Which came first, the chicken or the egg? An ancient "witness" has provided scientists with a definitive answer.

The famous logical paradox seemed unsolvable: on one hand, an egg is needed for a chicken to be born, while on the other hand, a chicken is necessary for an egg to appear. This creates a closed loop. However, researchers at the University of Geneva have managed to resolve this sophism.

The scientists discovered a valuable "witness" – a single-celled organism of the species Chromosphaera perkinskii, found in 2017 in marine deposits in Hawaii. Its age is estimated to be one billion years – long before the first animals emerged, whose traces appear in the geological record approximately 600 million years ago.

The authors of the article, published in the prestigious journal Nature, found that this species formed structures that strikingly resemble animal embryos. This discovery indicates that the genetic program for embryonic development (in this process, the egg – a fertilized egg cell – develops into an embryo) existed even before the emergence of animals. Therefore, claims Marine Olivetta, a researcher at the Department of Biochemistry at the University of Geneva, nature had the genetic tools to "create eggs" long before evolution "invented chickens."