Jeff Dean, Google's chief scientist and 30th employee, is leaving after 27 years to found Discovery Loop, a public benefit corporation using AI to automate scientific research - taking co-founders Sanjay Ghemawat, Quoc Le (Google Brain), and Oriol Vinyals (DeepMind) with him. Google is a founding investor and cloud partner, supplying compute for at least the first year, with Radical Ventures and Khosla Ventures co-leading the seed. In the same announcement, Demis Hassabis steps down as DeepMind CEO to become chairman and Alphabet chief scientist, with Koray Kavukcuoglu taking over Gemini model development. Alphabet stock fell about 4%.