scholarly journals Relationship between chromosome content and nuclear diameter in early spermatids of Drosophila melanogaster

1989 ◽  
Vol 54 (3) ◽  
pp. 205-212 ◽  
Author(s):  
Cayetano González ◽  
José Casal ◽  
Pedro Ripoll
Keyword(s):  
Drosophila Melanogaster ◽  
Light Microscopy ◽  
Sex Chromosome ◽  
Chromosome Complement ◽  
Wild Type ◽  
Male Sterile ◽  
Nuclear Diameter ◽  
Early Spermatid ◽  
The Relationship

SummaryWe have studied, using light microscopy, the relationship between chromosome content and nuclear diameter in early spermatids of males carrying different combinations of wild-type and compound chromosomes in Drosophila melanogaster. By using these genotypes we have been able to observe spermatid nuclei bearing various numbers of chromosomes ranging from only one sex chromosome and no major autosomes to almost twice the normal chromosome complement. We have found that variations in the chromosome content are accompanied by increasing the variance in early spermatid nuclear diameter; the more gametic classes produced, the higher the variance of nuclear diameters. These results indicate that measuring nuclear diameters in early spermatids represents a useful way to estimate the levels of meiotic non-disjunction and thereby to improve the characterization of lethal or male sterile mutants in which analysis of meiotic chrosome non-disjunction cannot be achieved by conventional genetic methods.

scholarly journals Genetic and Molecular Characterization of sting, a Gene Involved in Crystal Formation and Meiotic Drive in the Male Germ Line of Drosophila melanogaster

Genetics ◽  
1999 ◽  
Vol 151 (2) ◽  
pp. 749-760 ◽  
Author(s):  
Armin Schmidt ◽  
Gioacchino Palumbo ◽  
Maria P Bozzetti ◽  
Patrizia Tritto ◽  
Sergio Pimpinelli ◽  
...  
Keyword(s):  
Amino Acids ◽  
Drosophila Melanogaster ◽  
Null Allele ◽  
Germ Line ◽  
Meiotic Drive ◽  
P Element ◽  
Crystal Formation ◽  
Male Sterile ◽  
Male Sterile Mutation

Abstract The sting mutation, caused by a P element inserted into polytene region 32D, was isolated by a screen for male sterile insertions in Drosophila melanogaster. This sterility is correlated with the presence of crystals in spermatocytes and spermatids that are structurally indistinguishable from those produced in males carrying a deficiency of the Y-linked crystal (cry) locus. In addition, their morphology is needle-like in Ste+ flies and star-shaped in Ste flies, once again as observed in cry– males. The sti mutation leads to meiotic drive of the sex chromosomes, and the strength of the phenomenon is correlated with the copy number of the repetitive Ste locus. The same correlation is also true for the penetrance of the male sterile mutation. A presumptive sti null allele results in male sterility and lethal maternal effect. The gene was cloned and shown to code for a putative protein that is 866 amino acids long. A C-terminal domain of 82 amino acids is identified that is well conserved in proteins from different organisms. The gene is expressed only in the germline of both sexes. The interaction of sting with the Ste locus can also be demonstrated at the molecular level. While an unprocessed 8-kb Ste primary transcript is expressed in wild-type males, in X/Y homozygous sti males, as in X/Y cry– males, a 0.7-kb mRNA is produced.

Genetic characterization of ms (3) K81, a paternal effect gene of Drosophila melanogaster.

Genetics ◽  
1995 ◽  
Vol 140 (1) ◽  
pp. 219-229 ◽  
Author(s):  
G K Yasuda ◽  
G Schubiger ◽  
B T Wakimoto
Keyword(s):  
Drosophila Melanogaster ◽  
Developmental Stages ◽  
Normal Function ◽  
Loss Of Function ◽  
Male Sterile ◽  
Specific Product ◽  
Paternal Effect ◽  
Developmental Arrest ◽  
Effect Gene

