[The effect of the genotype on the expressiveness of the vestigial trait and polyteny of chromosomes in Drosophila melanogaster Meig]. / Vliianie genotipa na ékspressivnost' priznaka vestigial i stepen' politenii khromosom Drosophila melanogaster Meig.

The effects of the Bar (B) and white (w) mutations on the expressiveness of the character vestigial (vg) and the degree of polyteny of salivary gland giant chromosomes were studied in Drosophila melanogaster. Either mutation changed both the expressiveness of vestigial and the degree of chromsome polyteny. A negative association between the vg expressiveness and the degree of chromosome polyteny was revealed and proved to be stronger in females than in males. The parameters under study were shown to differ between females and males.

[Phototaxis and adaptation of the eyeless Drosophila melanogaster line]. / Fototaksis i prisposoblennost' linii eyeless Drosophila melanogaster.

An artificial selection on positive and negative phototaxis of eyeless (ey) Drosophila melanogaster line was carried out. Expression of the ey trait in imago was estimating during the selection. The fitness of the "+" and "-" selected lines was evaluated by such components as heat resistance, life span, fertility of flies. The genetic analysis of phototaxis inheritance was carried out. It was found that phototaxis selection results in changes of fertility whereas it doesn't affect other indices of fitness to environmental conditions as well as the ey expression. The main polygenic systems of phototaxis inheritance are located in chromosome 2 and chromosome 3.

[Dynamics of changes in various adaptation components in Drosophila ontogenesis]. / Dinamika izmeneniia nekotorykh komponentov prisposoblennosti v ontogeneze drosofily.

We studied the effect of parental age on expressivity of trait eyeless, fertility, heat resistance, and life span of Drosophila offspring. We found that these characteristics show different changes in the offspring of aging parents. The ontogenetic curve of changes of expressivity of the trait eyeless and fertility is similar to the curve of normal distribution. As concerns the changes in heat resistance, they are complex in nature: the offspring of "young" or "old" parents has the highest heat resistance. Age of parents in the studied range does not significantly affect the mean life span of the offspring.