Males ofDrosophila Melanogaster Research Articles

Absence of resistance genes against male-killing action of the SRO in Drosophila melanogaster.

Males of Drosophila melanogaster bearing various X chromosome segmental aneuploidies were tested for sensitivity/resistance to the male killing action of the Sex Ratio Organism (SRO). It was found that there is no region on the X chromosome which makes, when duplicated, males resistant to the SRO. A region which makes hetero-deficient females sensitive to the SRO also was not found. Searches for a gene (s) that can give males resistance to the SRO action were made using the X chromosomes continuously mutagenized for seven successive generations, the second and third chromosomes obtained from a natural population (100 lines), and the cytoplasm of 100 isofemale lines and twenty-two mass lines from various natural populations. No such genes were recovered. A possible reason for the failure of recovering such a gene is discussed.

SPERM DEPENDENCE OF FEMALE RECEPTIVITY TO REMATING IN DROSOPHILA MELANOGASTER.

As a consequence of copulation, males of Drosophila melanogaster induce a variety of physiological and behavioral effects in the female. Egg production and oviposition are stimulated by products of the male's accessory glands (Kummer, 1960; Garcia-Bellido, 1964; Merle, 1968; Bumet et al., 1973), and female attractiveness and receptivity are both reduced following copulation. Changes in female attractiveness are mediated pheromonally. A change in pheromonal profile from courtship-eliciting to courtship-discouraging pheromones is induced during the first 3 min of (Tompkins et al., 1980; Tompkins and Hall, 1981; Venard and Jallon, 1980). The seminal fluid enzyme esterase-6 metabolizes the seminal fluid component cis-vaccenyl acetate to produce the antiaphrodisiac cis-vaccenyl alcohol (Mane et al., 1983). Behavioral effects of this metabolite on female attractiveness have been demonstrated and have been shown to be short-lived. There is a close correspondence between the time course of these behavioral effects and those first identified by Manning (1967) as the copulation effect. Manning (1962, 1967) also identified a on female receptivity which is longer lasting and causes females to remain unreceptive to male courtship. The strength of the sperm effect seems to be proportional to the number of sperm in storage (Gromko and Pyle, 1978; Gromko et al., 1984). The sperm effect is characterized behaviorally by the use of ovipositor extrusion to reject males, a behavior used only in very low frequency by virgin females (Connolly and Cook, 1973; Tompkins and Hall, 1981). The -or the sperm dependence of the return of female receptivity-is not evident when mated females are confined with second males continuously for 24 h (Newport and Gromko, 1984). In this paper we investigate the details of the sperm dependence of female receptivity within the context of an experimental design which allows females periodic interactions with second males. We also quantify the impact of sperm-dependent female receptivity on the reproductive outcome of double matings. We show that by causing females to delay remating, first males suffer very little reduction in reproductive success due to female remating.

Mutagenic activity of the pyrrolizidine alkaloids seneciphylline and senkirkine in drosophila and their transfer into rat milk

Seneciphylline and senkirkine, two pyrrolizidine alkaloids that occur in animal feeds and medicinal herbs, respectively, have been tested for their ability to produce sex-linked recessive lethals in males of Drosophila melanogaster using the Basc test (3-day feeding method). Seneciphylline was found to be mutagenic at concentrations of 10 −5, 10 −4 and 10 −3 m, which produced 3.8% sex-linked recessive lethals (983 chromosomes tested), 9.0% (708) and 15.3% (327), respectively. Senkirkine (10 −5 m) produced 4.4% sex-linked recessive lethals (2541 chromosomes tested) against 0.17% (9081) in controls. Brood pattern analysis with senkirkine showed maximum sensitivity in the late spermatid stage of spermatogenesis, which agrees with evidence that pyrrolizidine alkaloids act as indirect mutagens. Flies fed with milk from lactating rats given an oral dose of 25 mg seneciphylline/kg showed 1.2% sex-linked recessive lethals (1477 chromosomes tested), against 0.3% (1533) in controls.

