How many times have we heard or asked the question “Which came first, the chicken or the egg“? Science may finally have the answer and it comes from a prehistoric single-celled organism, the Chromosphaera perkinsii, found in Hawaii and studied by researchers at the University of Geneva: the egg was born first! Intuitively, we could have already thought that the egg was born first, since according to the theory of evolution, birds derive from reptiles, which already laid eggs. Furthermore, again according to evolutionary theories, a living being cannot change throughout its life, but there must always be a passage in the progenytherefore in theory, the hen should have been born already differentiated from an egg (even if it was a reptile). This recent research published in Nature, however, goes deeper and confirms the primary birth of the egg, not only with respect to the hen, but apparently also with respect to all the animals on the planet. This organism forms multicellular colonies with a mechanism very similar to that of the early stages of embryonic development and can explain how animal multicellularity can derive from evolutionary mechanisms.
How the egg was created: from a unicellular organism to a multicellular colony
The study in question was conducted at the University of Geneva and published in the journal Nature. The team of researchers carried out an investigation into a primordial unicellular organism very old, dating back to about beyond a billion years agothe Chromosphaera perkinsiiof the class of Ichthyosporians. This organism, discovered in the sediments of the seabed of shallow seas Hawaiian Islandsit is an organism autotrophthat is, capable of providing its own nourishment starting from inorganic molecules, it does not parasitize, unlike almost all other organisms belonging to its class, and is existed before all animals on earthof whom he is a close relative.
Once it reaches a specific size, this unicellular organism, despite being extremely primordial, begins to divide and produce a multicellular colony, with types of distinct cells coexisting, specifically at least two different types of cells, which will then each migrate on their own.
This dynamic, up to the formation of distinct cells, is very similar to that of the formation of one blastula, a stage in the embryonic development of an egg. The blastula is a cluster of cells resulting from a process called palintomythat is, that process which is part of the initial phases of cell division (called phases of cleavage), during which cells divide a lot but without cell growth. Then, after various processes, the differentiation into tissues will begin.
An important study to understand animal origins
The findings of researchers at the University of Geneva on Chromosphaera perkinsiisuggest that it Multicellular development is much older than previously thought previously or that has evolved into convergent way, that is, an evolutionary mechanism in which similar processes emerge independently in very different organisms. Since the formation of multicellular colonies of Chromosphaera perkinsii it exists only in this organism and not in others THEttiosporiansthe convergence option could be the most popular, but it is not a certainty. The researchers say they will focus on this aspect in future studies.
The fact remains that this organism may have programmed the future existence of eggs before they actually existed and this study lays new foundations and opens a further path to better understand animal origins.
