Genetic analysis of Stellate elements of Drosophila melanogaster.

Abstract Repeated elements are remarkably important for male meiosis and spermiogenesis in Drosophila melanogaster. Pairing of the X and Y chromosomes is mediated by the ribosomal RNA genes of the Y chromosome and X chromosome heterochromatin, spermiogenesis depends on the fertility factors of the Y chromosome. Intriguingly, a peculiar genetic system of interaction between the Y-linked crystal locus and the X-linked Stellate elements seem to be also involved in male meiosis and spermiogenesis. Deletion of the crystal element of the Y, via an interaction with the Stellate elements of the X, causes meiotic abnormalities, gamete-genotype dependent failure of sperm development (meiotic drive), and deposition of protein crystals in spermatocytes. The current hypothesis is that the meiotic abnormalities observed in cry- males is due to an induced overexpression of the normally repressed Ste elements. An implication of this hypothesis is that the strength of the abnormalities would depend on the amount of the Ste copies. To test this point we have genetically and cytologically examined the relationship of Ste copy number and organization to meiotic behavior in cry- males. We found that heterochromatic as well as euchromatic Ste repeats are functional and that the abnormality in chromosome condensation and the frequency of nondisjunction are related to Ste copy number. Moreover, we found that meiosis is disrupted after synapsis and that cry-induced meiotic drive is probably not mediated by Ste.

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Variation in Y Chromosome Segregation in Natural Populations of Drosophila melanogaster

Genetics ◽

10.1093/genetics/115.1.143 ◽

1987 ◽

Vol 115 (1) ◽

pp. 143-151

Author(s):

Andrew G Clark

Keyword(s):

Drosophila Melanogaster ◽

Y Chromosome ◽

Chromosome Segregation ◽

Significant Variation ◽

Natural Populations ◽

Meiotic Drive ◽

Adult Offspring ◽

Functional Variation ◽

Y Chromosomes ◽

Geographic Origins

ABSTRACT Functional variation among Y chromosomes in natural populations of Drosophila melanogaster was assayed by a segregation study. A total of 36 Y chromosomes was extracted and ten generations of replacement backcrossing yielded stocks with Y chromosomes in two different genetic backgrounds. Eleven of the Y chromosomes were from diverse geographic origins, and the remaining 25 were from locally captured flies. Segregation of sexes in adult offspring was scored for the four possible crosses among the two backgrounds with each Y chromosome. Although the design confounds meiotic drive and effects on viability, statistical partitioning of these effects reveals significant variation among lines in Y chromosome segregation. Results are discussed in regards to models of Y-linked segregation and viability effects, which suggest that Y-linked adaptive polymorphism is unlikely.

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

Genetics ◽

10.1093/genetics/122.1.81 ◽

1989 ◽

Vol 122 (1) ◽

pp. 81-86 ◽

Cited By ~ 1

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.

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ORGANIZATION AND MAPPING OF A SEQUENCE ON THE DROSOPHILA MELANOGASTER X AND Y CHROMOSOMES THAT IS TRANSCRIBED DURING SPERMATOGENESIS

Genetics ◽

10.1093/genetics/107.4.611 ◽

1984 ◽

Vol 107 (4) ◽

pp. 611-634 ◽

Cited By ~ 1

Author(s):

Kenneth J Livak

Keyword(s):

Drosophila Melanogaster ◽

Y Chromosome ◽

X Chromosome ◽

Base Pair ◽

Copy Number ◽

Wild Type ◽

Recombinant Phage ◽

Restriction Fragments ◽

Y Chromosomes ◽

Low Copy Number

ABSTRACT The D. melanogaster DNA segment in the recombinant phage λDm2L1 contains at least eight copies of a tandemly repeated 1250-base pair (bp) sequence (henceforth called the 2L1 sequence). Testes from XO D. melanogaster males contain an abundant 800-base RNA species that is homologous to a 520-bp region of the 2L1 sequence. Blotting experiments show that the 2L1 sequence is repeated in the D. melanogaster genome and is present on both the X and Y chromosomes. With the use of X-Y translocations, the 2L1 sequence has been mapped to a region between kl-1 and kl-2 on the long arm of the Y chromosome. In Oregon-R wild type there are an estimated 200 copies of the 2L1 sequence on the X chromosome and probably at least 80 copies on the Y chromosome. In some other strains the repetition frequency on the Y chromosome is about the same, but the copy number on the X chromosome is much reduced. On the basis of the five strains investigated, there is a correlation between copy number of the 2L1 sequence on the X chromosome and the presence of a particular allele of the Stellate locus (Ste; 1-45.7). It seems that low copy number corresponds to Ste + and high copy number corresponds to Ste. The Ste locus determines whether single or star-shaped crystals are observed in the spermatocytes of XO males. Studies using D. simulans and D. mauritiana DNA show that the 2L1 sequence is homologous to restriction fragments in male DNA but not female DNA, indicating that this sequence is present only on the Y chromosome in these two species. In DNA derived from D. erecta, D. teissieri and D. yakuba, there is very little, if any, hybridization with the 2L1 sequence probe.

