Genetic load and effective size of natural populations ofDrosophila melanogaster in Korea

Summary The effect of 750 second chromosomes ofDrosophila melanogaster on viability was studied. 19.3% of them proved letal or semilethal (=drastics) in homozygous condition. Compared to data obtained in previous years at the same sampling site, a significant frequency decrease of drastics during the past decade could be observed. The dynamic processes taking place in the Korean wild populations ofD. melanogaster are discussed.Acknowledgment. This work was supported by a research grant from the Korean Science and Engineering Foundation.     

The effect of DDT on DNA replication in the larval salivary gland cells ofDrosophila melanogaster

Summary The inhibitory effect of DDT on the initial stage of the DNA replication process in polytene chromosomes of larval salivary gland cells ofDrosophila melanogaster was investigated and possible mechanisms for the inhibition are discussed.     

The evolutionary history ofDrosophila buzzatii. V. Differential survivorship onOpuntia betweenD. buzzatii andD. serido

Summary Survival time ofDrosophila buzzatii adults on anOpuntia (prickly pear) medium was significantly longer than that of its nearest relativeD. serido. A significant difference was also found betweenD. buzzatii adults from two experimental populations, one of them fed onOpuntia rots for more than two years and another one kept on standardDrosophila medium for the same period of time. These results suggest that adult selection may be taking place in cactiphilicDrosophila in their natural habitats and could be responsible for the niche differentiation betweenD. buzzatii andD. serido.This work has been supported by the Comisión Asesora de investigación Científica y Técnica, Spain, by funds to project 4514/79 awarded to the third author.     

Genotoxic evaluation of ten carcinogens in theDrosophila melanogaster wing spot test

To provide further background data on the wing spot somatic mutation and recombination assay, 10 selected carcinogens (acetamide, acrylamide, benzo(a)pyrene, cyclophosphamide, diethylstilbestrol, 4-nitroquinoline N-oxide, propyleneimine, safrole, thiourea, and o-toluidine) were tested in this assay. 72-h-old third-instar larvae, trans-heterozygous for 2 recessive wing cell markers:multiple wing hairs (mwh) andflare ³ (flr ³) were fed with 3 concentrations of each carcinogen during the rest of their development until pupation, and the genotoxic effects were measured as significant increases in the appearance of visible mutant hair clones on the adult wing blade. Our results show that 6 of the carcinogens tested produce significant increases in wing spot frequency, at least at one of the concentrations assayed. Benzo(a)pyrene, diethylstilbestrol, safrole and thiourea were the compounds that did not increase the incidence of mutant clones.     

Genetic basis of some morphological differences between temperate and equatorial populations ofDrosophila melanogaster

The genetic basis of three morphological traits (ovariole number, sternopleural bristle number and wing length) ofDrosophila melanogaster has been investigated in natural populations that show great differences in these traits, i. e. Bordeaux (France) and Loua (Congo). F1 and F2 crosses, and chromosome substitutions between these two populations, were analysed. Maternal and/or X chromosome effects were found for sternopleural bristle number and wing length. For all traits, significant effects from each of the three chromosomes were found, but in general only one or two chromosomes had a major effect. Moreover, in all cases significant interactions between chromosomes were observed, suggesting the existence of epistatic effects. Our results are discussed and compared to those obtained from the analysis of selected laboratory strains.     

Low allozyme and mtDNA variability in the island endemic speciesDrosophila sechelia (D. melanogaster complex)

Summary Genetic variability ofD. sechellia is investigated at both mitochondrial and nuclear levels. The results reveal the existence of a single main type of mtDNA with very few variants and a very low enzyme polymorphism. This situation is consistent with the small population size of this specialized species.     

The role of assortative mating among age-classes inDrosophila melanogaster: preliminary results

Summary A series of experiments on age-related mating success and productivity provides evidence for assortative mating among three out of four age-classes inD. melanogaster. The preferred mating does not always result in the highest productivity. Three age classes of males contribute to reproduction while only females of the youngest age-class are involved. The progeny size is more affected by the age of the females than that of males. It is assumed that these findings must have important implications for generation overlap in natural populations.     

Male non-coding RNA genes identified by comparative genomic analysis of the Drosophila genomes

This issue published a research article by Yang et al. of Peking University “Significant divergence of sex-re-lated non-coding RNA expression patterns among closely related species in Drosophila”. In a genomic     

果蝇姊妹种间亲缘关系的聚类分析

本文以聚丙烯酰胺凝胶电泳（ＰＡＧＥ）技术分析了金色果蝇复合种（Ｄｒｏｓｏｐｈｉｌａａｕｒａｒｉａｓｐｅｃｉｅｓｃｏｍｐｌｅｘ）的５个姊妹种共１７个地理种群及其它种类的５个地理种群的８种同工酶酶谱，根据其中７种酶（Ａｍｙ、Ａｏ、Ｅｓｔ、α－Ｇｐｄｈ、Ｍｄｈ、Ｍｅ、Ｔｙｒ、Ｔｏ）的条带特征按Ｆｏｒｇｕｓｏｎ及Ａｑｕａｄｏ　＆Ａｖｉｓｅ的公式分别计算遗传相似系数及遗传距离，以类平均法（ＵＰＧＭＡ）进行了聚类分析，绘制出８个种类共２２个地理种群的生化系统树，结合姊妹种间无选择杂交可能组合的结果讨论了ａｕｒａｒｉａｓｐｅｃｉｅｓｃｏｒｎｐｌｅｘ各姊妹种间的亲缘关系、种化模式及分布在日本Ｋａｍｅｔｏｋｕ岛上的Ｄ．ｔｒｉａｕｒａｒｉａ发生分化的可能性。     

红芪加工废弃物活性多糖对果蝇生育力和寿命及抗氧化能力的影响

研究红芪废弃物中提取的生物活性多糖对黑腹果蝇的生殖能力、寿命和抗氧化能力的影响.通过不同浓度的红芪多糖对黑腹果蝇的存活试验,研究了一代至四代(F1-F4)的生殖能力和寿命、雌雄个体数、抗氧化酶超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的活性和丙二醛(MDA)含量的变化.结果表明,与对照组相比,添加多糖可提高F1-F...