Scientists from the Massachusetts Institute of Technology and in other places revealed chemical fossils, which were possibly left by ancient lips in the rocks for more than 541 million years. These chemical fossils are special types of steros, which are a geologically stable form of sterols, which are found in cell membranes of complex organisms. Researchers traced these special strokes to the class of sea sponges, known as Demosponges.
The depicted representation of the temporary scale for ancient straps, highlighting key joints and their possible biogenic sources. The image is provided: Shawar and others., Doi: 10.1073/pnas.2503009122.
“We don’t know exactly how these organisms would look then, but they would absolutely live in the ocean, they would be soft bodies, and we assume that they did not have Silnesem’s skeleton,” said MIT professor Roger.
In 2009, the authors determined the first chemical fossils, which, according to the visible, came from ancient lips.
They analyzed the samples of the breed from exposure in Oman and found that they determined the amazing abundance30) Sterols – a rare shape of the steroid, which they showed, was probably obtained from ancient sea sponges.
The stages were found in the rocks that were very old and formed during the Ediacaran period (from 635 to 541 million years ago).
This period took place shortly before Cambrian, when a sudden and global explosion of complex multicellular life arose on Earth.
The opening of the team suggested that ancient sponges appeared much earlier than in most multicellular life, and, perhaps, were one of the first animals of the Earth.
However, shortly after these results were published, alternative hypotheses spun to explain C30 The origin of the strata, including that chemicals could be obtained by other groups of organisms or inanimate geological processes.
The current study confirms an earlier hypothesis that the ancient sponges left this special chemical record, since the researchers revealed a new chemical firmness in the same dokambrian rocks, which are almost certainly biological origin.
As in their previous work, they were looking for chemical fossils in the rocks, which date back to the Ediacaran period.
They acquired samples from drill nuclei and outcry in Oman, Western India and Siberia and analyzed the rocks for signatures of steros, a geologically stable form of sterols found in all eukaryotes (plants, animals and any organism with a nucleus and membrane organelles).
“You are not an eukaryot if you do not have sterols or comparable membrane lipids,” said Summons Professor.
The chemical fossil, which researchers identified in 2009, was a 30-carbon sterol.
Moreover, the team determined that the connection can be synthesized from the presence of a distinctive enzyme, which is encoded by the genome that is common to demopons.
“It is very unusual to find sterol with 30 carbon,” said Dr. Lyubna Shavar, researcher in Caltech.
In the current study, scientists focused on the chemistry of these compounds and implemented the same gene obtained from the sponge31)
When they analyzed their samples of stones for C31 STRES, they found this in amazing abundance, along with the aforementioned30 STRANS.
“These special strokes were there all the time,” said Dr. Shavar.
“It took the right questions to look for them and to understand their meaning and where where they come from.”
Researchers also received samples of modern demopons and analyzed them on C31 Sterols.
They found that, indeed, stero – biological predecessors C31 The strokes found in the rocks are present in some types of modern demopons.
Walking a step further, they chemically synthesized eight different C31 Sterols in the laboratory as reference standards for checking their chemical structures.
Then they processed molecules in such a way as to imitate how stero would change when deposited, buried and under pressure for hundreds of millions of years.
They found that only two such sterles were an accurate coincidence with form C31 The sterols that they found in ancient samples of the rock.
The presence of two and the absence of the remaining six demonstrates that these compounds were not obtained by a random non -biological process.
The results, backed up by several studies of research, strongly confirm the idea that the strokes that were found in ancient rocks were indeed produced by living organisms, and not with the help of geological processes.
Moreover, these organisms were probably the ancestors of Demospions, which to this day retained the ability to produce the same series of compounds.
“This is a combination of what is in the rock, in the sponge, and what you can do in a chemical laboratory,” said Sumpsor Professor.
“You have three supporting, interconnected lines of evidence indicating that these sponges will become one of the earliest animals on Earth.”
“In this study, we show how to authentify the biomarker, confirming that the signal really comes from life, and not pollution or non-biological chemistry,” said Dr. Shavar.
A New results were published this week in Proceedings of the National Academy of SciencesField
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Lyubna show and othersField 2025. Chemical characteristics C31 Sterols from spongy and non -proterozoic analogues of the fossil wore. PNA 22 (41): E2503009122; DOI: 10.1073/pnas.2503009122
