“And only the Designer has the password to change the DNA.”
DNA is already programmed with a wide range of variation. Sometimes traits are selected and sometimes they remain dormant. Environment may play a role. If a pack of dogs live in a cold region then the genes for long hair may become dominant for example. The information was already there for long hair. After breeding together with other long haired dogs over time the information for short hair can be bred out.
Some traits can be selected by humans by breeding certain dogs together. This leads to a loss of genetic information which is how we end up with a pure breed. To get away from the pure breed you have to reintroduce the information. IOW, breed a pure bred with another dog.
Thanks about my tagline. It wasn’t original. I stole it from a friend.
Use a different book to teach your kiddies about genetics and biology, because you are wrong.