Molecular Evolution and Protein Structure Variation of Dkk Family

The study examines the molecular evolution and protein structure variation of the Dkk gene family, which is crucial for regulating the Wnt signaling pathway involved in hair follicle development. It highlights significant evolutionary changes in Aves and Reptilia, with accelerated evolution and positive selection at specific sites. Functional divergence analysis shows that amino acid variations in the Cys-2 domain may influence Dkk protein binding to LRP5/6, affecting Wnt signaling inhibition and leading to different functions of Dkk1, Dkk2, and Dkk4 in skin hair follicle development. The study notes that Dkk1 negatively regulates hair follicle development, Dkk2 affects plantar hair follicles, and Dkk4 is involved in primary hair follicle development. The findings suggest adaptive evolution and functional divergence in the Dkk families of Aves and Reptilia, contributing to the understanding of vertebrate skin appendage evolution.