Rate of change for the thermal adapted inversions in Drosophila subobscura

Abstract

The changes of chromosomal inversion polymorphism composition of Drosophila subobscura in samples from Apatin (Serbia) were studied in a 24-years interval (1994-2018). The variation was significant for all autosomes and directional, increasing the inversions considered as 'warm', whereas those reported as 'cold' decreased. Furthermore, the Chromosomal Thermal Index (CTI), which allows studying the thermal adaptation of the whole karyotype increased significantly in that period of time. These results were in agreement with the indicators of global warming in Apatin: a trend to increase of the mean, maximum and minimum (this latter even significant) temperatures, and an erratic pattern of rainfall (also usual in global warming). The deviations from the Wright-Fisher model of genetic drift were used to consider the possible effect of migration or selection as evolutionary factors responsible for the change in inversion frequencies. To quantify approximately the rate of change in the frequencies, for each kind of inversions ('cold', 'warm' and 'non-thermal adapted'), the difference in frequency between the Apatin samples obtained in 1994 and 2018 was computed and then it was divided by the number of years elapsed. This rate was always higher (from twice as many as thirty times more depending on the autosome) for thermal adapted inversions ('cold' or 'warm') than the 'non-thermal' adapted. From this study, it could be concluded that the chromosomal inversions of D. subobscura could change (in composition and frequencies) in a predictable direction and a rather 'rapid' rhythm to adapt to the global warming scenario.

Study of drosophila kinship from three regions in East Java, Indonesia

“…In population genetics, gene flow is the transfer of alleles or genes from one population to another [16]. Migration into or out of a population is responsible for changes in allele frequencies [17]. Migration can also lead to adding new genetic variants to the established genes of a particular species or population [13].…”

“…This result can happen due to the migration of Drosophila from Malang or Pasuruan Regency through the transportation of agricultural products. Then, the Drosophila settled and adapted to Mojokerto Regency [17]. Another external factor that influences Drosophila relationships is differences in height.…”