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Ribosomal DNA and Stellate gene copy number variation on the Y chromosome of Drosophila melanogaster.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.86.6.1944 ◽

1989 ◽

Vol 86 (6) ◽

pp. 1944-1948 ◽

Cited By ~ 51

Author(s):

E. M. Lyckegaard ◽

A. G. Clark

Keyword(s):

Drosophila Melanogaster ◽

Copy Number Variation ◽

Y Chromosome ◽

Ribosomal Dna ◽

Copy Number ◽

Gene Copy Number ◽

Gene Copy ◽

Gene Copy Number Variation ◽

Number Variation

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DoesStellateCause Meiotic Drive inDrosophila melanogaster?

Genetics ◽

10.1093/genetics/161.4.1551 ◽

2002 ◽

Vol 161 (4) ◽

pp. 1551-1559 ◽

Cited By ~ 1

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.

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Y CHROMOSOME HYPERPLOIDY AND MALE FERTILITY IN DROSOPHILA MELANOGASTER

Canadian Journal of Genetics and Cytology ◽

10.1139/g79-003 ◽

1979 ◽

Vol 21 (1) ◽

pp. 21-24 ◽

Cited By ~ 5

Author(s):

John H. Williamson ◽

Eva Meidinger

Keyword(s):

Drosophila Melanogaster ◽

Y Chromosome ◽

Mating Behavior ◽

Male Fertility ◽

Y Chromosomes

Drosophila melanogaster males with two supernumerary Y chromosomes, i.e. triplo-Y males, are completely sterile. Their mating behavior is normal, and spermatogenesis and spermiogenesis appear normal, but no sperm are transferred. Most, if not all, of the detrimental effects of a third Y chromosome on male fertility are attributable to the long arm of the Y chromosome.

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Are Unpaired Chromosomes Spermicidal?: A Maximum-Likelihood Analysis of Segregation and Meiotic Drive in Drosophila melanogaster Males Deficient for the Ribosomal-DNA

Genetics ◽

10.1093/genetics/151.1.251 ◽

1999 ◽

Vol 151 (1) ◽

pp. 251-262 ◽

Cited By ~ 3

Author(s):

Leonard G Robbins

Keyword(s):

Drosophila Melanogaster ◽

Maximum Likelihood ◽

Physical State ◽

Meiotic Drive ◽

Direct Connection ◽

Maximum Likelihood Analysis ◽

Likelihood Analysis ◽

Sperm Development ◽

Sperm Survival ◽

Sperm Chromosomes

AbstractMeiosis in Drosophila melanogaster males is achiasmate and requires special systems to ensure normal segregation. Several situations that yield frequent nondisjunction also produce high levels of chromatin-dependent sperm lethality, suggesting the possibility of a simple and direct connection between defective disjunction and defective sperm development. One hypothesis that has been offered is that pairing not only ensures disjunction, but also changes the physical state of chromosomes so that they can be packaged in sperm. Here, I present an analysis of extensive data on disjunction and sperm survival in rDNA-deficient males collected by B. McKee and D. Lindsley. This analysis demonstrates that, although nondisjunction and sperm lethality are indeed correlated, the basis of this is not the presence of unpaired chromosomes in the sperm. Chromosomes that have failed to disjoin are not themselves spermicidal.

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The Y chromosome of Drosophila melanogaster contains a distinctive subclass of Het-A-related repeats.

