):  
Drosophila Melanogaster ◽  
Survival Probability ◽  
Sex Chromosome ◽  
Meiotic Drive ◽  
The Other ◽  
Segregation Distorter ◽  
Two Systems ◽  
Combined Action ◽  
Drive Systems

ABSTRACT The behaviour of two "meiotic drive" systems, Segregation-Distorter (SD) and the sex chromosome sc4sc8 has been examined in the same meiocyte. It has been found that the two systems interact in a specific way. When the distorting effects of SD and sc4sc8 are against each other, there is no detectable interaction. Each system is apparently oblivious to the presence of the other, gametes being produced according to independence expectations. However when the affected chromosomes are at the same meiotic pole an interaction occurs; the survival probability of the gamete containing both distorted chromosomal products is increased, rather than being decreased by the combined action of two systems.

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.

scholarly journals Cytogenetics of Premature Ovarian Failure: An Investigation on 269 Affected Women

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Simona Baronchelli ◽  
Donatella Conconi ◽  
Elena Panzeri ◽  
Angela Bentivegna ◽  
Serena Redaelli ◽  
...  
Keyword(s):  
X Chromosome ◽  
Premature Ovarian Failure ◽  
Ovarian Function ◽  
Sex Chromosome ◽  
Chromosomal Abnormalities ◽  
Population Group ◽  
Ovarian Failure ◽  
Chromosome Mosaicism ◽  
Low Level

The importance of X chromosome in the aetiology of premature ovarian failure (POF) is well-known but in many cases POF still remains idiopathic. Chromosome aneuploidy increase is a physiological phenomenon related to aging, but the role of low-level sex chromosome mosaicism in ovarian function is still undiscovered. Standard cytogenetic analysis was carried out in a total of 269 patients affected by POF: 27 chromosomal abnormalities were identified, including X chromosome and autosomal structural and numerical abnormalities. In 47 patients with 46,XX karyotype we performed interphase FISH using X alpha-satellite probe in order to identify X chromosome mosaicism rate. Aneuploidy rate in the patient group was significantly higher than the general population group. These findings underline the importance of X chromosome in the aetiology of POF and highlight the potential role of low-level sex chromosome mosaicism in ovarian aging that may lead to a premature onset of menopause.

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