One Source for Scales, Feathers and Hair

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Nicholas St Fleur, One Source for Scales, Feathers and Hair. New York Times, June 28, 2016.
http://www.nytimes.com/2016/06/2 ... ommon-ancestor.html

Note:
(a) "placodes — tiny bumps of thick tissue found on the surface of developing embryos"

placode (n; etymology): "localized thickening of the ectoderm 外胚層 in a vertebrate embryo which contributes to the formation of a sensory organ, ganglion, feather or scale, etc"
http://www.oxforddictionaries.com/definition/english/placode

(b) "Scientists had previously found placodes on the embryos of birds and mammals, where they develop into feathers and hairs, but had never found the spots on a reptilian embryo before. * * * they were investigating why certain bearded dragons are born without scales. By analyzing the genomes of the naked bearded dragons, they narrowed down the culprit to a mutation in a single gene, called EDA, which is also known to disrupt placode development in birds and mammals. In humans, EDA gene mutations can lead to hypohidrotic ectodermal dysplasia, which causes people to develop abnormal teeth, nails and sweat glands."
(i) The EDA gene encodes the ectodysplasin A protein.
(A) ectodysplasin A
https://en.wikipedia.org/wiki/Ectodysplasin_A
(B) Genomic Home Reference, US National Library of Medicine, undated.
https://ghr.nlm.nih.gov/gene/EDA
(ii) English dictionary:
* ecto- (combining form; from Greek ektos outside, from ek, ex out)
* hidrotic (adj; from Greek noun hidrōs sweat)

(c) "their paper, published in the journal Science Advances"

Nicolas Di-Poï and Michel C Milinkovitch, The Anatomical Placode in Reptile Scale Morphogenesis Indicates Shared Ancestry Among Skin Appendages in Amniotes. Advances (a publication of Science), _: _ (online publication: June 24, 2016).
(d) Pogona
https://en.wikipedia.org/wiki/Pogona
(a genus; often known by the common name bearded dragons)