Origins of brain cells found in 800 million-year-old creatures

A new study revealed that brain cell components began forming around 800 million years ago in shallow seas. Experts from Spain and Germany have discovered characteristics of specialised secretory cells in simple animals called placozoans.

These basic creatures have no organs and are roughly the size of a grain of sand, consisting of little more than a colony of different cell types. Placozoans once hunted microbes and browsed algae in the warm shallows of seas 800 million years ago.

Also Read |Elon Musk's Neuralink gets OK for human trial of its brain implant for paralysis patients

Add WION as a Preferred Source

Parallels between neurons and 800 million years old cells

Centre for Genomic Regulation cell biologist Sebastián Najle and colleagues discovered these so-called peptidergic cells have a number of uncannily similar traits to the cells we owe our own smarts.

"We were astounded by the parallels," exclaims Najle.

Also Read |Human brain can work even after death, scientists show in new study

"The placozoan peptidergic cells have many similarities to primitive neuronal cells, even if they aren't quite there yet. It's like looking at an evolutionary stepping stone."

After a genetic analysis was carried out, it was found that cells coordinated the tiny animal’s behaviours by releasing peptide signals much as neurons do.

The researchers identified 14 different types of peptide cells in the small marine animals. Comparing the tissues in four known placozoa species as well as with other early animals, the team found these cells even have some of the same genes as our neurons.

But there were a few differences between the two. The placozoan cells were missing specialised components that our neurons have to receive peptide signals or generate electrical signals. Instead, they use receptor proteins (GCPR) to receive the chemical messages, which are common across many animal cell types and not specific to neurons.

Also Read |NASA's Curiosity rover reaches Mars ridge to study Red Planet's watery past

The genes of the peptide-releasing cells were highly conserved in all the placozoans, but absent in other early animals like sponges and comb jellies (ctenophores).

This suggests the peptide-secreting cells may have evolved before other neuron-like cells.

The first known modern neuron arose around 650 million years ago in the common ancestor of jellyfish and the bilaterian group of animals that led to us.

"Cells are the fundamental units of life, so understanding how they come into being or change over time is key to explain the evolutionary story of life. Placozoans, ctenophores, sponges and other non-traditional model animals harbour secrets that we are only just beginning to unlock," concludes evolutionary biologist Arnau Sebé-Pedros.

(With inputs from agencies)

WATCH WION LIVE HERE

You can now write for wionews.com and be a part of the community. Share your stories and opinions with us here.