Which came first, the chicken or the egg? Scientists think they’ve finally cracked the age-old debate

It’s the age-old riddle that has baffled scientists for hundreds of years.

But experts may have finally solved the mystery of whether the chicken or the egg came first.

Scientists from the University of Geneva say the building blocks of female reproductive cells – eggs – appeared long before chickens evolved.

They analyzed a single-celled species called Chromosphaera perkinskii that was discovered in 2017 in Hawaiian marine sediments.

The first signs of its presence on Earth date back more than a billion years ago – well before the appearance of the first animals.

Researchers have observed this species forming multicellular structures that bear striking similarities to animal embryos.

This discovery suggests that the genetic programs responsible for embryonic development – ​​the process by which a fertilized egg develops into an embryo – were present before the emergence of animal life, they said.

Nature would therefore have had the genetic tools to “create eggs” long before she “invented chickens,” they explained.

Author Omaya Dudin said: ‘Although C. perkinsii is a unicellular species, this behavior shows that multicellular coordination and differentiation processes have been present in the species long before the first animals appeared on Earth.’

Previous research shows that even hard-shelled eggs, such as those of chickens, probably only emerged 300 million years ago.

Marine Olivetta, first author of the study, said: ‘It’s fascinating: a very recently discovered species allows us to go back in time more than a billion years.’

A separate study published earlier this year suggests that the ability to lay eggs regularly – compared to other birds – made chickens so attractive to humans thousands of years ago, leading to their domestication and the chicken we know today.