A fascinating species of sea slug lives for months on nothing but sunlight like a plant.
The emerald green sea slug accomplishes this by incorporating genes that come from the algae it eats into its chromosomes, Marine Biological Laboratory reported. The genes allow the creature to sustain photosynthetic processes inside of it.
This is one of the only known examples of "functional gene transfer from one multicellular species to another." The finding could help lead to breakthroughs in medical gene therapy for humans.
"Is a sea slug a good [biological model] for a human therapy? Probably not. But figuring out the mechanism of this naturally occurring gene transfer could be extremely instructive for future medical applications," said study co-author Sidney K. Pierce, an emeritus professor at University of South Florida and at University of Maryland, College Park.
To make their findings, the researchers used an advanced imaging technique to find a gene from the alga V. litoreais present on the E. chlorotica slug's chromosome. This gene generates an enzyme that allows for the function of photosynthetic "machines" called chloroplasts, which are usually only seen in plant life. Once inside the sea slug the chloroplasts continue to photosynthesize for as long as nine months, producing carbohydrates and lipids for sustenance. The finding is intriguing because the chloroplasts function in the slug much longer than they would in their original algae host.
"This paper confirms that one of several algal genes needed to repair damage to chloroplasts, and keep them functioning, is present on the slug chromosome," Pierce said. "The gene is incorporated into the slug chromosome and transmitted to the next generation of slugs." While the next generation must take up chloroplasts anew from algae, the genes to maintain the chloroplasts are already present in the slug genome, Pierce says.
The finding may also have adaptability implications because the biological mechanism shows rapid evolution in the sea slugs.
"When a successful transfer of genes between species occurs, evolution can basically happen from one generation to the next," he notes, "rather than over an evolutionary timescale of thousands of years," Pierce concluded.
The findings were published in a recent edition of the journal The Biological Bulletin.
