Neil Shubin: Tracing fins to limbs
By Hannah Hayes
Photo by Dan Dry
Everyday biological processes can explain things that seem special or mysterious about the world. What is really powerful is that our explanations can be tested by an examination of the evidence.”
Since making headlines two years ago with a surprising 375-million-year-old fossil, the evolutionary biologist Neil Shubin continues to unlock the secrets of life’s formerly blurry transition from sea to land.
The electrifying discovery of Tiktaalik roseae in the Canadian Arctic in 2004 gave Neil Shubin the evidence he had relentlessly pursued for two decades. This fossil, which revealed an amphibious creature with the gills and scales of a fish but the neck, shoulders, arms and fingers of a land-living animal, was hailed as a proverbial missing link in evolution.
At the University of Chicago lab, new information continues to unfold overturning the long-held theory that the appearance of limbs was a “great” transformation that brought sea creatures to land. Rather, Shubin and his team have found that the genetic ability to build limbs from fins existed in even the most primitive fish.
The implications are profound, wrote Shubin, the Robert R. Bensley Professor and Associate Dean for Organismal and Evolutionary Biology. “Everyday biological processes can explain things that seem special or mysterious about the living world. What is really powerful is that our explanations can be tested by an examination of the evidence.”
Shubin’s ongoing investigation of the developmental biology of limbs has made him the leading voice in the synthesis of paleontology and genome study. His work has changed the way scientists think about human development and opened up new avenues of study for paleontology. With a background in developmental biology, Shubin uses DNA to follow the evolutionary pathways of organisms. His research team’s study of gene patterns in the development of fins in paddlefish and sharks—aided with the physical evidence provided by Tiktaalik roseae—has prompted the revision of previous ideas in evolutionary theory about how limbs developed.
The University of Chicago’s departments of paleontology and ecology and evolutionary biology programs are both ranked No. 1 in the country, according to rankings by U.S. News and World Report. The Committee on Evolutionary Biology is a venerable resource for graduate students and faculty, as well.
In his new book, Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body, Shubin expands his scientific inquiries and poses some striking questions about what evolution from our ancestor the fish really means. The human body, he says, is nature’s attempt to turn a Volkswagen Beetle into a hot rod. No matter how you tweak it, the product will be far from perfect.
“Take the body plan of a fish, dress it up to be a mammal, then tweak and twist that mammal until it walks on two legs, talks, thinks, and has superfine control of its fingers—and you have a recipe for problems,” Shubin wrote in the book. “We can dress up a fish only so much without paying a price.”
What we have, says Shubin, is a body struggling to adapt—like a fish out of water.
And the result is everything from obesity to hemorrhoids. By examining a breathing apparatus that began with gills and slowly transformed into a larynx and tongue, we can begin to understand why sleep apnea occurs. A perfectly designed body would not have the mouth leading to both the trachea and the esophagus, a structure that makes it easier for us to choke on our food.
Shubin, who is also Provost of the Field Museum of Natural History in Chicago, looks at our sedentary lifestyle and traces the causes of many diseases to our watery past. He raises questions about how to better adapt our bodies for our upright lifestyle. His book has sold foreign rights to 13 countries and made bestseller lists worldwide.
Originally published on March 31, 2008.