Резюме
Лавриненко А.В., Городецкая Е.В., Борони С.Э., Серга С.В., Шкляр С.Е., Козерецкая И.А. Соотношение полов как комплексный динамичный показатель в природных популяциях Drosophila melanogaster Украины.
Соотношение полов является важной характеристикой природных популяций любых раздельнополых организмов. В работе был проведен анализ соотношения полов в изосамочьих линиях из трех природных популяций D. melanogaster Украины 2012 года сбора, в которых такой анализ проводился 7 лет назад. В целом, изосамочьи линии D. melanogaster Украины 2012 года сбора характеризуются соотношением полов 1:1, и только в некоторых линиях наблюдались отклонения соотношения в сторону преобладания количества самок. Причиной такого преобладания самок в некоторых линиях является комплексное взаимодействие бактериальных агентов и генома организма-хозяина, что резко отличается от ситуации в данных популяциях 7 лет назад, в которых самки преобладали над самцами и причиной такого преобладания был бактериальный агент. А значит, соотношении полов является динамичным показателем в природных популяциях.
Ключевые слова: Drosophila melanogaster, природные популяции, соотношение полов.

Резюме
Лавриненко О.В., Городецька О.В., Бороні С.Е., Серга С.В., Шкляр С.Є., Козерецька І.О. Співвідношення статей як комплексний динамічний показник в природних популяціях Drosophila melanogaster України
Співвідношення статей є важливою характеристикою природних популяцій будь-яких раздельностатевих організмів. У роботі був проведений аналіз співвідношення статей в ізосамкових лініях з трьох природніх популяцій D. melanogaster України 2012 збору, в яких такий аналіз проводився 7 років тому. В цілому, ізосамкові лінії D. melanogaster України 2012 збору характеризуються співвідношенням статей 1:1, і лише в деяких лініях спостерігалися відхилення співвідношення в бік переважання кількості самок. Причиною такого переважання самок в деяких лініях є комплексна взаємодія бактеріальних агентів і геному організму-господаря, що різко відрізняється від ситуації в даних популяціях 7 років тому, в яких самки переважали над самцями і причиною такого переважання був бактеріальний агент. А значить, співвідношення статей є динамічним показником в природних попцляціях.
Ключові слова: Drosophila melanogaster, природні популяції, співвідношення статей.

Summary
Lavrinienko A.V., Gorodetskaya E.V., Boroni S.E, Serga S.V., Shklyar S. E., Kozeretskaya I.A. Sex ratio as a complex dynamic parameter in natural populations of  Drosophila melanogaster from Ukraine.
Sex ratio is an important characteristic of natural populations of any organisms with sexual dimorfisms. In this paper we analyzed the sex ratio in isofemale lines from three natural populations of D. melanogaster of Ukraine in 2012, the analysis of which was already made ​​7 years ago. In general, the isofemale lines of D. melanogaster of Ukraine in 2012 was characterized by a 1:1 ratio, and only some of the lines were observed to have ratio deviations with increased amount of females. The reason of such effects in those isofemale lines can be a complex interaction of bacterial agents and the genome of the host organism, this situation is quite different from the one that was 7 years ago,  in which females  predominated over males and the reason of this was the bacterial agent. This is why the sex ratio is a dynamic parameter in natural populations.
Keywords: Drosophila melanogaster, natural populations, the sex ratio.

UDC 575.17+591.557(477): 595.773.4: 575.224.4.

SEX RATIO AS A COMPLEX DYNAMIC PARAMETER IN NATURAL POPULATIONS OF  DROSOPHILA MELANOGASTER FROM UKRAINE

Lavrinienko A.V., Serga S.V., Gorodetskaya E.V., Boroni S.E,

Shklyar S. E., Kozeretskaya I.A.

Taras Shevchenko National University of Kyiv

Special place of modern genetics studies is dedicated to understand the processes occurring in natural populations of a particular organism. The most informative of these studies are investigations of natural populations of model organisms, such as Drosophila melanogaster, since biology and genetics of this organisms are observed at a reasonable level that can be adequately evaluated in the results.

Sex ratio is an important characteristic of natural populations of any dioecious organisms. The shift of this parameter can affect population size, population fitness to constantly changing environment conditions and, as a consequence, affect the evolution of species.

The aim of this work was to analyzed the sex ratio in isofemale lines from three natural populations of D. melanogaster from Ukraine sampled in 2012, which was already made 7 years ago.

Samples from natural populations of D. melanogaster were collected in three different locations of Ukraine, namely, in the town of Uman, Varva and Chornobyl Nuclear Power Plant (Chernobyl zone). Females from natural populations were transferred to the laboratory conditions by establishing isofemale lines of each population. We have been analyzing the sex ratio within five generations of cultivation in laboratory conditions.

Analysis of the sex ratio in isofemale lines within five generations of laboratory breeding showed that in general, the isofemale lines of D. melanogaster from Ukraine sampled in 2012 was characterized by a 1:1 ratio, and only some of the lines were observed to have ratio deviations with increased amount of females.  

 To determine the reason of such effect, isofemale lines with biased sex ratio were transferred to a nutrient medium with antibiotic tetracycline. Also, for further analysis we used the lines in which the number of females was close to 50 % in all five generations.

Based on these data, we assumed that the bias in sex ratio towards the predominance of females in natural populations of D. melanogaster from Ukraine sampled in 2012 is a result of a complex interaction of bacterial agents and the genome of the host organism. For example, the Drosophila genome effect was obviously observed in the lines where the bias in the sex ratio had place both on standard and tetracycline-added medium. In some lines, after adding tetracycline, the sex ratio was approached to 1:1 value, while on standart medium we observed predominance of females. In such cases we suggested bacterial nature of such deviations. The situation in these lines is similar to the one which was presented in the populations sampled in 2005 and 2006. It should be noted that there were only two lines with sex ratio 1:1, but the majority of lines on the tetracycline-added medium, demonstrated the predominance of females at least in one generation. Likely, the reasons of this phenomenon is a response of the fruit fly to the removing of microorganisms by tetracycline. However, in some lines, we have observed the sex ratio close to 1:1 both on standard and tetracycline-added medium suggesting the absence of any direct tetracycline affect.

In general, we concluded that isofemale lines of D. melanogaster from Ukraine sampled in 2012 were characterized by a 1:1 ratio, and only some of the lines had ratio deviations with increased amount of females. The reason of such effect is a complex interaction of bacterial agents and the genome of the host organism. Identifying the specific bacterial agent, which affect this parameter  requires further investigation.