deucaryogenèse

Deucaryogenesis refers to a proposed evolutionary transition where prokaryotic organisms, lacking a membrane-bound nucleus and other organelles, transitioned into eukaryotic cells, which possess these complex structures. This hypothetical process is central to understanding the origins of life as we know it. The prevailing theory suggests that eukaryotes arose from a symbiotic relationship between different prokaryotic lineages, a concept known as endosymbiosis.

One key event in deucaryogenesis is believed to be the engulfment of an aerobic bacterium by a host archaeon. This engulfed bacterium eventually evolved into the mitochondrion, the powerhouse of the eukaryotic cell. Another significant step involved the development of the nucleus, which likely originated from infoldings of the host cell's plasma membrane, enclosing the genetic material. The acquisition of other organelles, such as chloroplasts in plant and algal lineages, also occurred through subsequent endosymbiotic events.

The exact timing and precise mechanisms of deucaryogenesis remain subjects of ongoing research and debate. Scientists investigate various lines of evidence, including genetic sequencing of modern organisms, fossil records, and comparative genomics, to piece together this ancient evolutionary puzzle. Understanding deucaryogenesis is crucial for comprehending the diversity of life on Earth and the fundamental characteristics that distinguish prokaryotic and eukaryotic cells.