The first animals evolved from their single-celled ancestors around 800 million years ago, but a new paper suggests that this leap was a lot less dramatic than scientists have assumed, because the single-celled ancestor of animals likely already had some of the mechanisms that animal cells use today to develop into different tissue types.
The researchers studied a single-celled amoeba called Capsaspora owczarzaki, which is a close relative of today's multi-celled animals. Capsaspora was originally discovered living inside a freshwater snail and the team sequenced the Capsaspora genome in an earlier project and discovered that the amoeba contained many genes that, in animals, are related to multicellular functions.