Ancient Microbes May Help Us Find Extraterrestrial Life Forms

upstart writes:

Ancient microbes may help us find extraterrestrial life forms:

The earliest living things, including bacteria and single-celled organisms called archaea, inhabited a primarily oceanic planet without an ozone layer to protect them from the sun's radiation. These microbes evolved rhodopsins-proteins with the ability to turn sunlight into energy, using them to power cellular processes.

[...] Rhodopsins are related to rods and cones in human eyes that enable us to distinguish between light and dark and see colors. They are also widely distributed among modern organisms and environments like saltern ponds, which present a rainbow of vibrant colors.

Using machine learning, the research team analyzed rhodopsin protein sequences from all over the world and tracked how they evolved over time. Then, they created a type of family tree that allowed them to reconstruct rhodopsins from 2.5 to 4 billion years ago, and the conditions that they likely faced.

"Life as we know it is as much an expression of the conditions on our planet as it is of life itself. We resurrected ancient DNA sequences of one molecule, and it allowed us to link to the biology and environment of the past," said University of Wisconsin-Madison astrobiologist and study lead Betul Kacar.

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