'Filipchenko was Dobzhansky’s formal and informal research supervisor, and a true friend, despite a twenty-year age difference. He invited Dobzhansky to carry out his genetical research on Drosophila in Leningrad, under very favorable conditions for that time, and later arranged for Dobzhansky to work in Thomas Hunt Morgan’s laboratory in the US (Konashev 2008.) Some of his ideas were also foundational in Dobzhansky’s search for solutions to the problem of species and speciation.'

https://link.springer.com/article/10.1007/s10739-023-09709-9