Chromosome loss induced by cyclophosphamide in ring-X males of Drosophila melanogaster

Chromosome loss induced by cyclophosphamide in ring-X males of Drosophila melanogaster

A translocation X;Y system for detecting meiotic nondisjunction and chromosome breakage in males of Drosophila melanogaster.

A nondisjunction and chromosome breakage screening system devised by Craymer and modified in our laboratory, involves an X;Y translocation with the short arm of the Y (Ys), marked with the wild type allele of yellow, attached to the distal end of an X (break point 11D) carrying the recessive marker y; and the long arm of the Y chromosome (YL), marked with the dominant locus Bar of Stone (BS), attached to the proximal end of the X. A female tester strain carrying normal chromosomes homozygous for the yellow allele is employed in the mating scheme. Following normal disjunction in the male, all zygotes, which in this case receive aneuploid paternal sex-chromosomes and a normal euploid maternal complement, will die as a result of genetic imbalance. Thus all survivors from this corss can be classified as exceptions arising from: (1) nondisjunction in the female; (2) gross deletion of the paternal X;Y chromosome; (3) complete loss of the paternal X;Y chromosome; or (4) primary meiotic nondisjunction in the male. Results indicate the sensitivity of this scheme for the detection of events induced by x-rays and various chemicals. Positive results have been obtained with the known mutagens EMS and x-radiation.

DNA DISTRIBUTION IN SPERMATID NUCLEI OF NORMAL AND SEGREGATION DISTORTER MALES OF DROSOPHILA MELANOGASTER

Using the DNA-specific dye BAO [2,5-bis-(4'-aminophenyl-(1')]-1,3,4-oxadiazol), we have examined spermiogenesis in wild-type males of Drosophila melanogaster and in males carrying various combinations of the Sd and Rsp mutations involved in segregation distortion. Wild-type strains, even those newly collected from nature, are heterogeneous with respect to the incidence of spermiogenic abnormalities, principally in having a variable number of spermatid nuclei per cyst that fail to undergo complete elongation. Among segregation distorter males, Rsp/Rsp homozygotes have the greatest incidence of nuclear nonelongation or incomplete elongation, Rsp/Rsp( +) heterozygotes are intermediate, while Rsp(+)/ Rsp(+) homozygotes have the least amount of abnormality. Indeed, Sd Rsp(+)/Sd(+)Rsp(+) males have significantly fewer spermiogenic aberrations than do wild-type strains.

An analysis of spontaneous recombination in Drosophila melanogaster males

Spontaneous second chromosome recombination has been observed in males of Drosophila melanogaster newly derived from natural populations. From a Cambridge, England, natural population, two lines out of 20 showed male recombination, and in an Oklahoma, U.S.A., natural population all of 25 lines showed male recombination. One line, OK1, was characterised in more detail, and it was observed that male recombination was probably caused by dominant second and dominant third chromosome elements. The majority of recombination events in the second chromosome occurred in the centromeric region and in the right arm, and male recombinants were recovered in clusters, suggesting that some male recombination occurs in premeiotic cells. Since both single and multiple recombinants were recovered, it was possible to measure chromosome interference for male recombination. This interference was observed to be negative. Finally, there is a reciprocal-cross effect associated with male recombination and F1 female sterility in the OK1 line. This effect on male recombination is apparently not caused by a cytoplasmic suppressor of recombination. The genetic basis and mechanism of male recombination are discussed, along with its possible influence on adaptability in natural populations.

Induction of male recombination in Drosophila melanogaster by injection of extracts of flies showing male recombination.

