THE VII UKRAINIAN ANTARTIC EXPEDITION TRANSATLANTIC JOURNEY IMPACT ON THE DROSOPHILA MELANOGASTER CROSSING OVER
The processes of adaptation and, fimaley survival of species in a changeable environment largely depend on its fitness and plasticity. Crossing over, or homologous recombination, is one of the mechanisms providing biological species with the vital variability. The mechanisms of recombination are practically universal and characteristic of diverse taxa. However, recombination frequency is known to be substantially depends’ on the various factors. The rapid changes of latitudinal (geomagnetic field inclination and intensity) and climatic factors during the transequatorial passage make such journey unique for the genetic experiment. In this study we have made an attempt to investigate the effect of latitude and climatic factors on recombination in the sex chromosomes of Drosophila melanogaster based on the data obtained during the transequatorial passage as a part of the VII Ukrainian Antarctic expedition. Effectively, such a systems was assumed to elicit the processes that might take place in the biological systems during sudden changes in the environment (abrupt climate changes, ecological catastrophes, extreme living conditions, etc). Fly crosses were obtained during two transequatorial marine journeys: in winter (outbound from Sevastopol for Ushuaia) and in spring (Ushuaia-Sevastopol) in 2002. We have measured recombination frequency between the genes white (w: 1-1.5) and cut (ct: 1-20.0). Concurrent control experiments were performed at Taras Shevchenko National University of Kyiv. In spite of the putative sensitivity of homologous recombination of the external factors, we have found out no significant differences in recombination frequencies between the control and expedition experiments. In spring, we have even observed a slight decrease in recombination frequency between the genes white and cut, both in the control and expedition groups. These results do not resolve well with the reputed high sensitivity of the applied test to external influences. Further research is necessary to clarify the observed stability of recombination frequency.