Abstract The vast majority of known male sterile mutants of Drosophila melanogaster fail to produce mature sperm or mate properly. The ms(3) K81(1) mutation is one of a rare class of male sterile mutations in which sterility is caused by developmental arrest after sperm entry into the egg. Previous studies showed that males homozygous for the K81(1) mutation produce progeny that arrest at either of two developmental stages. Most embryos arrest during early nuclear cycles, whereas the remainder are haploid embryos that arrest at a later stage. This description of the mutant phenotype was based on the analysis of a single allele isolated from a natural population. It was therefore unclear whether this unique paternal effect phenotype reflected the normal function of the gene. The genetic analysis and initial molecular characterization of five new K81 mutations are described here. Hemizygous conditions and heteroallelic combinations of the alleles were associated with male sterility caused by defects in embryogenesis. No other mutant phenotypes were observed. Thus, the K81 gene acted as a strict paternal effect gene. Moreover, the biphasic pattern of developmental arrest was common to all the alleles. These findings strongly suggested that the unusual embryonic phenotype caused by all five new alleles was due to loss of function of the K81+ gene. The K81 gene is therefore the first clear example of a strict paternal effect gene in Drosophila. Based on the embryonic lethal phenotypes, we suggest that the K81+ gene encodes a sperm-specific product that is essential for the male pronucleus to participate in the first few embryonic nuclear divisions.

ON THE IDENTIFICATION OF THE ROSY LOCUS DNA IN DROSOPHILA MELANOGASTER: INTRAGENIC RECOMBINATION MAPPING OF MUTATIONS ASSOCIATED WITH INSERTIONS AND DELETIONS

Genetics ◽  
1986 ◽  
Vol 112 (4) ◽  
pp. 755-767
Author(s):  
S H Clark ◽  
M McCarron ◽  
C Love ◽  
A Chovnick
Keyword(s):  
Drosophila Melanogaster ◽  
Large Scale ◽  
Conclusive Evidence ◽  
Hybrid Dysgenesis ◽  
Intragenic Recombination ◽  
Wild Type ◽  
Structural Element ◽  
Insertions And Deletions ◽  
Recombination Mapping

ABSTRACT DNA extracts of several rosy-mutation-bearing strains were associated with large insertions and deletions in a defined region of the molecular map believed to include the rosy locus DNA. Large-scale, intragenic mapping experiments were carried out that localized these mutations within the boundaries of the previously defined rosy locus structural element. Molecular characterization of the wild-type recombinants provides conclusive evidence that the rosy locus DNA is localized to the DNA segment marked by these lesions.—One of the mutations, ry  2101, arose from a P-M hybrid dysgenesis experiment and is associated with a copia insertion. Experiments are described which suggest that copia mobilizes in response to P-M hybrid dysgenesis.—Relevance of the data to recombination in higher organisms is considered.

Two karyotypes and heteromorphic sex chromosomes in Physalaemus petersi (Anura, Leptodactylidae)

1999 ◽  
Vol 77 (4) ◽  
pp. 624-631 ◽  
Author(s):  
Luciana B Lourenço ◽  
Shirlei M Recco-Pimentel ◽  
Adão J Cardoso
Keyword(s):  
Meiotic Division ◽  
Sex Chromosome ◽  
Chromosome Complement ◽  
Heteromorphic Sex Chromosomes ◽  
Karyological Evolution ◽  
Cytogenetic Analyses ◽  
Sex Chromosome System ◽  
Relationship Of ◽  
The Relationship ◽  
Two Populations

Cytogenetic analyses were performed on specimens from two populations of Physalaemus petersi from three locations in Brazilian West Amazon. Chromosomes from the testis and intestinal epithelium were stained conventionally with Giemsa or C-banded. All animals studied showed a full chromosome complement of 2n = 22, but two distinct karyotypes (I and II) were detected among specimens from one of the populations. Karyotype I specimens showed a XX/XY sex chromosome system and C-band polymorphism. Bivalent chromosomes with heterozygous C-banding frequently lacked chiasmata in the region of this heterochromatin during the first meiotic division. The less common karyotype (II) had a heteromorphic pair of chromosomes, but the relationship of this pair to sex determination could not be elucidated because of the absence of female specimens. Karyotype II was observed in males whose call differed from those of other males in the same population, suggesting that a reevaluation of the taxon P. petersi may be necessary. These results suggest that, in these populations, karyological evolution occurs faster than anatomical evolution.