MORGAN1,2 was the first to report that no spontaneous recombination occurs in males of Drosophila melanogaster. Since then recombination has been induced in D. melanogaster males by various treatments3, for example, X rays. In an attempt to study the control of recombination in D. melanogaster, Reddi et al.4 injected males with ovarian extracts and, surprisingly, induced recombination. Subsequent attempts to repeat this experiment failed5,6. It is known that some natural populations of D. melanogaster show spontaneous male recombination7–10, and it has been suggested that this may be caused by episomes or viruses8,9,11. It is therefore possible that these male recombination-inducing factors could be transferred by injection, and that the failure to reproduce these results4 might have been due to the use of strains lacking such factors. We have therefore tested whether or not male recombination could be induced by injecting extracts of flies from strains showing male recombination into flies lacking male recombination.

The attractiveness to males of female Drosophila melanogaster: Effects of mating, age and diet

Decapitated females were used to examine the attractiveness to males (duration of courtship elicited) of female Drosophila melanogaster. Decapitated females show but few behavioural responses. The attractiveness of virgin females varied with age, being at a maximum on the day of eclosion, and declining thereafter. Even though decapitated inseminated females do not extrude their genitalia they received less courtship than decapitated virgin females. In protein-fed inseminated females attractiveness to males returned in parallel with sexual receptivity. A sucrose diet rendered both virgin and inseminated decapitated females more attractive to males, but did not prevent the change in attractiveness due to mating. The ejaculate and ovarian activation are suggested as causal factors in these processes.

Cytological observations on mitotic and meiotic pairing in males ofDrosophila melanogaster withIn(1)sc 4 sc 8

A cytological study has been carried out on the pairing of the XY chromosomes in somatic cells and in spermatocytes of larvae ofDrosophila melanogaster. Two strains have been studied: one a control strain and the other a carrier of theIn(1)sc4sc8 inversion on the X chromosome. The data obtained seem to indicate that the absence of the greater region of homology between XY, caused by the presence of theIn(1)sc4sc8 inversion, results in an approximately equal reduction in the frequencies of mitotic and meiotic pairing of XY. The short arm of the Y chromosome shows marked differences in the pairing with the X chromosome, compared with the control, whereas the long arm shows no variations.

Autosomal recombination in males ofDrosophila melanogaster caused by a transmissible factor

The phenomenon of male recombination has been found in more than twenty per cent of lines derived from wild-caughtDrosophila melanogaster. The recombination appears to be caused by a factor which is attached to, and transmitted with chromosomes, but which is readily transposed to other chromosomes. The possibility exists, however, that the factor is also capable of independent existence in the nucleoplasm. Extensive testing indicates that the factor is not contagious. The factor has been named “Male Recombinant Factor” or “MRF”.

Genetically based behaviour patterns in Drosophila melanogaster.

SOME time ago Bastock1 demonstrated that yellow (y) mutant males of Drosophila melanogaster had reduced success in fertilising normal females. This tendency of females to reject y males provides a means by which variation in behaviour between populations might be easily studied.

Some genetic aspects of meiosis in males of Drosophila melanogaster, carriers of In(1)sc 4 sc 8

In order to verify the theory of non-homologous pairing in the male meiotic metaphase of Drosophila melanogaster, particular crosses were carried out with In(1)sc 4 sc 8 males, with or without the inversion In(2)SM 5, Cy on the second chromosome. The results seem to indicate the existence of the above mechanisms, which would appear to contribute, not infrequently, to the overall non-disjunction of the In(1)sc 4 sc 8+Cy males.

Untersuchungen über mutagenität und toxizität von Captan bei Drosophila

Captan, a fungicide, was tested for mutagenicity and toxicity in adult males of Drosophila melanogaster. A potent mutagen, the alkylating agent Trenimon, was used as a positive control. Captan was applied to the flies in two different ways and in various solvents. Toxicity was estimated from the ratios of induced mortality and sterility of the treated males. Mutagenicity was determined from the frequencies of sex-linked recessive lethals in pre- and post-meiotic germ cell stages scored with the Basc method. Trenimon was found to be highly mutagenic at a non-toxic concentration. Captan, however, was not mutagenic either at low, non-toxic or at high, toxic concentrations. Even in combination with the solvent dimethyl sulfoxide Captan showed no mutagenicity. Captan is also not mutagenic in maize and mice as shown by various authors. In contrast to this, mutagenic activity of Captan has been demonstrated in the host-mediated assay, Neurospora, yeast, different tissue cultures and bacteria. To explain the discrepancy between our results and those found in other organisms we assume that, in Drosophila, Captan is inactivated before it reaches the germ cells.

