Uner Tan Syndrome and Reverse Evolution

by Mine G.

                                           
                     Image: http://www.medicaldaily.com/uner-tan-syndrome-explain-why-five-turkish-children-walk-all-fours-294076

Have you ever thought yourself walking on all fours? Or have you ever thought this could actually be the case for some people? If your answer is "no", let me talk about one of the most strange genetic disorders in the world on this week's post; Uner Tan Syndrome.

Uner Tan Syndrome (UTS) is a genetic disorder discovered by Uner Tan, a Turkish neuroscientist and evolutionary biologist, which causes people to walk on both hands and feet. It is indicated that UTS is a disorder origins from consanguinity (the situation where blood-relatives are married and pass the similar genes to children).The case study done in 2005 with the Ulas family, who lives in rural southern Turkey, showed that 5 out of 19 children from the family walked on their feet and hands, had mental retardation, and their speech was not understandable. After the study, Uner Tan named this genetic disorder as "Uner Tan Snydrome".


Further research finds that even though it is a rare disorder, there are people who have been suffering from UTS in other regions of Turkey, Iraq, Iran and Brazil.



Tan and his colleagues postulated that UTS could be a reference of human devolution. "The idea of reverse evolution was just a flash, an ‘aha’ experience, without conscious thought, that came to me as I first saw them" says Tan in an interview on NeuroQuantology. However, scientist started questioning if the case was really the "reverse evolution". In the recent research studies, scientist analysed the walking patterns of patients with UTS and proved that the UTS patients' walking pattern was different than our ape-like ancestors, linking to biomechanical causes.


According to Plos One, walking disorder on patients with UTS is caused by one or more recessive mutations, which harms the cerebellum, and as a result, leads to lack of balance. Therefore, walking on all four is a mechanical solution for patients to keep the balance of the body.

Edited by Mine G. on 19 February 2016;

On the blog post above, I discussed the aspects of UTS and human devolution, also an article published by Liza J. Shapiro and her colleagues contrasting Uner Tan's postulation of human devolution on UTS cases.


Few days ago, I had a chance to read Uner Tan's recent article about the subject matter;


"Quadrupedal Locomotor Characteristics of Uner Tan Syndrome Cases, Healthy Humans, and Nonhuman Primates in Evolutionary Perspectives", published on December 2015.


On his article, Tan indicates that walking gait analysis was performed on UTS cases from 10 families, healthy adults, terrestrial, arboreal primates and healthy human infants, rather than representing a sample from only one family.



According to a new quantitative data presented by Uner Tan, UTS cases and terrestrial primates were walking with straight legs. However, when healthy individuals were asked to walk on their hands and feet with straight legs, the participants could not, or found it difficult to walk with straight legs on all fours. When the individuals were asked to walk on all fours with flexed legs, it is shown that the participants could perform the action easily. Healthy individuals’ gaits walking on their feet and hands had similarities with arboreal primates’ gaits.






Uner Tan’s article suggests UTS cases’ gaits are similar with terrestrial primates, whereas healthy individuals performing quadrupedal walk may be close to arboreal primates’ gait characteristics. The article also indicates that healthy humans could not imitate the walk of UTS cases based on the recent study, opposing Shapiro’s claim on her article: “… the quadrupedalism used by individuals with UTS resembles that of healthy human adults asked to walk quadrupedally.”








As Uner Tan points out on his article, “It should, however, be noted that no one is certain who our real ancestors were, which makes it impossible to be conclusive in this context.”, further explanations and studies are needed to demonstrate our real ancestors and reverse evolution.

References: Tan, U. (2015, December 10). Quadrupedal Locomotor Characteristics of Uner Tan Syndrome Cases, Healthy Humans, and Nonhuman Primates in Evolutionary Perspectives. Retrieved February 19, 2016, from https://www.webmedcentral.com/article_view/5032

References: Tarlaci, S. (2010, November 10). Reader Comments. Retrieved February 14, 2016, from http://www.neuroquantology.com/index.php/journal/comment/view/76/0/10

 Shapiro, L. J., Cole, W. G., Young, J. W., Raichlen, D. A., Robinson, S. R., & Adolph, K. E. (2014, July 16). Human Quadrupeds, Primate Quadrupedalism, and Uner Tan Syndrome. Retrieved February 14, 2016, from http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0101758 

 Robinson, E. (2014, July 21). Uner Tan Syndrome Makes Family Walk On Fours. Retrieved February 14, 2016, from http://www.medicaldaily.com/uner-tan-syndrome-explain-why-five-turkish-children-walk-all-fours-294076