If textbooks evolve, then what we thought we knew yesterday is no longer true today.
There’s a famous scene in an Indiana Jones movie where the hero barely makes it under a closing gate descending on him in an underground tunnel.
Independent groups of researchers (e.g., Hössjer et al. 2016), more or less skeptical of common ancestry, have suggested the alternative model of initial heterozygotic diversity.
Let’s have a little respect here.
Although DNA is involved in specifying the amino acid sequences of proteins, other sources of information are needed to specify the three-dimensional structure of the embryo.