About this Research Topic
How simple biological systems can be? The study of the early evolution of life on Earth might provide an answer to the above question. Parsimony suggests that primitive cells were simpler than the simplest cells living today. However, these early cells were lost forever and we can only make educated guesses on their nature. Research on the nature of early cells includes theoretical work, in vitro experiments as well as in silico comparative genomics to construct plausible historical narratives.
Extant biodiversity can inform us about life at its minimum. The descendants of these early cells diversified over the eons into the myriad different species we know today. Present day organisms are more complex than those very early life forms. However, by associating symbiotically to other organisms, some lineages of prokaryotes evolved highly reduced genomes. Some of these prokaryotes contain surprisingly few genes. Although some of these organisms may have lost the status of a cell to become something similar to organelles, (i.e., symbionelles) they collectively inform us on the minimal gene complements required for cells to adapt to the diverse environments on which they evolved.
Furthermore, synthetic biology attempts to construct living systems starting from basic components, the so-called bottom-up approach, and is a complementary top-down approach, whereby simplified versions of cells are engineered by knocking out genes, will certainly improve our understanding of the inner working of cells.
To deepen our knowledge on the minimal and sufficient functions for life, in this Research Topic, we are interested in bringing together hypothesis about the evolution of early cells, present day knowledge about the biology of prokaryotes with reduced genomes, and the state of the art of synthetic biology attempts to construct and understand minimal cells. In particular, we encourage new ideas that can boost new and unexplored research avenues. We welcome researchers from these different areas to contribute to this Research Topic in an attempt to better understand the essentials for life.
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