Study reveals how zebra fish get their stripes

Aug. 13 (UPI) -- Every zebra fish begins life as a transparent embryo. Almost all of them end up with stripes. Now, researchers know why.

Scientists at Ohio State University developed a mathematical model that describes the organization of the zebra fish's three types of pigment cells.

"It's amazing that you have these individual cells that can sort themselves into these reliable patterns," Alexandria Volkening, a postdoctoral fellow at Ohio State's Mathematical Biosciences Institute, said in a news release. "The cells move around on the skin to create stripes. It's like individual birds that know how to flock together and fly in formation."

The research, published this week in the journal Nature Communications, suggests the pigment cell sorting process is orchestrated by iridophores.

The cells help build redundancies into the pigment cell organization process. If one sorting mechanism fails, iridophores' conductorship ensures a backup mechanism fills in.

Only recently did scientists realize iridophores played a central role in the patterning process. Until then, scientists focused on the fish's black cells, melanophores, and yellow cells, xanthophores.

"In our mathematical model, we use what we know about the interactions of the other two cell types to explain what drives iridophore behavior," Volkening said. "We found that we could predict what iridophores would do in a way that matches up well with what biologists have observed in zebrafish."

Previous experiments showed fish without iridophores sport spots instead of stripes.

The latest research showed iridophores organize the other two cell types by changing shape. But the study also showed shape-shifting instructions could come from a several different cellular interactions. The complexity of the stripe formation process ensure layers of redundancy, making the patterning process foolproof.

"We show that the complex interactions of these cells may be important for reliable stripe formation, but also key to why zebrafish have stripes but related fish have different patterns," Volkening said.