Walk This Way . . .
Posted by Osagie K. Obasogie November 20, 2006
Biopolitical Times
Last week’s Nova had an intriguing segment on a rural Muslim Turkish family that, strangely enough, walks on their hands and feet. What’s fascinating, however, is not simply that they are quadrupeds, but how some evolutionary geneticists are using this family to put forth theories on the genetic cause of human bipedality, or our ability to walk upright. Uner Tan, a physiology professor at Cukurova University (Turkey) argues that the family is an example of “backwards evolution due to a genetic mutation.”
This suggestion that there is a single gene responsible for humans’ upright walking has been taken up by Stefan Mundlos of the Max Planck Institute (Germany), who has claimed to have found a gene on chromosome 17 responsible for bipedalism. Without it, the theory goes, it’s difficult to walk like an Egyptian. Or, in this case, like most other Turks.
Could there be other explanations? Medical examinations show that these individuals suffer from cerebellar ataxia—a brain disease affecting coordination and balance— that is probably linked to their parents being close cousins. Five of their 19 children suffer from this condition, so genes almost certainly played a role. But acknowledging that this is a product of incest’s genetic roulette doesn’t mean it has anything to do with any so-called biped gene. And it’s an even longer shot from labeling the family evolutionary throwbacks.
What often gets lost is how the troubling attitude society often has towards issues complicated by race, disability, and poverty makes it easy to accept proffered links between genes, human behavior, and health outcomes when other environmental explanations may be more appropriate. While difficulties with balance and coordination may be resolved in industrialized areas with wheelchairs, crutches, or other aids, poor people with disabilities may resort to other creative tactics to accommodate their situations. Just because this may visually mimic a theory we have about our ancestors’ development, it doesn’t follow that there is a singular gene determining this outcome.
It’s difficult to imagine that backers of this theory would feel as comfortable comparing, for example, a Protestant English quadruped family to monkeys, apes, and less evolved humans. This thinking’s eerie similarities to phrenology—where race shaped scientists’ perception of group aptitude—suggest that science, not humans, may be most in danger of evolving backwards.
This suggestion that there is a single gene responsible for humans’ upright walking has been taken up by Stefan Mundlos of the Max Planck Institute (Germany), who has claimed to have found a gene on chromosome 17 responsible for bipedalism. Without it, the theory goes, it’s difficult to walk like an Egyptian. Or, in this case, like most other Turks.
Could there be other explanations? Medical examinations show that these individuals suffer from cerebellar ataxia—a brain disease affecting coordination and balance— that is probably linked to their parents being close cousins. Five of their 19 children suffer from this condition, so genes almost certainly played a role. But acknowledging that this is a product of incest’s genetic roulette doesn’t mean it has anything to do with any so-called biped gene. And it’s an even longer shot from labeling the family evolutionary throwbacks.
What often gets lost is how the troubling attitude society often has towards issues complicated by race, disability, and poverty makes it easy to accept proffered links between genes, human behavior, and health outcomes when other environmental explanations may be more appropriate. While difficulties with balance and coordination may be resolved in industrialized areas with wheelchairs, crutches, or other aids, poor people with disabilities may resort to other creative tactics to accommodate their situations. Just because this may visually mimic a theory we have about our ancestors’ development, it doesn’t follow that there is a singular gene determining this outcome.
It’s difficult to imagine that backers of this theory would feel as comfortable comparing, for example, a Protestant English quadruped family to monkeys, apes, and less evolved humans. This thinking’s eerie similarities to phrenology—where race shaped scientists’ perception of group aptitude—suggest that science, not humans, may be most in danger of evolving backwards.
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