Look anywhere in our DNA and our evolutionary past is never far away.
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| Human displaying a chimp like midtarsal break |
Jeremy DeSilva and Simone Gill asked a selection of 400 adult people to walk barefoot around the Boston museum of Science while they filmed their feet and took readings on special pressure plates. They found that a selection of people instead of having a rigid mid foot, they actually had some flexibility that allowed them to bend in the middle. (Also known as a midtarsal break.)
So what? Well originally it is believed that humans developed a significant rigidity in the foot along the same time that we stopped dwelling in trees. While everyone has the bone structure and ability to bend in the middle of our foot, we evolved stiff ligaments to prevent this from happening. Looking at some of the volunteers, they instead maintained a bend and maintained a footprint that was remarkably similar in pressure points to our ape ancestors.
Of course some people argue that this isn't necessarily a throwback to our old evolution at all.
A representative at REPP (Researching Extant Pleistocene People) instead argues that foot flexibility isn't necessarily as simple as comparing us to apes and that viewing this as an evolutionary throwback is simplistic:
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| Beast's feet concept art for X Men First Class |
"This video is the perfect example of someone reading the abstract and not the DeSilva study (not published) in its entirety. No non-divergent toed critter in history has a mid-foot flex other than humans. The flex in lower primates is nothing other than tarsal to phalange joints. The cuneiforms in divergent toed critters are under the tibia and fibula and they do not "flex" where the cuneiforms meet the metatarsals--i.e. like your wrist or primate ankles. In fact, there is an extreme set of tendons and muscles that attach from the lower knee down to the top of the arch to strengthen that area. This allows for a stiff foot and increased running speed--as observed in every mammal on the planet. In DeSilva's study, in his conclusion, he stated that the "1" in all cases gave and "appearance" of a joint and was the result of either inactive obesity or a degenerative disease hereditarily. If an evo-model were the case, then a mid-tarsal flex would bend "sole-side-down" in a grasping motion and not backwards to lower primates; alas, that argument is moot do to lower primates not even having this joint in the first place."
Whether you believe that this midtarsal break is significant or not, it is not the first of the many evolutionary throwbacks that still lurk in human genes.
Some humans are born with vestigial tails, some with fur, some grow wisdom teeth and we all hold the largely defunct appendix inside of us. Humans are an open evolutionary book and sometimes our bodies like to surprise us.
Sources
-New Scientist.com
-Youtube Comment by REPP
- Why some humans are born with tails: Youtube
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