The process is similar to the development of the lateral line, a sensory organ in fish. The lateral line allows the animals to sense environmental conditions, such as temperature.
Scientists suspect that as ancient vertebrates emerged from the sea, they eventually lost their lateral lines as well as their ability to sense electric fields.
Today only a few species, such as sharks, sturgeons, and lampreys, have electro-sensing capabilities.
"You can imagine how valuable this system would be if you were aquatic, because water is so [electrically] conductive," said James Albert, a study co-author.
But sensing electric signals doesn't work as well on land, since air isn't a good conductor of electricity.
"When it happens [on land], it's called a lightning bolt, and you don't need special receptors to sense it," Albert said.
Dyeing to Know
Sebastian Shimeld, a zoology professor at the University of Oxford in England, is excited by the findings.
"It adds electro-sensation to the list of neural crest-derived novelties that appear to have been of fundamental importance for the early evolution of the vertebrates," said Shimeld, who was not involved in the study.
But Glenn Northcutt, a professor of neuroscience at the University of California, San Diego, is skeptical about the claim that neural crest cells give rise to electro-receptors.
More tests are needed, he said.
"It still requires a definitive experiment, where the developing neural crest cells are marked with dye, the embryo develops, and the dye clearly shows up in the electro-receptors," Northcutt said.
Dye tests are a classic method for mapping cell movements. The tests have been used to examine the origins of limbs and brain cells and the activities of cancer cells.
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