The only animal that performs photosynthesis

A study of the University of South Florida and the University of Maryland, College Park (USA) has discovered how it is possible that a bright green sea slug can live as a plant, feeding only sunlight. The paper has been published in The Biological Bulletin.

The slug in question is Elysia chlorotic, it resembles that of a leaf of a vegetable, it measures only six centimeters and its natural habitat are the coasts from Nova Scotia to the south of florida.

It feeds on an algae called Vaucheria litorea from which the slug has decided to "borrow" its chloroplasts to carry out photosynthesis.

To arrive at this certainty, the researchers discovered that the slug had learned to digest the alga without damaging the indispensable chloroplasts (integrating them in its digestive cells), which transform the sunlight into food, as it has algae genes essential for maintaining In good condition the chloroplasts of this.

This is the first case of functional gene transfer from one multicellular species to another (what is known as horizontal gene transfer), turning this small slug into the first and only animal capable of performing the process of photosynthesis.

"This work confirms that one of the kelp genes needed to repair damage in chloroplasts and keep them functioning, is present on the algae chromosome. The gene is incorporated in the chromosome of the slug and is transmitted to the next generation ".

Offspring only have to 'steal' the chloroplasts from the algae, since the genes for keeping the chloroplasts are already present in the slug genome. It is impossible for the genes of an algae to work within an animal cell. And yet, here they do, clarifies Sidney K. Pierce, co-author of the study.