Get ready to travel back in time over a billion years ago, as paleontologists provide a fascinating look into ancient life based on chemical traces in rocks and the genetics of modern animals. The groundbreaking research, published in Nature Communications on Dec. 1, uncovers the geological and genetic factors that led to a significant shift in how animals consume their food.
Meet David Gold, an associate professor in the Department of Earth and Planetary Sciences at the University of California, Davis, who is leading the way in the new field of molecular paleontology. Gold is bridging the gap between geology and biology to unravel the mysteries of life’s evolution using cutting-edge technology and innovative research methods.
Did you know that lipids can endure in rocks for hundreds of millions of years? Scientists have discovered traces of sterol lipids, derived from cell membranes, in ancient rocks dating back as far as 1.6 billion years. It’s fascinating to learn that C27 sterols, which are used by most animals today, have been found in rocks that are 850 million years old, while traces of C28 and C29 sterols, typically used by fungi and plants, appeared about 200 million years later. These findings coincide with a time of increasing diversity in life and the emergence of the first fungi and green algae.
Unlocking the secrets of ancient animals and plants can be challenging without physical fossils. However, a genetic analysis by Gold and colleagues is shining a new light on this age-old mystery.
But that’s not all — the study also delves into an intriguing discovery about animal feeding habits. It turns out that most animals rely on plants or fungi to obtain phytosterols, as they cannot produce them on their own. This revelation led to the identification of a specific gene in segmented worms, known as smt, which is essential for producing longer-chain sterols.
Unraveling the mysteries of life in ancient oceans, the study proposes that the rise of algae in the world’s oceans prompted animals to abandon phytosterol production and rely on this newfound food source. If this interpretation is correct, then the history of the smt gene represents a significant shift in animal feeding strategies early in their evolution.
The paper’s co-authors include Tessa Brunoir, Chris Mulligan, Ainara Sistiaga from the University of Copenhagen, K.M. Vuu, and Patrick Shih from the Joint Bioenergy Institute at Lawrence Berkeley National Laboratory.