Sessile Organisms
Online ISSN : 1883-4701
Print ISSN : 1342-4181
ISSN-L : 1342-4181
Cellulose production and the evolution of the sessile lifestyle in ascidians
Yasunori Sasakura
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2018 Volume 35 Issue 2 Pages 21-29


The outstanding characteristics of the marine invertebrate chordates, ascidians, are a sessile adult stage and cellulose production. These characteristics are not seen in other chordate groups. Molecular studies have suggested that these two characteristics are tightly linked. Ascidians possess the gene encoding cellulose synthase in their genomes. The disruption of the cellulose synthase gene results in abnormal metamorphosis and failure in adhesion, suggesting that cellulose is necessary for starting and continuing sessile life. Ascidian cellulose synthase is suspected to have been transferred to the tunicate ancestor from a bacterial group by horizontal gene transfer. It was suggested that by this transfer, the ancestor of tunicates was given both the gene body and an epidermal enhancer from the bacterium. The simultaneous transfer of these two genetic elements is thought to have facilitated the success of the gene transfer, which enabled the ancestor to utilize cellulose for evolving sessile ascidians.

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© 2018 The Sessile Organisms Society of Japan
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