A new study in the US has revealed that human eyes may be complex and irreparable, yet they are structurally like those of the freshwater apple snail, which can completely regenerate its eyes.
Assistant Professor Alice Accorsi, at the molecular and cellular biology department at the University of California, studies how these snails regrow their eyes — with the goal of eventually helping to restore vision in people with eye injuries.
In a new study published August 6 in Nature Communications and highlighted in ScienceDaily, A/Prof Accorsi shows that apple snail and human eyes share many anatomical and genetic features.
“Apple snails are an extraordinary organism,” said Accorsi. “They provide a unique opportunity to study regeneration of complex sensory organs. Before this, we were missing a system for studying full eye regeneration.”
The ScienceDaily article said her team also developed methods for editing the apple snail’s genome, which will allow them to explore the genetic and molecular mechanisms behind eye regeneration.
The golden apple snail (Pomacea canaliculata) is a freshwater snail species from South America. It’s now invasive in many places throughout the rest of the world, but A/Prof Accorsi said the same traits that made apple snails so invasive also made them a good animal to work with in the lab.
“Apple snails are resilient, their generation time is very short, and they have a lot of babies,” she said.
In addition to being easy to grow in the lab, apple snails have “camera-type” eyes –the same type as humans.
Snails have been known for their regenerative abilities for centuries – in 1766, a researcher noted that decapitated garden snails can regrow their entire heads.
However, A/Prof Accorsi is the first to leverage this feature in regenerative research.
Using a combination of dissections, microscopy and genomic analysis, her team showed that the apple snail’s eyes were anatomically and genetically similar to human eyes.
“We did a lot of work to show that many genes that participate in human eye development are also present in the snail,” she said. “After regeneration, the morphology and gene expression of the new eye is pretty much identical to the original one.”
The researchers showed that the process of regrowing the eye takes about a month and consists of several phases.
“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 A/Prof Accorsi.
“It would be very interesting to develop a behavioural 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.”
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