Primordial soup

Look: Primitive cells could help confirm Mars once hosted life

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Life on Earth is made up of cells.

But there was a time, billions of years ago, where these complex molecular structures didn’t yet exist.

Some scientists hypothesize that more primitive protocells came before the cells we know today.

Made of lipids, these spherical clusters would have had a much simpler composition.

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And they may have been a significant building block for life elsewhere in the Solar System, too.

We don’t know exactly what a protocell would have looked like, but scientists can study how lipids might assemble into more complex forms.

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By placing lipids on surfaces that mimic ones present in the early Solar System, scientists could also work out how these materials helped protocells arise.

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Writing in the journal ChemSystemsChem, researchers explain how they exposed lipid droplets to minerals from Earth and Mars, and then watched to see how molecules would react.

Here are lipids grouping into protocells on eclogite, a mineral thought to originate in Earth’s upper mantle.

Irep Gözen

They also observed the protocells forming tubular “highways” between each other on the mineral olivine.

Irep Gözen

The team also placed lipid droplets on a sample from the Martian meteorite NWA 7533.

It was discovered in the Western Sahara Desert in 2011.

NASA via Giphy

In the early universe, pieces of Mars were ejected after cosmic impacts — and some crashed into Earth.

NWA 7533 dates back to a time when water was likely present on Mars.

Clusters of lipids formed into protocells on NWA 7533’s surface, too.

Irep Gözen

But there’s one spot in particular that protocells like to grow: inside cracks.

Lead study author Irep Gözen says it was surprising to observe that the protocells had such a preference for cracks.

“This shows that surfaces ... in many different ways could have influenced primitive cell formation.”

Irep Gözen, lead study author, to Inverse.

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And seeing them grow profoundly on Martian surfaces is an indicator that billions of years ago, extremely early biology may not have been contained to Earth.

“The findings overall support the hypothesis that life as we know it on Earth could have similarly initiated on Mars.”

Irep Gözen to Inverse.

NASA via Giphy

These models help us understand the potential evolution of life, and current missions on Mars such as Perseverance could lend more weight to these theories down the road.