Diatoms are one of the most significant groups of phytoplankton. These photosynthetic eukaryotes are key organisms for monitoring marine resources and predicting climate change. They also allows a better understanding of some evolutionary mechanisms, as their genomes results from a fusion of three genomes derived from their ancestors. In addition, they have multiple applications in biotechnology: in nanotechnology for their silica, as feed in aquaculture and as a biofactory for the production of molecules of interest such as omega-3 fatty acids, as well as biofuels. However, little is known about the biology of diatoms.
The complete sequencing of Phaeodactylum tricornutum (P. tricornutum) genome gives insights to expand our knowledge of the biology of diatoms. In addition, knowledge about P. tricornutum genes will promote the use of this organism as a potential cell for expressing the genes of other brown algae of interest to the industry.
Life cycle: one division per day.
Possible cycle synchronization.
Sexual reproduction never observed in culture.
Diatoms have an essentially diplophasic life cycle. Diploid cells multiply by mitosis for several months or years. However, at each cell division, one of the two daughter diatoms is smaller than the initial diatom, while the other daughter is about the same size. Thus, during successive divisions, smaller diatoms appear and one of the lineages of descendants decreases in size with each generation. This decrease on size does not continue indefinitely: below a definite threshold (30% of the initial size), these cells start meiosis and produce gametes. The gamete fusion zygote (auxospore) grows to the maximum size specific to the species or population.
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