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22.04.2014, 17:55 | |
Резюме Резюме Summary 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. | |
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