Phenotype L of arm folding

The manner in which a person folds arms is one of the clearest dynamic morphological characteristics by which each person can be assigned to one of two alternative phenotypes. Once adopted, manner of arms folding across the chest does not change throughout the lifetime and persons easily give up the unusual folding position, most commonly at the first attempt. It has been shown that the phenotypes of these properties are distributed independently with left-handed and right-handed people.

If, after arms folding, the right arm is above the left forearm, the phenotype is characterised as R (right; the right type), and in the opposite case, i.e. if the left arm is positioned above the right, it is the phenotype L (left; left-type).[1][2][3]

Factors and history

Falk and Ayala (1971) found that variations in arm folding are largely inherited, but these variations are not governed by existing Mendelian models.[4] In this regard, Ferronato et al. (1974) found no significant correlation between parents and children.[5] Individual type of arms folding is slightly less studied than the manner of clasping hands. In search of the main factors that determine this dimorphism, the same difficulties emerge as with clasping hands. However, utilising the findings and the views of many authors,[6][7][8][9][10][11] it can be concluded that the manner of arms folding is hereditary and that it inherits the model that does not fit into the genetics concept of simple Mendelian characters, although in this respect there are contradictory findings. The main conclusion is that the manifestation of alternative phenotypes with these characteristics is irrespective of sex and age, and that it is not related to handedness.

Supporters of the assumptions that genetic factors play an important role in forming these properties are reinforced by the data of very heterogeneous frequencies of alternative phenotypes (R and L) in the explored portion of the world's population. But the point of view that basic genetics could explain the phenomena has also been put in discussion; it is not accepted by all researchers.[12] Luria (1947/1970) proposed left-top positions in arm folding (AF) and hand clasping (HC) to be signs of "latent left-handedness". While human beings are more right-handed as animals, it is supposed that left-handedness could be latent. Experiments support Luria's proposition that a left-top preference in Arm Folding points to "latent" left-handedness, but only if associated with a right-top preference in hand clasping.[13]

Phenotype R distribution

The data in the following table summarize R distributions in various areas as concluded by the cited studies.

Area N R (%) Reference
Belgium 626 43.6 Leguebe (1967)[14]
Bosnia and Herzegovina 10,073 46.5 Hadžiselimović et al. (1979)[15]
Germany 304 50.0 Ludwig (1932)[16]
Greece ? 45.4 Pelecanos (1969)[17]
Poland 771 35.3 Wolanski et al. (1973)[18]
Serbia: Užice 2,217 40.2 Hadžiselimović et al. (1979)[15]
Serbia: Voivodina 2,686 45.6 Gavrilović, Božić (1972)[19]
Spain 486 41.3 Pons (1961)[8]
Sweden 981 46.6 Beckman, Elston (1962)[20]

See also

References

  1. ↑ Ferronato, S.; Thomas, D.; Sadava, D. (1974). "Preferences for Handedness, Arm Folding, and Hand Clasping in Families". Human Heredity. 24 (4): 345–351. doi:10.1159/000152670. PMID 4461659.
  2. ↑ OMIM, Victor A. McKusick : 6/4/1986.
  3. ↑ Hadžiselimović, R.; Berberović, Lj; Sofradžija, A (1979). "Distribucija fenotipova načina sklapanja šaka i prekrštanja ruku u stanovništvu Bosne i Hercegovine" [Distribution of phenotypes of the way handcuffs and hands crossing in the population of Bosnia and Herzegovina]. God.Biol. Inst. Univ. U Sarajevu (in Croatian). 32: 101–16.
  4. ↑ Falk C. T., Ayala F. J. (1971): Genetic aspects of arm folding and hand clasping. Jpn. J. Hum. Genet., 15: 241-247. [PubMed: 4461659, related citations].
  5. ↑ Ferronato S., Thomas D., Sadava D. (1974): Preferences for handedness, arm folding, and hand clasping in families. Hum. Hered. 24: 345-351, 1974.
  6. ↑ Wiener, Alexander S. (1932). "Observations on the Manner of Clasping the Hands and Folding the Arms". The American Naturalist. 66 (705): 365–370. doi:10.1086/280443. S2CID 83590090.
  7. ↑ Quelce-Salgado, A; Freire-Maia, Ademar; Freire-Maia, Newton (1961). "Arm folding: A genetic trait?". Jinrui Idengaku Zasshi. The Japanese Journal of Human Genetics. 6: 21–5. PMID 14489425.
  8. 1 2 Pons, J (1963). "A contribution to the genetics of hand clasping and arm folding". Proc. Second Intern. Congr. Hum. Genet. (Roma). 1: 442–6.
  9. ↑ Kawabe, M (1949). "A study of the mode of clasping of the hands". Trans. Sapporo Nat. Hist. Soc. 18: 49–52.
  10. ↑ Freire-Maia, A.; De Almeida, J. (1966). "Hand clasping and arm folding among African Negroes". Human Biology. 38 (3): 175–9. JSTOR 41449259. PMID 5977525.
  11. ↑ Leguebe, A; Martines-Fuentes, A (1968). "Analyse génétique de deux caractères anthropologiques (Hand clasping and Arm folding)" [Genetic analysis of two anthropological characters (Hand clasping and Arm folding)]. Tudi VII Meždunarodnogo Kongresa Antropologičeskih I Etnografičeskih Nauk (in French). 1: 360–8. OCLC 1041385729.
  12. ↑ "Myths of Human Genetics: Arm Folding".
  13. ↑ Mohr, Christine; Thut, Gregor; Landis, Theodor; Brugger, Peter (2006). "Arm folding, hand clasping, and Luria's concept of "latent left-handedness"". Laterality: Asymmetries of Body, Brain and Cognition. 11 (1): 15–32. doi:10.1080/13576500500199795. PMID 16414912. S2CID 43327621.
  14. ↑ Leguebe (1967). "Hand clasping: étude anthropologique et génétique" [Hand clasping: anthropological and genetic study]. Bull. Soc. Roy. Antrop. Préhist (in French). 78: 81–107.
  15. 1 2 Hadžiselimović R., Berberović Lj., Sofradžija A. (1979): Distribucija fenotipova načina sklapanja šaka i prekrštanja ruku u stanovništvu Bosne i Hercegovine. God.Biol. inst. Univ. u Sarajevu, 32: 101-116.
  16. ↑ Ludwig W. (1932): Das Rechts – Links Problem im Tierreich und bei Menschen. J Springer Verlag.
  17. ↑ Pelecanos 1969, in: Pyżuk M. (1976): Hand clasping, and arm- and leg-folding in Polish rural population. Acta F. R. N. Univ Come., Anthropologia, 23: 219-223.
  18. ↑ Wolanski et al 1973, in: Pyżuk M. (1976): Hand clasping, and arm- and leg-folding in Polish rural population. Acta F. R. N. Univ Come., Anthropologia, 23: 219-223.
  19. ↑ Gavrilović Ž., Božić V. (1972): Proučavanje načina sklapanja šaka i pekrštanja ruku kod stanovništva u Vojvodini. Genetika, 4 (1): 59-61.
  20. ↑ BECKMAN L; ELSTON R (1962). "Data on bilateral variation in man: Handedness, hand clasping and arm folding in Swedes". Human Biology. 34 (2): 99–103. JSTOR 41448543. PMID 13866425.
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