[Comparative analysis of the life span in HA and BA Drosophila melanogaster]. / Sravnitel'nyi analiz prodolzhitel'nosti zhizni linii HA i BA Drozophila melanogaster.

We studied lifespan (LS) of Drosophila melanogaster strains HA and BA. The first one was generated by long-term selection for low male sexual activity and features decreased LS as well as the changes in a relatively constant index--coefficient of LS variation. The BA strain was derived from the HA strain by reverse selection and has the mean LS and coefficient of LS variation similar to those of the normal strain D-32. Analysis of the death curves of the HA strain insects does not exclude existence of a subpopulation with the normal LS within these strain. The obtained data are discussed in the context of possible involvement of mobile element transposition in animal LS control.

Prolonged negative selection of Drosophila melanogaster for a character of adaptive significance disturbs stress reactivity.

The metabolism of juvenile hormone by JH-esterase and JH-epoxide hydrolase, and octopamine by tyrosine decarboxylase were studied under normal and stress conditions in flies of two related lines of D. melanogaster. One was selected for high (HA line) and another for low (LA line) male sexual activity for more than 700 generations. It was demonstrated that prolonged selection for low male sexual activity results in considerable changes in both systems. Tyrosine decarboxylase activity in males and females of the LA line was sharply reduced as compared with those of the HA and control Canton-S lines; JH-esterase and JH-epoxide hydrolase activities were decreased in females, and not in males, of the LA line. It was demonstrated that the response of both metabolic systems to heat stress is impaired in individuals of the LA line: the system of juvenile hormone metabolism does not respond to stress, and that of octopamine metabolism is decelerated. The role of juvenile hormone metabolism in male reproductive function is discussed.

[Molecular genetic analysis of hobo mobile genetic element polymorphism in the genome of Drosophila melanogaster line subjected to long-term selection]. / Molekuliarno-geneticheskii analiz polimorfizma mobil'nogo geneticheskogo élementa hobo v genome dlitel'no selektiruemykh linii Drosophila melanogaster.

The distribution of mobile genetic element hobo was examined in Drosophila melanogaster lines HA (high male mating activity) and LA (low male mating activity) before and after their isogenization using Southern blot hybridization. The probe containing a full-size hobo copy was shown to produce polymorphic multilocus hybridization with chromosomal DNA. The polymorphism was line-specific. A comparison of hybridization patterns in isogenic and original lines showed that isogenization in dysgenic crosses resulted in the appearance of additional hobo localization sites in LA but not in HA. The hobo destabilization in the LA genome correlated with genetic instability and the ability to induce H-E hybrid dysgenesis. The results obtained are discussed in relation to the possible role of hobo in inducing genetic variability in lines with low male mating activity, which may counteract deleterious consequences of inbreeding and selection in the negative direction.

[Selection for sex behavior changes the metabolism of juvenile hormone in Drosophila melanogaster]. / Selektsiia po polovomu povedeniiu izmeniaet metbolizm iuvenil'nogo gormona u Drosophila melanogaster.

The metabolism of juvenile hormone (JH) was studied in two lines of Drosophila melanogaster selected for differences in mating behavior. The lines were tested under normal conditions and after short-term heat shock. Females of the HA line (selected for high male mating activity) were shown to exhibit a high level of JH hydrolyzing activity under normal conditions. By contrast, females of the LA line (selected for low male mating activity) and males of both lines had a low level of JH hydrolysis. Stress exposure resulted in a decrease of JH hydrolysis in females of the HA line; this effect was absent in females of the LA line and males of both lines.

[Alkaline phosphatase in Drosophila melanogaster strains differing in male mating activity and their F1 hybrids]. / Shchelochnaia fosfataza u linii Drosophila melanogaster, razlichaiushchikhsia po polovoi aktivnosti samtsov, i ikh F-gibridov.

The activity of alkaline phosphatase (AP) was studied in adults of highly active (HA) and low active (LA) Drosophila melanogaster strains and their F1 hybrids, both under normal conditions and after a heat shock (38 degrees C). Under normal conditions, the HA strain expressed a higher AP activity compared to that in the wild-type strain Canton-S and dominated in respect to this character. The AP activity showed a sexual dimorphism, as it was higher in females of both strains. Heat shock (38 degrees C) induced no alterations in the AP activity of D. melanogaster.

[Genetic effects of destabilizing selection for adaptively important traits in Drosophila melanogaster lines]. / Genetickie éffekty destabiliziruiushchego otbora pri selektsii po adaptivno vazhnym priznakam v liniiakh Drosophila melanogaster.

Related lines of Drosophila melanogaster selected for reproductive activity for more than 750 generations were studied. Results of the long-term selection experiment support D.K. Belyaev's concept of destabilizing selection. Selection for a behavioral trait (male mating activity) affected the intrinsic structure of the organism. Flies of the low-activity line (LA) exhibited numerous morphological, biochemical, and physiological alterations. Variation rate in the selected lines was accelerated; appearing mutations were often allelic and nonrandomly distributed over chromosomes. Selection was shown to mediate novel sources of variability, e.g., induction and repression of the hobo hybrid dysgenesis. In the process of selection, a genetically determined program of hobo transpositions in the genome was formed.

[Directed transpositions in the genome of the mobile hobo element in a long-term selected strain of Drosophila melanogaster]. / Napravlennye peremeshcheniia po genomu mobil'nogo élementa khobo v dlitel'no selektiruemoi linii na Drosphila melanogaster.

