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A flatworm the size of an apple seed could provide the key to humans curing cancer or growing new limbs.

That's the tangible message from Alejandro Sánchez Alvarado, the molecular biologist lauded for his work with the worm planaria and the discovery it brought. He delivered the Henry Louis Smith Lecture at »Ê¼Ò»ªÈË Thursday evening.

And he has a larger message that sounds a bit like a mother admonishing a child who is unsuccessfully searching for a missing toy: You have to look everywhere. You have to look beyond the familiar into the unknown.

Science, he cautions, has examined only a thin sliver of life on Earth. For example, 95 percent of the earth's oceans remain unexplored.

"We have rovers on Mars," Sánchez Alvarado said, "but we only know five percent of our oceans."

Examining the Unknown

We have looked at a fragment of what is possible, he said during an interview Thursday in the college's laboratory-packed E. Craig Wall Jr. Academic Center.

The trouble is that science has extrapolated from that very small sample and presumed everything else follows basically the same rules, he said.

The worm, however, didn't. Each slice of the stem cell-packed planaria would regrow into a complete, new worm, a regenerative power beyond most other animals.

Sánchez Alvarado and colleagues announced earlier this year that they had identified the specific type of stem cell that made the regrowth possible, a key that could unlock understanding of how cancer cells spread and how tissue that normally does not regenerate could regrow.

That discovery came after four or five years of failure, Sánchez Alvarado said, years of peering into the unknown. Early on, examining the planaria did not make obvious sense, he said.

"[The planaria's] biology," he said, "was counter to everything we had studied."

Examining the unknown, experimenting and, most importantly, failing builds up what some call useless knowledge, he said. But knowledge gathered about life on Earth ultimately will reflect on human biology because of deep genetic relationships between the species. Humans share 85 percent of their genetic makeup with planaria, he said.

"This is how most revolutions in technology, in industry and in economies have arisen -- from ‘useless knowledge'," Sánchez Alvarado said. "People who started trying to figure out electricity and trying to figure out magnetism, they were not thinking about the Internet or computers or cell phones or any of this wizardry we have today. All of this arose from so-called ‘useless knowledge.' This is true of physics, chemistry and biology."

The faster a researcher fails, the faster they cast off a wrong hypothesis, he said. Science is perceived as a quest for truth but really is making things less false.

"The question," Sánchez Alvarado said, "is often more important than the answer."