Pigmi: Perbedaan antara revisi

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Berbagai teori telah diajukan untuk menjelaskan rata-rata tinggi pygmy yang pendek. Beberapa penelitian menunjukkan bahwa hal tersebut merupakan adaptasi terhadap tingkat [[sinar ultraviolet]] yang rendah di [[hutan hujan]].<ref>{{cite journal|doi=10.1002/ajpa.21512|title=Indirect evidence for the genetic determination of short stature in African Pygmies|year=2011|last1=Becker|first1=Noémie S.A.|last2=Verdu|first2=Paul|last3=Froment|first3=Alain|last4=Le Bomin|first4=Sylvie|last5=Pagezy|first5=Hélène|last6=Bahuchet|first6=Serge|last7=Heyer|first7=Evelyne|journal=American Journal of Physical Anthropology|volume=145|issue=3|pages=390–401|pmid=21541921}}</ref><ref>{{Cite web |title=Ultraviolet light levels in the rainforest |url=http://julianodea.blogspot.com/2009/12/ultraviolet-light-levels-in-rainforest.html |author= Dr Julian O'Dea |date=December 21, 2009}}<!-- data originally published in "a newsletter put out by the Australasian Society for Human Biology". Probably very simliar to below cited reference by same author. --></ref> Hal ini menunjukkan bahwa hanya sedikit vitanmin D yang dapat dibuat di kulit manusia, sehingga membatasi serapan [[kalsium]] dari makanan yang penting dalam pertumbuhan dan pemeliharaan tulang.<ref name=o>O'Dea, JD. Possible contribution of low ultraviolet light under the rainforest canopy to the small stature of Pygmies and Negritos. Homo: Journal of Comparative Human Biology, Vol. 44, No.3, pp. 284–7, 1994.</ref>
 
Penjelasan lain meliputi kurangnya makanan di lingkungan hutan hujan, kadar kalsium yang rendah di tanah, keperluan untuk berpindah di hutan yang padat, adaptasi terhadap panas dan kelembaban, dan kematangan reproduktif yang cepat akibat risiko kematian awal.<ref>[http://notexactlyrocketscience.wordpress.com/2007/12/19/short-lives-short-size-why-are-pygmies-small/ Short lives, short size – why are pygmies small? « Not Exactly Rocket Science<!-- Bot generated title -->].</ref> (See also [[Aeta people#Demographics]]<!-- for related academic sources -->.) Bukti lain mengarah kepada rendahnya ekspresi gen yang menyandi [[reseptor hormon pertumbuhan]] dan [[hormon pertumbuhan]].<ref name='Bozzola, 2009'>{{cite journal | title = The shortness of Pygmies is associated with severe under-expression of the growth hormone receptor | journal = Mol Genet Metab | date = 2009 Nov | first = M | last = Bozzola | coauthors = Travaglino P, Marziliano N, Meazza C, Pagani S, Grasso M, Tauber M, Diegoli M, Pilotto A, Disabella E, Tarantino P, Brega A, Arbustini E | volume = 98 | issue = 3 | pages = 310–3 | pmid=19541519 | doi=10.1016/j.ymgme.2009.05.009}}</ref>
 
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