An artist’s rendering depicts a community of primeval eukaryotic entities known as the ‘Protosterol Biota’, dwelling amidst a bacterial mat on the seafloor. Molecular fossil evidence suggests that these organisms, our most ancient known progenitors, populated the oceans between 1.6 and 1.0 billion years ago. Credit: Masterfully brought to life by TA, MidJourney 2023.
Scientists from various nations have unearthed ancient protosteroids from rocks, a sign that intricate life forms existed as far back as 1.6 billion years. These molecules provide a unique perspective on the evolution of complex life, bridging the gap between traditional fossil records and lipid fossil evidence.
The newfound traces of protosteroids were surprisingly plentiful during the Middle Ages of our planet. These age-old molecules were created during an early phase of eukaryotic complexity, pushing back the existing timeline of fossil steroids from 800 million to 1.6 billion years ago. Eukaryotes denote a group of life forms comprising all animals, plants, and algae, distinguished from bacteria due to their intricate cellular structure with a nucleus, and more elaborate molecular mechanisms.
“The key revelation from this finding extends beyond simply broadening the existing molecular timeline of eukaryotes,” notes Christian Hallmann, one of the contributing scientists from the German Research Center for Geosciences (GFZ) in Potsdam. “Considering that the last shared ancestor of all modern eukaryotes, including humans, was likely capable of producing ‘regular’ modern sterols, it’s probable that the eukaryotes responsible for these rare signatures were part of the stem of the phylogenetic tree.”
Benjamin Nettersheim, a leading author of the study, studies high-resolution elemental and molecular maps of 1.64 billion-year-old rock samples at the Geobiomolecular Imaging Laboratory at MARUM. Credit: MARUM – Center for Marine Environmental Sciences, University of Bremen; V. Diekamp
The “stem” symbolizes the ancestral lineage that ultimately gave rise to all extant branches of eukaryotes. Though its members have long since gone extinct, insights into their nature can shed light on the conditions during the evolution of complex life forms. More research is needed to assess what fraction of protosteroids might have originated from rare bacterial sources. The discovery of these new molecules not only reconciles the geologic record of traditional fossils with that of fossil lipid molecules, but also affords a rare and unparalleled glimpse into a bygone era of ancient life. The competitive downfall of stem group eukaryotes, marked by the first emergence of modern fossil steroids about 800 million years ago, might indicate one of the most impactful events in the evolution of progressively complex life.
“Almost all eukaryotes synthesize steroids, such as cholesterol, produced by humans and most other animals,” Benjamin Nettersheim of MARUM, University of Bremen adds, who co-authored the study with Jochen Brocks from the Australian National University (ANU). “Due to the potential health risks of high cholesterol levels in humans, cholesterol is often viewed negatively from a medical standpoint. However, these lipid molecules are critical components of eukaryotic cell membranes and play a vital role in various physiological functions. By seeking out fossilized steroids in ancient rocks, we can trace the progression of increasingly complex life.”
Dr. Nettersheim inserts thin sections and rock slices from 1.64 billion-year-old rocks into the 7T solariX XR FT-ICR-MS equipped with a MALDI source at the Geobiomolecular Imaging Laboratory at MAR
Table of Contents
Frequently Asked Questions (FAQs) about Protosteroid discovery
What was the significant discovery made by the multinational research team?
The team discovered ancient protosteroids in rocks, indicating the existence of complex life up to 1.6 billion years ago. This finding provides new insights into the evolution of complex life and reconciles differences between traditional and lipid fossil records.
Who were the main contributors to this study?
Key contributors to the study were Benjamin Nettersheim from MARUM, University of Bremen, Jochen Brocks from the Australian National University, and Christian Hallmann from the German Research Center for Geosciences.
How did these findings reshape our understanding of early life?
The discovery of protosteroids extends the existing fossil record of steroids beyond 800 million years and up to 1.6 billion years ago, proving that complex life existed much earlier than previously thought. These primordial molecules were likely produced by an early stage of eukaryotes, our earliest known ancestors.
What is the importance of protosteroids?
Protosteroids offer a glimpse into the world of our earliest ancestors, extending the current molecular record of eukaryotes. These molecules shed light on the nature of our early eukaryotic ancestors and the conditions surrounding the evolution of complex life.
What future research does this discovery point towards?
This discovery points towards more detailed research into the early evolution of life, particularly focusing on the conditions and evolutionary pressures that led to the development of complex eukaryotic life. The researchers will further study these primordial molecules to improve our understanding of our early ancestors.
