Molecular evolution and expression of archosaurian ß-keratins: diversification and expansion of archosaurian ß-keratins and the origin of feather ß-keratins.
J Exp Zool B Mol Dev Evol
; 320(6): 393-405, 2013 Sep.
Article
en En
| MEDLINE
| ID: mdl-23744807
ABSTRACT
The archosauria consist of two living groups, crocodilians, and birds. Here we compare the structure, expression, and phylogeny of the beta (ß)-keratins in two crocodilian genomes and two avian genomes to gain a better understanding of the evolutionary origin of the feather ß-keratins. Unlike squamates such as the green anole with 40 ß-keratins in its genome, the chicken and zebra finch genomes have over 100 ß-keratin genes in their genomes, while the American alligator has 20 ß-keratin genes, and the saltwater crocodile has 21 ß-keratin genes. The crocodilian ß-keratins are similar to those of birds and these structural proteins have a central filament domain and N- and C-termini, which contribute to the matrix material between the twisted ß-sheets, which form the 2-3 nm filament. Overall the expression of alligator ß-keratin genes in the integument increases during development. Phylogenetic analysis demonstrates that a crocodilian ß-keratin clade forms a monophyletic group with the avian scale and feather ß-keratins, suggesting that avian scale and feather ß-keratins along with a subset of crocodilian ß-keratins evolved from a common ancestral gene/s. Overall, our analyses support the view that the epidermal appendages of basal archosaurs used a diverse array of ß-keratins, which evolved into crocodilian and avian specific clades. In birds, the scale and feather subfamilies appear to have evolved independently in the avian lineage from a subset of archosaurian claw ß-keratins. The expansion of the avian specific feather ß-keratin genes accompanied the diversification of birds and the evolution of feathers.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Aves
/
Evolución Molecular
/
Caimanes y Cocodrilos
/
Beta-Queratinas
/
Plumas
Límite:
Animals
Idioma:
En
Revista:
J Exp Zool B Mol Dev Evol
Año:
2013
Tipo del documento:
Article
País de afiliación:
Estados Unidos