In a major revelation for the long-standing chicken-or-egg debate, researchers have discovered that nature was serving up “eggs” long before chickens—or even animals—came into the picture. The mystery has been cracked, but in doing so, it has opened an entirely new chapter in the story of life’s origins.
Enter Chromosphaera perkinsii, a billion-year-old unicellular organism found in marine sediments near Hawaii. This tiny protist threw evolutionary biologists for a loop by organizing itself into multicellular structures that closely resemble the earliest stages of animal embryos.
A sequence of images shows Chromosphaera perkinsii forming a colony, much like early cell division you might see in animal embryos. But this is a single-celled organism doing something extraordinary.
Researchers from the University of Geneva (UNIGE), led by Omaya Dudin, have spent years studying C. perkinsii, and the results are truly remarkable. Unlike most single-celled organisms, C. perkinsii can coordinate its cell division without growing larger. Instead, it forms colonies that mimic the early steps of animal embryonic development.
As Dudin explains, “Although C. perkinsii is a unicellular species, this behavior shows that multicellular coordination and differentiation processes are already present in the species, well before the first animals appeared on Earth.”
Even more surprising? When scientists examined the genetic activity within these colonies, they found it strikingly similar to what happens in modern animal embryos. The processes that enable embryos to grow from a single cell into a multicellular organism—key to the development of animals—were apparently already in the evolutionary toolkit long before animals even existed.
The study, published in Nature, suggests that multicellularity may have evolved multiple times in different lineages, meaning the transition from single-celled organisms to complex creatures may have been more chaotic and less linear than previously thought.
Marine Olivetta, one of the researchers, says, “It’s fascinating that a species discovered very recently allows us to go back in time more than a billion years.”
This discovery could also bring new light to the debate over ancient 600-million-year-old fossils that resemble embryos. Are they early animals or organisms like C. perkinsii? Regardless, this small protist shows that nature was experimenting with egg-like developmental strategies long before any animal, be it a chicken or even a jellyfish, existed.
For those still rooting for the chicken, it’s time to concede. The egg wins. While these ancient “eggs” didn’t have shells or yolks, they laid the groundwork for the evolutionary developments that would eventually lead to the familiar breakfast staple we know today.
Still unsure? Neil deGrasse Tyson offers an evolutionary perspective, asserting that the egg came first—it was just laid by a bird that wasn’t quite a chicken.
Discoveries like this remind us how much remains unknown about life’s origins. If a billion-year-old protist can answer one of our oldest questions, imagine what else nature is hiding in its archives. But one thing is clear: we now have our answer. The egg came first, and it’s been waiting for us to catch up for over a billion years.
With that puzzle solved, it’s time to find something new to debate. Perhaps the classic “if a tree falls in a forest” question will be the next to crack.