The Adaptive Value of Chromosomal Inversions and Climatic Change-Studies on the Natural Populations of Drosophila subobscura from the Balkans

Abstract

Climatic change is a serious problem because it can irreversibly modify most ecosystems. Many species try to survive by adapting, through natural selection, to the new climatic conditions. In this scenario, the inversion chromosomal polymorphism of Drosophila subobscura is an excellent natural system through which to study the adaptations of organisms to climatic change. For analyzing the response of inversions to global warming, the chromosomes of annual samples (2019-2022) from a Petnica (Serbia) D. subobscura population were analyzed. These results were compared with those from other populations of this species, but belonging to different climatic regions (Avala, also in Serbia, and Font Groga, Spain). In all cases significant differences were observed, indicating that the inversion composition conferring adaptive capacity to flies in these regions was different. In Petnica, not all inversions responded in the same way to climatic variables: those located in E and U chromosomes presented more changes. Moreover, by comparing data from 2019-2022 with those from a previous sample also from Petnica (1995), it was possible to relate the changes in meteorological variables to frequency variations of 'cold', 'warm', and 'non-thermal'-adapted inversions for these years. These results allow for a better understanding of the genetic adaptations to new environmental conditions.