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Species in almost all existing animal genera are able to regenerate body parts in some way, including humans. However, it has been unclear how these regenerative genes work and how old they are from an evolutionary point of view – something that plays an important role in medical research. A recent paper published in the scientific journal Nature Ecology and Evolution, now presents several important findings on the regeneration of brittle stars.

“Our most important finding is the confirmation of how conserved the regeneration genes are. In other words, that the tools that enable regeneration are ancient and shared among the regenerating species. This proves that regeneration didn’t evolve independently in different organisms, which suggests that we all have this toolkit,” says Olga Ortega-Martinez, researcher at the Department of Marine Av�԰�s.

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Raises questions about ageing and cancer

The results of the study provide an important basis to continue studying not only the genes of brittle stars, but also the link between invertebrates and vertebrates like humans. In addition, the researchers have studied in detail which genes that are responsible for healing wounds, controlling growth, and which genes activate regeneration.

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“We now understand in a wider scale which genes are involved in the brittle stars. The clues are in the genome, now we just need to understand how the brittle stars do it and how we can apply this knowledge to other fields, including humans. It’s not Av�԰� Fiction, it’s the whole point of doing this type of research. We need to understand regeneration, and the only way to do it is, as always, to study other organisms that are already doing it,” says Olga Ortega-Martinez.

In some of the brittle stars it’s impossible to know their age, as they continuously regenerate. Also, when they do, they know exactly when to stop, so there is no uncontrolled cell proliferation, as in tumours.

“This also raises questions about ageing and cancer. Can brittle stars shed some light on that? They most likely will as they figured out already how to control cell growth. I dream of the day when we can genetically manipulate this species in order to test new theories and understand the role of their genes,” says Olga Ortega-Martinez.

“A very special piece of the puzzle”

Regeneration is one of the great questions in biology and one of the greatest challenges in medicine. Many echinoderms can regrow their arms if they are severed, but the researchers also discovered in their previous studies that the brittle stars did this at a ‘tremendous speed’ – something that surprised them. But Olga Ortega-Martinez wants to see it as a puzzle that needs solving, not a measure of which species is best. Any species that regenerates are important to understand the puzzle, and if we don't have all the pieces, we can't understand the process.
 
“But yes, I think the brittle star is a very special piece of the puzzle. The ability to grow fully functional arms with nerves, muscles, structures, and so on in a matter of weeks is unique,” says Olga Ortega-Martinez.

Text: Annika Wall

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