scholarly journals Sterility-mutability correlation: On the correlation between sterility and mutability during P-M hybrid dysgenesis in Drosophila melanogaster

1987 ◽  
Vol 50 (1) ◽  
pp. 73-76 ◽  
Author(s):  
Gail M. Simmons
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Population ◽  
Gonadal Dysgenesis ◽  
Hybrid Dysgenesis ◽  
Positive Correlations ◽  
The Relationship

SummaryTwelve isogenic X chromosome lines from a single natural population of Drosophila melanogaster were tested for their potential to induce gonadal dysgenesis and singed-weak mutability in P-M hybrid dysgenesis. The correlation between sterility and mutability was significantly positive for Cross A, confirming the results reported by Engels (1984) and Kocur, Drier & Simmons (1986). In Cross A* cytotype tests, however, two of the lines gave strikingly different results when measured by the gonadal dysgenesis test as compared to the singed-weak test. Positive correlations between traits within a given line were generally not observed. The results suggest that the relationship between gonadal dysgenesis production and the mobilization of P elements in singed-weak mutability is more complicated than that proposed by Engels (1984). The two phenomena may be separable under certain conditions. Neither test can be taken as an adequate characterization of the hybrid dysgenesis ‘profile’ of a line of flies.

Characterization of microsomal oxidative activities in a wild-type and in a DDT resistant strain of Drosophila melanogaster

1990 ◽  
Vol 37 (3) ◽  
pp. 293-302 ◽  
Author(s):  
André Cùany ◽  
Madeleine Pralavorio ◽  
David Pauron ◽  
Jean Baptiste Berge ◽  
Didier Fournier ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Resistant Strain ◽  
Wild Type

scholarly journals Isolation and Cytogenetic Characterization of Male Meiotic Mutants of Drosophila melanogaster

Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1795-1806
Author(s):  
Kazuyuki Hirai ◽  
Satomi Toyohira ◽  
Takashi Ohsako ◽  
Masa-Toshi Yamamoto
Keyword(s):  
Drosophila Melanogaster ◽  
Sex Chromosome ◽  
Male Meiosis ◽  
Fourth Chromosome ◽  
Homologous Chromosomes ◽  
Meiotic Mutants ◽  
Chromatid Cohesion ◽  
Cytogenetic Characterization ◽  
Meiosis I

Abstract Proper segregation of homologous chromosomes in meiosis I is ensured by pairing of homologs and maintenance of sister chromatid cohesion. In male Drosophila melanogaster, meiosis is achiasmatic and homologs pair at limited chromosome regions called pairing sites. We screened for male meiotic mutants to identify genes required for normal pairing and disjunction of homologs. Nondisjunction of the sex and the fourth chromosomes in male meiosis was scored as a mutant phenotype. We screened 2306 mutagenized and 226 natural population-derived second and third chromosomes and obtained seven mutants representing different loci on the second chromosome and one on the third. Five mutants showed relatively mild effects (<10% nondisjunction). mei(2)yh149 and mei(2)yoh7134 affected both the sex and the fourth chromosomes, mei(2)yh217 produced possible sex chromosome-specific nondisjunction, and mei(2)yh15 and mei(2)yh137 produced fourth chromosome-specific nondisjunction. mei(2)yh137 was allelic to the teflon gene required for autosomal pairing. Three mutants exhibited severe defects, producing >10% nondisjunction of the sex and/or the fourth chromosomes. mei(2)ys91 (a new allele of the orientation disruptor gene) and mei(3)M20 induced precocious separation of sister chromatids as early as prometaphase I. mei(2)yh92 predominantly induced nondisjunction at meiosis I that appeared to be the consequence of failure of the separation of paired homologous chromosomes.

