Using CRISPR, scientists have created mutant albino sea urchins

Researchers at Tsukuba University have created albino sea urchins using CRISPR and hope that this species could bring the sea urchin back to the forefront of developmental biology research. This is written by Current Biology.

Biologists have been studying sea urchins for more than 100 years, because they have transparent eggs, and their embryonic development and fertilization are easily visible. And they also live up to 200 years, which makes these animals interesting for study from the point of view of longevity and lack of aging.

However, along with their long life, they also have a long breeding cycle. The most studied species of sea urchins have a breeding period of one to two years. This is a serious limitation for studies that focus on inserting or editing genes, which are based on rapidly born offspring. As the understanding of the exact function of genes began to dominate developmental biology, sea urchins lost their popularity as a model animal.

Professor Shunsuke Yaguchi and his team at the Tsukuba Shimoda University Marine Research Center wanted to find a way to shorten the breeding cycle. They explored several species of sea urchins and changed their food and environment. Thanks to these efforts, they discovered Temnopleurus reevesii, a species with a breeding cycle of only six months.

As evidence of the research concept, scientists focused on the gene, which is responsible for producing pigment that stains sea urchins. Using CRISPR technology, they knocked out the pigment gene in T. reevesii, which usually has a deep purple color. During this procedure, albino mutants were successfully obtained, but only male sea urchins survived. Therefore, to create mutants of the first generation, the team used eggs from T. reevesii and sperm from mutant individuals. They then used first-generation females and males to produce second-generation mutants that lacked both copies of the pigment gene.

These sea urchins were albinos. But survival was pretty low. Many larvae of the albino sea urchin from the F2 generation did not withstand exposure to ultraviolet light. This suggests that pigment can help protect sea urchins from ultraviolet radiation or help in regeneration.

Having shown that gene editing is possible in this species of sea urchins, future studies may use these methods on sea urchins to develop developmental biology.