Genetics ◽

10.1093/genetics/134.2.531 ◽

1993 ◽

Vol 134 (2) ◽

pp. 531-543 ◽

Cited By ~ 3

Author(s):

O Danilevskaya ◽

A Lofsky ◽

E V Kurenova ◽

M L Pardue

Keyword(s):

Drosophila Melanogaster ◽

Transposable Element ◽

Y Chromosome ◽

Tandem Repeats ◽

Chromosome Analysis ◽

Sequence Identity ◽

Y Chromosomes ◽

Transposition Mechanism

Abstract The HeT-A element is a transposable element with an apparent role in the structure of the telomeres of Drosophila melanogaster chromosomes. HeT-A transposition is the earliest event detected in healing of broken ends; HeT-A is also found on telomeres of unbroken chromosomes. Sequences with homology to HeT-A are never detected in euchromatic regions; however, clusters of HeT-A-related sequences occur in nontelomeric regions of the heterochromatic Y chromosome. Analysis of two of these Y-associated clusters shows them to be significantly different in structure from telomeric HeT-A elements, although the regions of shared sequence have > 80% sequence identity in all cases. Telomeric HeT-A elements occur in chains, with the elements in the same orientation but variably truncated at their external ends and irregularly interspersed with unrelated sequences. In contrast, the nontelomeric Y elements are regular tandem repeats of parts of the HeT-A sequence joined to unrelated sequences which are not the same in the two clusters studied. The sequence structures suggest that the nontelomeric clusters on the Y chromosome do not arise by the same transposition mechanism that forms the telomeric clusters; instead the clusters on the Y may arise by a mechanism that is used more generally in the evolution of Y chromosomes. Although the telomeric and nontelomeric clusters appear to be formed differently, both are enriched in parts of the HeT-A sequence which may be important in the structure of heterochromatin.

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Distinct spermiogenic phenotypes underlie sperm elimination in the Segregation Distorter meiotic drive system

PLoS Genetics ◽

10.1371/journal.pgen.1009662 ◽

2021 ◽

Vol 17 (7) ◽

pp. e1009662

Author(s):

Marion Herbette ◽

Xiaolu Wei ◽

Ching-Ho Chang ◽

Amanda M. Larracuente ◽

Benjamin Loppin ◽

...

Keyword(s):

Drosophila Melanogaster ◽

Satellite Dna ◽

Copy Number ◽

Meiotic Drive ◽

Drive System ◽

Sperm Chromatin ◽

Cellular Mechanisms ◽

Segregation Distorter ◽

Sperm Nuclei ◽

Very High

Segregation Distorter (SD) is a male meiotic drive system in Drosophila melanogaster. Males heterozygous for a selfish SD chromosome rarely transmit the homologous SD+ chromosome. It is well established that distortion results from an interaction between Sd, the primary distorting locus on the SD chromosome and its target, a satellite DNA called Rsp, on the SD+ chromosome. However, the molecular and cellular mechanisms leading to post-meiotic SD+ sperm elimination remain unclear. Here we show that SD/SD+ males of different genotypes but with similarly strong degrees of distortion have distinct spermiogenic phenotypes. In some genotypes, SD+ spermatids fail to fully incorporate protamines after the removal of histones, and degenerate during the individualization stage of spermiogenesis. In contrast, in other SD/SD+ genotypes, protamine incorporation appears less disturbed, yet spermatid nuclei are abnormally compacted, and mature sperm nuclei are eventually released in the seminal vesicle. Our analyses of different SD+ chromosomes suggest that the severity of the spermiogenic defects associates with the copy number of the Rsp satellite. We propose that when Rsp copy number is very high (> 2000), spermatid nuclear compaction defects reach a threshold that triggers a checkpoint controlling sperm chromatin quality to eliminate abnormal spermatids during individualization.

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MITOTIC RECOMBINATION IN THE HETEROCHROMATIN OF THE SEX CHROMOSOMES OF DROSOPHILA MELANOGASTER

Genetics ◽

10.1093/genetics/90.1.93 ◽

1978 ◽

Vol 90 (1) ◽

pp. 93-104

Author(s):

P Ripoll ◽

A Garcia-Bellido

Keyword(s):

Drosophila Melanogaster ◽

Y Chromosome ◽

Sex Chromosomes ◽

Mitotic Recombination ◽

X Chromosomes ◽

X Ray ◽

Y Chromosomes ◽

Chromosome Arm

ABSTRACT The frequency of spontaneous and X-ray-induced mitotic recombination involving the Y chromosome has been studied in individuals with a marked Y chromosome arm and different XY compound chromosomes. The genotypes used include X chromosomes with different amounts of X heterochromatin and either or both arms of the Y chromosome attached to either side of the centromere. Individuals with two Y chromosomes have also been studied. The results show that the bulk of mitotic recombination takes place between homologous regions.

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