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The anatomical placode in reptile scale morphogenesis indicates shared ancestry among skin appendages in amniotes

View Article: PubMed Central - PubMed

ABSTRACT

Researchers show that scales, feathers, and hairs of reptiles, birds, and mammals evolved from the scales of their common reptilian ancestor.

No MeSH data available.


Related in: MedlinePlus

Absence of anatomical placodes in scaleless P. vitticeps skin.(A to C) WMISH showing the expression of early markers of epidermal appendage development in WT and Sca bearded dragon embryos at various indicated developmental stages: (A) Shh; (B) Ctnnb1; and (C) Edar (left), Eda (center), and Bmp4 (right). Left panels show the WMISH signal on the lateral skin region, and right panels show parasagittal cryosections of the corresponding regions. Insets show high magnifications of the staining and indicate the presence/absence of placode formation in WT and mutant skin, respectively.
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Figure 4: Absence of anatomical placodes in scaleless P. vitticeps skin.(A to C) WMISH showing the expression of early markers of epidermal appendage development in WT and Sca bearded dragon embryos at various indicated developmental stages: (A) Shh; (B) Ctnnb1; and (C) Edar (left), Eda (center), and Bmp4 (right). Left panels show the WMISH signal on the lateral skin region, and right panels show parasagittal cryosections of the corresponding regions. Insets show high magnifications of the staining and indicate the presence/absence of placode formation in WT and mutant skin, respectively.

Mentions: Scaleless dragons do no exhibit any Shh expression in the skin (Fig. 4A, lower panels), whereas the Shh expression dynamic in wild-type dragons is first restricted at the center of the placode before it spreads in a larger and more posterior domain (Fig. 4A, upper panels). Similarly, Ctnnb1 and Edar, two other placode markers, also show marked differences in expression between wild-type and scaleless dragons. In both phenotypes, expression of these two genes is first ubiquitous across the whole epidermis before becoming restricted to the placodes in wild-type individuals only (Fig. 4B). These results indicate that expression of each of these three placode markers in reptiles is similar to the expression dynamic of the corresponding genes in mammals (27) and birds (20, 28, 39). On the other hand, the absence of an anatomical placode in scaleless dragons coincides with the inability of signaling pathways to pattern the skin, similar to what is observed in mice deficient in Eda/Edar (40). Note that both the functional Eda in wild-type dragons and the dysfunctional Eda in scaleless dragons are both expressed in the dermis [as in birds (31)], but the former remains diffused in scaleless lizards (Fig. 4C).


The anatomical placode in reptile scale morphogenesis indicates shared ancestry among skin appendages in amniotes
Absence of anatomical placodes in scaleless P. vitticeps skin.(A to C) WMISH showing the expression of early markers of epidermal appendage development in WT and Sca bearded dragon embryos at various indicated developmental stages: (A) Shh; (B) Ctnnb1; and (C) Edar (left), Eda (center), and Bmp4 (right). Left panels show the WMISH signal on the lateral skin region, and right panels show parasagittal cryosections of the corresponding regions. Insets show high magnifications of the staining and indicate the presence/absence of placode formation in WT and mutant skin, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5392058&req=5

Figure 4: Absence of anatomical placodes in scaleless P. vitticeps skin.(A to C) WMISH showing the expression of early markers of epidermal appendage development in WT and Sca bearded dragon embryos at various indicated developmental stages: (A) Shh; (B) Ctnnb1; and (C) Edar (left), Eda (center), and Bmp4 (right). Left panels show the WMISH signal on the lateral skin region, and right panels show parasagittal cryosections of the corresponding regions. Insets show high magnifications of the staining and indicate the presence/absence of placode formation in WT and mutant skin, respectively.
Mentions: Scaleless dragons do no exhibit any Shh expression in the skin (Fig. 4A, lower panels), whereas the Shh expression dynamic in wild-type dragons is first restricted at the center of the placode before it spreads in a larger and more posterior domain (Fig. 4A, upper panels). Similarly, Ctnnb1 and Edar, two other placode markers, also show marked differences in expression between wild-type and scaleless dragons. In both phenotypes, expression of these two genes is first ubiquitous across the whole epidermis before becoming restricted to the placodes in wild-type individuals only (Fig. 4B). These results indicate that expression of each of these three placode markers in reptiles is similar to the expression dynamic of the corresponding genes in mammals (27) and birds (20, 28, 39). On the other hand, the absence of an anatomical placode in scaleless dragons coincides with the inability of signaling pathways to pattern the skin, similar to what is observed in mice deficient in Eda/Edar (40). Note that both the functional Eda in wild-type dragons and the dysfunctional Eda in scaleless dragons are both expressed in the dermis [as in birds (31)], but the former remains diffused in scaleless lizards (Fig. 4C).

View Article: PubMed Central - PubMed

ABSTRACT

Researchers show that scales, feathers, and hairs of reptiles, birds, and mammals evolved from the scales of their common reptilian ancestor.

No MeSH data available.


Related in: MedlinePlus