Untersuchungen über mutagenität und toxizität von captan bei drosophila

Captan, a fungicide, was tested for mutagenicity and toxicity in adult males of Drosophila melanogaster . A potent mutagen, the alkylating agent Trenimon, was used as a positive control. Captan was applied to the flies in two different ways and in various solvents. Toxicity was estimated from the ratios of induced mortality and sterility of the treated males. Mutagenicity was determined from the frequencies of sex-linked recessive lethals in pre- and post-meiotic germ cell stages scored with the Basc method. Trenimon was found to be highly mutagenic at a non-toxic concentration. Captan, however, was not mutagenic either at low, non-toxic or at high, toxic concentrations. Even in combination with the solvent dimethyl sulfoxide Captan showed no mutagenicity. Captan is also not mutagenic in maize and mice as shown by various authors. In contrast to this, mutagenic activity of Captan has been demonstrated in the host-mediated assay, Neurospora, yeast, different tissue cultures and bacteria. To explain the discrepancy between our results and those found in other organisms we assume that, in Drosophila, Captan is inactivated before it reaches the germ cells.

Induction by 5-bromodeoxyuridine of sex-linked lethal mutations in spermatogenous cells of Drosophila melanogaster

Abstract Injection of adult males of Drosophila melanogaster with a solution of 5-bromodeoxyuridine (BUdR) induced sex-linked lethal mutations but no chromosomal rerrangements. Application of the brood method suggests that the vast majority of the detected sex-linked lethals were induced in spermatozoa or spermatids. The findings suggest that secondary effects rather than an immediate direct involvement of DNA account for the mutagenic action of BUdR in D. melanogaster .

An attempt to induced crossing-over in males of Drosophila melanogaster with ovarian extract.

Von zwei fruheren, sich widersprechenden Befunden wird einer gestutzt: Ovarialextrakte vonDrosophila losen in Mannchen keine «crossing-over» aus.

Progeny: sperm ratios and segregation-distorter in Drosophila melanogaster.

Progeny: sperm ratios (P/S) were determined from crosses ofSD/cn bw males ofDrosophila melanogaster with females of eight different genotypes. Thek value was about 1.0. P/S ratios of 0.88, 0.81, and 0.76, respectively, were observed from crosses with females of three genotypes, and ratios in the 0.3–0.4 range from five. These results support the suggestion ofZimmering & Fowler (1968) that P/S ratios may vary widely and depend at least in part on the genotype of the female. Morcover, since P/S ratios of 0.9 may be observed whenk is about 1.0, it follows that the vast majority of sperm stored in these females areSD.

Pulse interval as a critical parameter in the courtship song of Drosophila melanogaster

Summary o 1. Males of Drosophila melanogaster produce courtship songs which sexually stimulate the females. The songs consist of trains of single cycle pulses of sound of 3 msec length separated by intervals of 34 msec. 2. The effect on female receptivity of varying pulse length and pulse interval was tested by using simulated songs. 3. The species specific nature of the song is determined by pulse interval and not pulse length.

NON-RANDOM ASSORTMENT IN <i>SD</i> HETEROZYGOUS XYY MALES OF <i>DROSOPHILA MELANOGASTER</i>

Segregation Distorter (SD) was found to assort more frequently with the Y-chromosome in SDcn/SD+; XYY males of Drosophila melanogaster. Because gametic and zygotic selection can be eliminated as possible explanations of this non-random assortment, it is suggested that the pairing pattern in the sex chromosomes is changed when segregation distortion occurs. The hypothesis of homology between the SD region and part of the X-chromosome suggested by Hiraizumi and Nakazima (1967) could be one possible explanation.