Google's AI leadership has gone through a reshuffle, with the company's chief scientist stepping down.

Alongside Jeff Dean's departure, DeepMind co-founder and CEO Demis Hassabis is stepping back to become chairman of the AI division. At the same time, he will replace Dean as chief scientist.

After 27 years at the tech giant, Dean said that he was leaving to found Discovery Loop, a public benefit corporation focused on automating machine learning, science, and engineering discoveries. Google will take a stake in the business.

He will be joined by fellow Google veteran Sanjay Ghemawat, who was instrumental to the development of products like TensorFlow, Bigtable, and Spanner.

Also joining Discovery Loop is Oriol Vinyals, VP of research & deep learning lead at Google DeepMind and Gemini co-lead. Rounding out the cofounders is Quoc Le, Google DeepMind fellow and a founding member of the Google Brain project.

DeepMind head Demis Hassabis will take Dean's role as chief scientist, and become chairman of DeepMind. He said that he will focus on developing Artificial General Intelligence (AGI), as well as retain his position as CEO of AI drug discovery subsidiary Isomorphic Labs.

Replacing Hassabis as the lead of DeepMind is Koray Kavukcuoglu, current DeepMind CTO and Google chief AI architect.

Shares in Alphabet fell five percent on the news.