TV Program Description
Original PBS Broadcast Date: November 14, 2006
An intense scientific debate has ignited around a quiet but extraordinary
family living in rural Turkey—a family with five adults who walk on all
fours. Since bipedalism has long been considered one of the defining
characteristics of modern humans, such a discovery raises fascinating questions
about genetics, society, and the evolutionary history of our species. Is this
the anthropological find of the millennium, or simply a unique medical case?
NOVA sets out to unravel the controversy and meet the individuals who have
captured the imagination of scientists around the world.
While no one knows exactly when our ancestors stood up, there are clues. One of
the most haunting is a trail of human-looking footsteps unearthed in Tanzania.
Whoever made them walked on two feet more than three million years ago. Now,
shaped over the millennia by evolution, the human body is exquisitely built for
bipedal movement—from the proportion of its limbs and spine, to its
breathtaking sense of balance. Walking, hands on the ground, is a painfully
difficult task, so much so that the U.S. Marines use it as an endurance
exercise. So why are adult members of a Turkish family walking in this way?
This program takes viewers through a fascinating examination of the leading
theories.
The family, comprising the parents and their grown children, lives in a poor
and remote area of Turkey. Five of the adult children, ranging in age from 18
to 34, walk with their feet and palms on the ground. They were first
"discovered" in 2005 by scientist Uner Tan, who created a sensation in the
popular press by characterizing the handwalkers as "genetic throwbacks."
Intrigued by Tan's theory, German geneticist Stefan Mundlos has searched for a
genetic mutation that could be connected to the emergence of bipedality. But
NOVA checks in with geneticist Sean Carroll and anthropologist Brian Richmond,
two prominent researchers who believe that to view these family members as a
kind of missing link is both deeply insulting and scientifically incorrect.
Many experts reject the idea that ancient genes can simply "switch on," causing
traits to resurface after an absence of generations, or even that any one gene
could be responsible for complex physical traits and structures they believe
involve multiple genes modified over millions of years and many speciation
events (see The Genetic Factor). By comparing a quadruped chimp skeleton to a
bipedal human skeleton, anthropologist Brian Richmond shows NOVA how the
pelvis, hip, knee, and foot had to dramatically change for our ancestors to
walk upright—changes that could not have occurred through a single
mutation (see Compare the Skeletons).
Spending time with the family in Turkey, researcher Nicholas Humphrey and
psychologist Defne Aruoba also doubt the single gene theory, believing instead
that the answer to the scientific puzzle lies in the very fabric of the
family's life. Through interviews and observation, they learn that the parents
are closely related; that fearful neighbors in their fundamentalist Islamic
community have left them socially isolated; and that the handwalkers have never
had the benefit of physical therapy—treatment that would be standard
protocol, for example, in the U.S. or Britain.
Personal interviews and footage of time spent with the family are emotional and
telling (see The Family and Me). Villagers turn a blind eye as their children
taunt the adult handwalkers. NOVA's film crew takes the family on their
first-ever visit to the ocean, a mere hour-long ride from their home. Cameras
capture their efforts to stand and walk upright when presented with equipment
they have never seen before—simple aluminum walkers. Whatever view these
individuals end up providing of our ancient past, it is clear that they are a
striking example of how people are shaped by the world around them.
Program Transcript
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