Regeneration is in the eye of the golden apple snail — literally. A study in the journal Nature Communications looks at the golden apple snail's regenerative properties, specifically in its eyes. Like humans, these snails have camera-type eyes, and understanding how they regenerate could lead to advanced medical treatments for humans with eye injuries.
It might seem odd that we humans have similar eyes to snails, but this ocular connection is driving Alice Accorsi, assistant professor of molecular and cellular biology at the University of California, Davis, to study possible eye regeneration.
“Apple snails are an extraordinary organism,” Accorsi said in a press release. “They provide a unique opportunity to study regeneration of complex sensory organs. Before this, we were missing a system for studying full eye regeneration.”
Along with regeneration, for this study, Accorsi and her team also worked on ways to edit the apple snail’s genome. This will help the research team understand how genes and molecular mechanisms assist in eye regeneration.
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Rapid Snail Reproduction
For the study, Accorsi and her team selected the golden apple snail — Pomacea canaliculata — because of its camera-type eyes. Originally found in freshwater areas of South America, the golden apple snail has become rather invasive and is now frequently found throughout the rest of the world, thanks to its rapid reproductive rate.
This feature also contributed to why it was an ideal specimen for this study.
“Apple snails are resilient, their generation time is very short, and they have a lot of babies,” Accorsi said in a press release.
Snail Eye Regeneration
To see how snail eyes regenerated, the research team would amputate an eye and observe the regrowth process. Over about a one-month period, the team noted that in order to reach full regeneration, the wound would first need to heal completely, which only took about 24 hours.
The team then observed as specialized cells began to reform parts of the eye, including the lens and the retina. This process took place over about a week and a half.
By the 15 day mark, all of the eye’s structures were present, including the optic nerve. However, it took a few more weeks before everything was completely regenerated.
“We still don't have conclusive evidence that they can see images, but anatomically, they have all the components that are needed to form an image,” said Accorsi in a press release. “It would be very interesting to develop a behavioral assay to show that the snails can process stimuli using their new eyes in the same way as they were doing with their original eyes. That’s something we’re working on.”
CRISPR and Snail Genes
During their experiment, the research team was also observing which genes became active during the regeneration process. They noted that the genes became active immediately after amputation and that about 9,000 genes were expressed at different rates, compared to a normal snail eye.
After the whole regeneration process — about 28 days — the snail still expressed 1,175 genes differently, indicating that though it was fully healed on the outside, the researchers still weren’t sure how functional the new eye was. Further research is still needed.
Accorsi and team also developed a way to use CRISPR to edit the snails' genes, which they tested on apple snail embryos. The team identified a gene called pax6 — a gene present in humans, mice, and fruit flies — as essential for eye development.
“The idea is that we mutate specific genes and then see what effect it has on the animal, which can help us understand the function of different parts of the genome,” said Accorsi in a press release. “If we find a set of genes that are important for eye regeneration, and these genes are also present in vertebrates, in theory, we could activate them to enable eye regeneration in humans.”
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Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Nature Communications. A genetically tractable non-vertebrate system to study complete camera-type eye regeneration
A graduate of UW-Whitewater, Monica Cull wrote for several organizations, including one that focused on bees and the natural world, before coming to Discover Magazine. Her current work also appears on her travel blog and Common State Magazine. Her love of science came from watching PBS shows as a kid with her mom and spending too much time binging Doctor Who.
