Modes of variation in alcohol dehydrogenase inDrosophila melanogaster

Zusammenfassung Neben zwei elektrophoretisch verschiedenen Varianten derDrosophila-Alkoholdehydrogenase kommen innerhalb dieser Varianten weitere Variationen vor, die sich in ihrer spezifischen Aktivität und Temperaturempfindlichkeit unterscheiden. Es wird daraus geschlossen, dass der Grad des Polymorphismus von Populationen grösser sei, als aufgrund elektrophoretischer Untersuchungen geschätzt wird.     

Genetic variation in natural populations: Morphological traits inDrosophila melanogaster

Summary In a wild population ofDrosophila melanogaster located near Madrid (Spain), it has been found that the frequency of morphological mutant phenotypes is 0.36 per captured female. The study of these females shows that they carry 3.6 recessive mutants in heterozygous condition per female. The genetic variability found is higher than the frequencies observed by other authors in other natural populations.I thank Dr F.J. Ayala for useful discussions and help in preparing the English text.     

Unstable genetic system inDrosophila melanogaster: I. Instability at theCinnabar locus

Summary A mutant strain containing acinnabar allele (cn ^rbr ,rojo brillante) is reported, that produces wild-type revertants at thecinnabar (cn) locus. Incn ^rbr /cn heterozygotes the rate of mutation is highly increased. The presence of a mutator agent acting premeiotically is indicated.D.L. Lindsley and E.H. Grell, Genetic variations ofDrosophila melanogaster. Carnegie Institution of Washington, Washington, 1968; Publication No. 627.     

Selection at the Adh locus inDrosophila melanogaster: Adult survivorship-mortality in response to ethanol

Summary Functionally significant biochemical properties of the naturally occurring electrophoretic variants at the Adh locus (ADH^fast and ADH^Slow) are correlated with the adult flies' ability to utilize and survive in an ethanol environment. The results are consistent with the idea that an environmentally dependent form of balancing selection is responsible, at least in part, for the maintenance of the polymorphism at this locus.Acknowledgment. This work was supported by NSF grant DEB 7815466 to J.M.     

Effect of ethanol and isopropanol on the activity of alcohol dehydrogenase,viability and life-span inDrosophila melanogaster andDrosophila funebris

Summary The effects caused by the addition of 2 alcohols to the culture medium of 2 species ofDrosophila, D. melanogaster andD. funebris, are compared. Ethanol at 1% concentration causes slight and tolerable changes in both species. 1% isopropanol is lethal in 1 species and causes drastic changes in the other.The author acknowledge Dr A. Prevost for continuous support and E. Juan and Ll. Serra for their helpful suggestions.     

A correlation between the ability to withstand high temperatures and radioresistance inDrosophila melanogaster

Résumé Dans une étude sur 18 races deD. melanogaster une corrélation a été trouvée entre les facultés de résistance aux températures élevées et à l'irradiation du Co⁶⁰.     

A thymidine-induced sex-linked,sex-limited temperature-sensitive lethal and the significance of modifier genes inDrosophila melanogaster

Zusammenfassung BeiDrosophila melanogaster wurde ein temperaturabhängiger Letalfaktor gefunden. Die Temperaturabhängigkeit der Manifestation wird mit dem Vorhandensein von Modifikationsgenen erklärt.     

Abnormalities of the eye pigments (pteridins and ommochromes) induced inDrosophila melanogaster by the inhibitor of xanthine dehydrogenase 4-hydroxypyrazolo (3,4 d) pyrimidine

Riassunto Quando ceppi dei mutantise ecl diD. melanogaster sono fatti crescere su terreni contenenti l'inibitore della xantino-deidrogenasi 4-idrossipirazolo (3,4 d) pirimidina, si osserva una perdita parziale dei pigmenti dell'occhio: tale perdita riguarda non soltanto i pigmenti pteridinici rossi (drosopterine), fenomeno questo già descritto, bensì anche i pigmenti pteridinici gialli (sepiapterine) nonchè i pigmenti ommocromici dell'occhio.

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This research was supported by the Consiglio Nazionale delle Ricerche, Rome (Italy).     

A duplication involving the esterase 6 locus in a wild population ofDrosophila melanogaster

Summary A possible duplication of the esterase 6 locus inD. melanogaster is reported. Recombination between the duplicated loci is about 30%.     

Analysis of the relationship between age of larvae at mutagen treatment and frequency and size of spots in the wing somatic mutation and recombination test inDrosophila melanogaster

The relationship between the induction of mutant clones and the time of mutagen treatment was studied in the somatic mutation and recombination test (SMART) in wing cells ofDrosophila melanogaster. Larvae trans-heterozygous for the recessive marker mutations multiple wing hairs (mwh) and flare (flr) were produced. Batches of these larvae were then treated with mutagen at different ages spanning all three larval instars. Methyl methanesulfonate was fed acutely for 2 h by immersing the larvae in a solution of the mutagen mixed with powdered cellulose. Wings of the surviving adult flies were mounted and scored for the presence of spots. The frequency and size of single and twin spots were recorded separately. Twin spots are produced exclusively by mitotic recombination, whereas single spots can results from various types of mutational and exchange events. There exists a clear correlation between time of induction and frequency as well as size of the single spots. In young larvae only few but very large spots are induced, whereas in older larvae the frequencies are considerably increased but the sizes are smaller. The twin spots show a different relationship. Practically no twin spots are found in very young and in very old larvae. The results demonstrate that in the wing spot test the optimal age of the larvae for mutagen treatment is 72 h.