Unexpected long-term changes in chromosome inversion frequencies in a Neotropical Drosophila species

Several long-term studies on Drosophila chromosome inversion polymorphisms have shown that inversions can be a valuable tool to monitor rapid genetic shifts with climate change. However, so far, no study has assessed the effects of climate change in populations of Neotropical Drosophila species. After more than 2 decades, new samples were collected from the Parque Nacional do Itatiaia, Rio de Janeiro, to assess any changes in inversion frequencies and to detect possible global warming effects on the inversion polymorphism of the second chromosome of D. mediopunctata. Our results show unexpected simultaneous changes in inversion frequencies associated with climate change. Perhaps climatic variables other than temperature underlying the process caused such change, although potential genetic drift effects or demographic factors cannot be excluded. Further studies assessing population genetic structure may help clarify the changes observed.