The object of our investigation was an inbred LA strain of Drosophila melanogaster. This strain was selected during more than 700 generations for low male mating activity and was characterized by complex abnormalities and the remarkably high level of spontaneous mutability. The last property is determined by hobo system of hybrid dysgenesis. LA strain's hobo activity potential in H-E system of hybrid dysgenesis comprise 30-40%. It may be drastically increased up to 70-80% through LA-strain chromosome isogenization in dysgenic crosses. In genomes of independent isogenic LA substrains, numerous directional transpositions of hobo element take place. In spite of it, the retention of hobo element insertion sites inherent in original LA persist. The obtained data open up a new possibilities to study the genome instability mechanisms.

[Directed character of genetic variation during long-term selection of Drosophila melanogaster strains for adaptively important characters]. / Napravlennyi kharakter geneticheskikh izmenenii pri dlitel'nom otbore linii Drosophila melanogaster po adaptivno vazhnym priznakam.

Related fly strains that were selected for differences in reproductive function for about 700 generations were studied. The low-active (LA) strain differs from other related and highly active strains of interest at a set of characters. Qualitative differences in the spectrum of viability mutations are retained in strains selected in opposite directions. Low-active strains carry a great number of deleterious mutations. Such mutations are rare in the related highly active strains. Moreover, about 50% of chromosomes in the highly active strains carry supervital mutations, which increase viability. Recombination analysis showed the presence of at least several viability mutations in each chromosome of the strains studied. Unlike highly active strains, the low-active ones are characterized by an extremely high spontaneous mutation rate. The conservation of genetic heterogeneity observed in long-term selected strains, as well as the high mutation rate, must be connected with regular changes in the spectrum of retrotransposons (MDG1, MDG3) and hobo elements characteristic of the strains studied. A special crossing system that induces a sharp increase in LA induction potential in the H-E system of hybrid dysgenesis was developed.

[Esterase-6 activity in Drosophila melanogaster strains with varying male mating activity]. / Aktivnost' ésterazy-6 liniiakh Drosophila melanogaster s raznoi polovoi aktivnost'iu samtsov.

Analysis of the stocks of Drosophila melanogaster and of interstock hybrids with different male reproductive activity revealed positive connection between this index and the activity of esterase-6 in the reproductive system: ejaculatory duct, paragonies and ejaculatory bulb. X-chromosomes and chromosome 3 participate in genetic control of interstock differences of both sexual and esterase-6 activity.

[Genotypic differences in the level of N-acetyltransferase activity in mice of inbred lines and their hybrids]. / Genotipicheskie razlichiia v urovne N-atsetiltransferaznoi aktivnosti u myshei inbrednykh linii i ikh gibridov.

There are "slow" and "rapid" acetylator phenotypes in mice according to N-acetyltransferase activity (E.C. 2.3.1.5) (N-AT). The results of direct, back- and reciprocal crosses of mice lines with rapid acetylation phenotype (C57BL/He) show monogenic autosomic control of acetylation locus (Ac) with rapid allele dominance and sex dependence upon N-AT activity in males. So, genetic polymorphism according to the Ac locus exists in mice as well as in some other animal species and in humans. The results obtained in this study demonstrated the correlation between the N-AT level in mice and their predisposition to malignant tumors as well as dependence of cyclophosphamide action on the N-AT activity upon the genotype of an individual, which suggests a certain role of the Ac locus in tumor development.

The sources of genetic variability in highly inbred long-term selected strains of Drosophila melanogaster.

A highly inbred, long-term selected for low fitness strain LA of Drosophila melanogaster possesses a significant mutational load and unusually high rates of spontaneous mutability as revealed by CyL/Pm method. Our results indicate that during cross of CyL/Pm to LA strains, destabilization of copia-like and mobile elements and induction of H-E hybrid dysgenesis take place. The role of these processes in causing considerable genetic variability of LA strain is discussed.

Concerted transpositions of mobile genetic elements coupled with fitness changes in Drosophila melanogaster.

In an inbred low-activity (LA) strain of Drosophila melanogaster with a low level of fitness and a complex of inadaptive characters, in situ hybridization reveals an invariant pattern of distribution of three copia-like elements (mdg-1, mdg-3, and copia). Rare, spontaneous, multiple transpositions of mobile elements in the LA strain were shown to be coupled with a drastic increase of fitness. A changed pattern of various types of mobile elements was also observed on selecting the LA strain for higher fitness. High-fitness strains show transpositions of mobile elements to definite chromosomal sites ("hot spots"). Concerted changes in the location of three different mobile elements were found to be coupled with an increase of fitness. The mdg-1 distribution patterns were also examined in two low-fitness strains independently selected from the high-fitness ones. Fitness decrease was accompanied by mdg-1 excision from the hot spots of their location usually detected in the high-fitness strains. The results suggest the existence of a system of adaptive transpositions of mobile elements that takes part in fitness control.

Transpositions of mobile dispersed genes in Drosophila melanogaster and fitness of stocks.

In situ hybridization with polytene chromosomes was used to demonstrate the transposition of mobile dispersed genes (mdg)-1 and 3 following the selection of flies from low reproductive activity and viability (LA stock) for high reproductive activity, viability and fitness (LA+ and HA stocks). The inbred LA stock is continuously selected for low reproductive activity and viability and maintains at least for twenty-five generations a characteristic pattern of mdg-1 distribution in 14-15 sites. Inbred LA+ and HA stocks exhibit a changed pattern of mdg-1 locations and the number of sites reaches 21-25. Parallel and independent selection for higher viability may lead to similar characteristic changes in the localization of mdg-1. In several independent experiments we observed, within one generation, a spontaneous and saltatory growth of viability and fitness in the mass-bred LA stock. In these cases new mdg-1 and mdg-3 sites reproducibly appeared to within several bands, some of them characteristic of LA+ and HA stocks. We discuss the possible role of mdg in determining the quantitative characters of individuals and their fitness.