- Ulas family
The Ulas family is a large
family of 19 from rural southernTurkey , five (except for another, who had died)Fact|date=October 2008 of whom walk on all fours with their feet and the palms of theirhands in what is called a "bear crawl". Their quadrupedalgait has never been reported inanatomically intact adult humans. The gait is different from theknuckle-walking quadrupedal gait ofapes . In2006 , the family was the subject of a documentary: "The Family That Walks On All Fours ".The affected
siblings have a form ofnon-progressive congenital cerebellar ataxia. The brain impairments includecerebellar hypoplasia , mildcerebral cortex atrophy and a reducedcorpus callosum . They are also mildly retarded and have problems in balancing on two legs. However, they do not show the poor coordination ofhands ,speech , andeye movements often found in cerebellar ataxia. The four sisters can doneedlework . They all share arecessive mutation onchromosome 17 p [ Turkmen S, Demirhan O, Hoffmann K, Diers A, Zimmer C, Sperling K, Mundlos S. "Cerebellar hypoplasia and quadrupedal locomotion in humans as a recessive trait mapping to chromosome 17p." J Med Genet. 2006 May;43(5):461-4. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16371500&query_hl=58&itool=pubmed_docsum] ] .Source
Uner Tan of Cukurova University Medical School inAdana, Turkey , has claimed that they show characteristics of theprimate ancestors ofHomo sapiens , before the move tobipedalism . He calls the process "backward evolution" and he named the conditionUner Tan syndrome [ Tan, Uner. "A new syndrome with quadrupedal gait, primitive speech, and severe mental retardation as a live model forhuman evolution " Int J Neurosci. 2006 Mar;116(3):361-9. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16484061&query_hl=54&itool=pubmed_docsum] ] .However,
Nicholas Humphrey ,John Skoyles , andRoger Keynes have argued that their gait is due to two rare phenomena coming together Humphrey, N., Keynes, R. & Skoyles, J. R. (2005). "Hand-walkers : five siblings who never stood up". Discussion Paper. Centre for Philosophy of Natural and Social Science, London, UK. [http://eprints.lse.ac.uk/archive/00000463/01/CPNSS2.pdf] ] . First, instead of initiallycrawling asinfants on theirknees , they started offlearning to move around with a “bear crawl” on theirfeet . Second, due to theircongenital brain impairment, they foundbalancing on twolegs difficult. Because this, theirmotor development was channeled into turning their bear crawl into a substitute for bipedality.ee also
*
Knuckle-walking
*Bipedalism
*Quadruped
*Uner Tan syndrome Notes
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