Interaction between the Cig1 and Cig2 B-type cyclins in the fission yeast cell cycle

1994 ◽  
Vol 14 (1) ◽  
pp. 768-776
Author(s):  
T Connolly ◽  
D Beach
Keyword(s):  
Cell Cycle ◽  
Fission Yeast ◽  
Null Allele ◽  
Wild Type Strain ◽  
Periodic Oscillation ◽  
S Phase ◽  
Wild Type ◽  
Nuclear Separation ◽  
The Relationship

In this report, we describe the cloning and characterization of a B-type cyclin, Cig2 from the fission yeast Schizosaccharomyces pombe. The cig2 gene encodes a 45-kDa protein that is most similar to a previously identified B-type cyclin in S. pombe, Cdc13. Deletion of cig2 had no observable effect on cell viability or progression through the cell cycle. Strains carrying the cig2 null allele do, however, exhibit an enhanced ability to undergo conjugation relative to a wild-type strain. The cig2 transcript was found to undergo periodic oscillation during the cell cycle, peaking at the G1/S-phase boundary. We have investigated the relationship between Cig2 and the other B-type cyclins, Cig1 and Cdc13, in the fission yeast. We found that cells carrying disruptions of both the cig1 and cig2 genes contain multiple nuclei with a 1C DNA content, suggesting that they are delayed in progression through the G1 phase of the cell cycle. The phenotype of this double mutant suggests that there is a delay in septum formation, possibly as a result of defective nuclear separation.

scholarly journals Interaction between the Cig1 and Cig2 B-type cyclins in the fission yeast cell cycle.

1994 ◽  
Vol 14 (1) ◽  
pp. 768-776 ◽  
Author(s):  
T Connolly ◽  
D Beach
Keyword(s):  
Cell Cycle ◽  
Fission Yeast ◽  
Null Allele ◽  
Wild Type Strain ◽  
Periodic Oscillation ◽  
S Phase ◽  
Wild Type ◽  
Nuclear Separation ◽  
The Relationship

In this report, we describe the cloning and characterization of a B-type cyclin, Cig2 from the fission yeast Schizosaccharomyces pombe. The cig2 gene encodes a 45-kDa protein that is most similar to a previously identified B-type cyclin in S. pombe, Cdc13. Deletion of cig2 had no observable effect on cell viability or progression through the cell cycle. Strains carrying the cig2 null allele do, however, exhibit an enhanced ability to undergo conjugation relative to a wild-type strain. The cig2 transcript was found to undergo periodic oscillation during the cell cycle, peaking at the G1/S-phase boundary. We have investigated the relationship between Cig2 and the other B-type cyclins, Cig1 and Cdc13, in the fission yeast. We found that cells carrying disruptions of both the cig1 and cig2 genes contain multiple nuclei with a 1C DNA content, suggesting that they are delayed in progression through the G1 phase of the cell cycle. The phenotype of this double mutant suggests that there is a delay in septum formation, possibly as a result of defective nuclear separation.

Meiosis in Drosophila melanogaster. V. Univalent behavior in In(1)sc4Lsc8R/BsY males

1984 ◽  
Vol 26 (4) ◽  
pp. 445-458 ◽  
Author(s):  
H-P. P. Lin ◽  
J. G. Ault ◽  
M. Kimble ◽  
K. Church
Keyword(s):  
Electron Microscopy ◽  
Drosophila Melanogaster ◽  
Light Microscopy ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Unbiased Manner ◽  
Section Electron ◽  
Serial Section Electron Microscopy ◽  
Section Electron Microscopy ◽  
Chromosome Nondisjunction

Univalent behavior during meiosis has been examined in Drosophila melanogaster males possessing the In(1)sc4Lsc8R X chromosome using light microscopy and serial section electron microscopy. Males from two stocks, displaying high (0.40) and low (0.14) frequencies of sex chromosome nondisjunction, have been investigated. The results demonstrate that (i) sex chromosomes are more intimately paired during prometaphase 1 in males from the low nondisjunction stock than in males from the high nondisjunction stock, and (ii) the univalents are distributed to the poles in an unbiased manner during meiosis rather than by directed segregation of both univalents to the same pole as previously determined for other In(1)sc4Lsc8R/Y males. Kewords: Drosophila melanogaster, meiosis, univalent behavior, In(1)sc4Lsc8R/BsY males.

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