Scientists compare the development of digits on hands and feet in chicken and amphibians, in a study published on June 13 in Developmental Cell. The researchers report that cell death is restricted to the edges of the limb that form webbed feet in amphibians and have aquatic tadpoles. Frog species that develop to walk immediately on land and do not have interdigital webbing show cell death between digits, as do chickens. The authors report that the amount of oxygen surrounding the embryo helps to determine cell death in the areas between digits.
I.R. Cordeiro et al., “Environmental oxygen exposure allows for the evolution of interdigital cell death in limb patterning,” Dev Cell, doi:10.1016/j.devcel.2019.05.025, 2019.