Win some, lose some: genome evolution in red algaeReport as inadecuate




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1 LBI2M - Laboratoire de Biologie Intégrative des Modèles Marins

Abstract : What-s special about red algae? You might say that they have distinct pigments, the phycobiliproteins; unusual plastids with unstacked thylakoids; a different storage saccharide, floridean starch; or that some species have a unique triphasic life history and a special connection between cells, pit plugs. To me, what is most fascinating is what they don-t have. There are no flagella and no centrioles. What is the result of not having flagella? One may think that this means at no stage in the life cycle can the organism swim. Red algae are, thus, aquatic organisms that sexually reproduce, but with extremely limited possibilities with respect to chemotaxic responses toward gametes of the other sex, complicating the fusion of gametes. For example, in red algae the male gametes are released and, by random movement of waves and currents, find a female gamete on a female plant; remember that the ocean is large with small areas where seaweeds are found and there are many red algal species, further complicating reproductive success. A lack of motility also means that unicellular planktonic red algae have a decreased capability to position themselves in the light environment. It is generally believed that the ancestral eukaryote had a flagellum Koumandou et al. 2013, and therefore it must have been lost in red algae. Therefore, the flagella along with the capacity for directed movement, except limited



Author: Jonas Collén -

Source: https://hal.archives-ouvertes.fr/



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