An organism discovered near Hawaii is intriguing researchers. Its behavior could significantly alter our understanding of the origins of multicellular life on Earth.
Chromosphaera perkinsii, a unicellular algae discovered in 2017, exhibits unusual behavior. The cells form multicellular colonies, reminiscent of the earliest stages of animal embryonic development. These colonies display an unexpected organization: the cells divide without growing, coordinating to adopt three-dimensional shapes. This structure resembles that of modern animal embryos.
This species, which emerged over a billion years ago, predates the arrival of animals. According to scientists from the University of Geneva, this phenomenon indicates ancient origins for embryonic mechanisms.
Genetic analysis, conducted in collaboration with the Bigelow Laboratory for Ocean Sciences, reveals striking similarities between the processes in
C. perkinsii and animal embryos. Key genes for multicellular development could thus have been present for billions of years.
This discovery raises fundamental questions. Could embryonic genetic programs have existed before animals? Or did these algae develop similar mechanisms independently?
Omaya Dudin, professor at the University of Geneva, believes that the study of
C. perkinsii offers a window into the transition between unicellular and multicellular life. This species could be a living relic of a critical evolutionary stage. For Marine Olivetta, the lead author of the study, this research could also shed light on 600-million-year-old fossils. These mysterious embryonic forms might play into a much older evolutionary story.
Thus, the egg — both symbolic and real — might have come before the chicken in the evolutionary record.
What is embryogenesis and why is it crucial for understanding evolution?
Embryogenesis is the biological process by which a complex multicellular organism forms from a single cell called a zygote. This mechanism relies on precise stages of cell division, differentiation, and tissue organization.
In animals, embryogenesis follows similar patterns, suggesting a common evolutionary origin. Recent studies indicate that traces of this process may have existed long before the appearance of animals, in unicellular organisms.
Understanding embryogenesis means exploring the foundations of multicellular life. This mechanism reveals how complex beings emerged from unicellular ancestors, paving the way for discoveries about our deep origins.
Author of the article: Cédric DEPOND