Genomic analyses in Drosophila do not support the classic allopatric model of speciation.
Leeban H. Yusuf, Dominik R. Laetsch, Konrad Lohse, Michael Gordon Ritchie
The study analyzes genomic data from Drosophila species to test the allopatric speciation model, finding common gene flow and suggesting speciation often involves long-term gene flow rather than extensive allopatry.