Chlamydomonas reinhardtii naturally lives in soil in humid regions where its colonies resemble a fine green carpet. When it is present in fresh water, this alga has the distinctive feature of producing two flagella, which allow it to move at top speed over a thin film of water. Why was it “chosen” by scientists? The list of genes in Chlamy is particularly interesting: it is like an evolving mosaic. Chlamy has characteristics that are particular to the plant world and the animal world. Just like plants, it produces organic matter from water (H₂0) and carbon dioxide (CO₂) in the presence of sunlight. This is photosynthesis.

On the other hand, like certain animal cells, Chlamy develops cilia: flagella that help its mobility in an aqueous environment. The proteins that compose these structures are very similar to those that can be found in the cilia of epithelium cells in the trachea, the female genital tract or in the intestines of man, for instance. Therefore, studying the motility of the flagella of this alga sheds lights on the way in which the cilia participate in the transit processes of microparticles and in movements.

A small, unassuming being such as Chlamydomonas reinhardtii can therefore help scientists to unravel the mysteries of certain complex mechanisms that govern the animal and plant kingdoms. Another of this alga’s contributions to science: there is a strong chance that thanks to its “mixed” genome, it will reveal some of the secrets surrounding the common ancestor of plants and animals.