A rapid change in P-element-induced hybrid dysgenesis status in Ukrainian populations of Drosophila melanogaster.

The Drosophila melanogaster P-transposable element is an example of mobile DNA transferred horizontally and known to have spread globally over the last 50-60 years. In Drosophila, the P-element causes a syndrome known as 'P-M hybrid dysgenesis' that obstructs normal ovary development in the female progeny of susceptible populations. Despite extensive research, the stability and global population dynamics of P-M dysgenic phenotypes remain poorly understood. Here, we report a recent and rapid transition in the P-M status of D. melanogaster populations from Ukraine. We demonstrate that these populations are currently dominated by the P'-cytotype characterized by active genomic P-elements and unknown from Ukraine just two decades ago. Our results suggest a recent invasion of the P-element in Ukraine, a pattern that matches recent discoveries from Turkey.

A HIGH FREQUENCY OF HERITABLE CHANGES IN NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER IN UKRAINE.

Spontaneous mutations are thought to have a stable rate for a given species. If non-adaptive, they appear at low frequencies and are governed by drift. However, environmental factors have been reported to cause spread of non-adaptive mutations in populations, governed by mechanisms, such as genetic assimilation. In the present study, we report a simultaneous appearance of a mutant and apparently non-adaptive C2 vein in Drosophila melanogaster at higher than expected frequencies in several distant populations, which excludes the role of drift or selection as the cause of the reported mutation frequencies. We discuss explanations of the phenomenon, including the role of externalfactors, such as temperature, in the possible genetic assimilation of the trait.

TP53 codon 72 polymorphic variants (Rs1042522) frequency in the Ukrainian population. / ChASTOTA POLIMORFNYKh VARIANTIV 72 KODONU GENA TP53 (RS1042522) SERED NASELENNIa UKRAINY.

OBJECTIVE: To estimate frequencies of polymorphic variants of TP53 codon 72 in the Ukrainian population. MATERIALS AND METHODS: We determined the allele frequencies for 148 healthy people. Genotyping was performed by allele specific polymerase chain reaction. RESULTS: We identified 31 individuals (20.9 %) with Arg/Arg genotype, Arg/Pro genotype was identified for 116 indi viduals (78.4 %), whereas genotype Pro/Pro was rare and was found in one person only (0.7 %). Genotype distribu tions were not within Hardy Weinberg equilibrium (χ2 = 59,7, p < 0.0001). CONCLUSIONS: Arg and Pro allele frequencies in the population of Ukraine are 60 and 40 % respectively, which is sig nificantly differ from the frequencies described in the literature for Poland, the Czech Republic, the USA and Brazil.

[The puzzle of Wolbachia spreading out through natural populations of Drosophila melanogaster].

The endosymbiotic bacteria Wolbachia are widely spread in natural populations of arthropods all over the world. This phenomenon, according to the current views, may be due either to so called reproductive parasitism (modification of sexual reproduction) or to mutualistic interrelationships with the host organism, since the bacteria are transmitted transovarially. Wolbachia are extremely widespread in natural populations and laboratory lineages of Drosophila melanogaster though they do not cause any known modifications of this insect sexual reproduction that could influence the bacteria frequency in the populations. It is found out that Wolbachia effects on drosophila reproductive processes can only consist in low-level of cytoplasmic incompatibility within laboratory lineages; in natural drosophila populations even such an effect has not been detected. The attempts to explain the wide spread of Wolbachia among representatives of D. melanogaster through fitness increasing of infected individuals were not successful either. Data obtained thereupon are contradictive and the results are not versatile. Meanwhile, there are some incomplete data on the bacteria affecting drosophila sexual behavior, expression of certain genes, ferrum metabolism. It is shown that the bacteria enhance individual resistance to RNA-viruses that, under natural conditions, infect fruit flies rather frequently, but the mechanisms of the phenomenon remain uncertain as well as the commonness of the phenomenon itself. Thus, at the one hand, it can be stated that infection by Wolbachia leads to a rather complex effect on D. melanogaster while, at the other hand, the reasons behind the wide spread of Wolbachia in natural populations of D. melanogaster still remain unclear.

[Infection with Wolbachia does not influence crossing over in Drosophila melanogaster].

The influence of infection with endosymbiotic bacteria Wolbachia on crossingover in Drosophila melanogaster between the white and cut genes in the X chromosome was studied. Reciprocal crosses have been conducted between infected and non-infected fruit fly strains. The results showed no significant effect of Wolbachia infection on the crossingover rates in D. melanogaster between the white and cut genes in X-chromosome.