A British-led study has determined how the zebrafish (Danio rerio) develops one of its four stripes of pigment cells.

   Researchers led by Robert Kelsh of the University of Bath focused on a particular zebrafish mutant known as choker, which is distinctive because one of the four stripes running down its side is missing, and it has a dark collar, or choker, around its neck.

   Dark spots and stripes in fish, amphibians and reptiles are usually caused by a type of cell known as a melanophore, which contains high quantities of the pigment melanin. 

  Using time-lapse photography, the team showed how the melanophores migrate in developing embryos of both wild-type zebrafish and the choker mutant. The researchers discovered a molecule, known as Sdf, appears to encourage melanophore cell migration in the fish.

   "Similarities between animals mean that we can take what we learn about the development of these simple models, and begin applying them to more complex systems, such as humans," said Kelsh.

   The research, which also involved scientists from the British universities of Cambridge and Sheffield, the University of Oregon in the United States and Australia's Cardiac Research Institute, appears in the journal Development.

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