The study concludes that the first human diagnosed with this strain of coronavirus had, in all likelihood, visited a market in Wuhan where a large assortment of wildlife were available for purchase, including snakes, bats, farm animals, poultry, and seafood.
A detailed genetic analysis of the virus was performed, in which it was compared to any available genetic information on other viruses from across the world and the animal kingdom. This work resulted in the conclusion that this new virus first formed due to the combination of a coronavirus strain usually found in bats with another coronavirus strain of largely "unknown origin." The product of this combination was a new virus that featured a mix, or "recombination," of a viral protein that recognizes and binds to host cell receptors. This ability to recognize and bind to host cells is effectively what allows viruses to enter new hosts, leading to infection and disease.
So, while the very beginnings of 2019-nCoV appear to be linked to bats, researchers also found evidence that the coronavirus at some point made its way into snakes before ultimately reaching human patient zero. It was this aforementioned ability to recombine within the viral receptor-binding protein that likely facilitated the virus’ cross-species transmission from snakes to humans.