O death, where is thy sting? O grave, where is thy victory?
Young Earth Creationists believe and teach that Humans and Apes from the same ancestors is impossible, yet that Foxes and Dogs from the same ancestors happened over a period of only 400 years or so from the time of Noah's Flood until the time of Abraham and Job.
It is difficult to get a detailed description of the differences between the actual genes in these numerous species. Genes being the feature that evolution "works on" in a well understood and demonstrable manner. A simpler to understand difference is the difference in the genomes, that is, the map that the genes are laid out on.
As an analogy, imagine you have a map of Los Angeles. It's a very old map. A lot of places on this map no longer exist, but for most purposes, this map will allow you to navigate your way around Los Angeles.
This map would not be as useful for navigating downtown San Diego. Many of the street names are the same. Both cities have a city hall, a police department. The Los Angeles map might provide a list of things you would expect to find in San Diego, but it would be wholly inadequate in helping find those things.
A genome map for Humans is quite useful for finding things in an Ape genome. About as useful as a 70-year-old map of Los Angeles.
A genome map for Dogs is not useful for finding things in the Fox genome. It is like using a Los Angeles map to find your way around San Diego.
In the genome map, the most obvious difference between Humans and Apes is that Humans have 23 pairs of chromosomes while Apes have 24. One specific pair of Human chromosomes have the genetic material of two specific pairs of Ape chromosomes. This pair of Human chromosomes look like the result of fusing the corresponding pairs of Ape chromosomes together and disabling some now redundant features.
In comparison, the Dog has 38 pairs of chromosomes and while the fox has 17 pairs of chromosomes. The article presented here http://cbsu.tc.cornell.edu/ccgr/behaviour/04_Recent_Publications/Fo... demonstrates that at least 47 breaks and fusions of the sort that occurs between the Human and Ape genomes would be required for Dogs and Foxes to come from a common set of parents.
Whatever the difficulty of proposed Human evolution from Apes in a certain number of generations, Dogs and Foxes from a common ancestor would require at least 47 times as many generations. This is a significantly higher hurdle for Young Earth Creationists to overcome. For Foxes and Dogs to come from a pair on the ark in some 400 years, only 100 to 200 generations, that same rate of evolution would require that Humans could produce Apes in 2 to 4 generations, and vice-versa.
This is why Young Earth Creationists are appropriately accused of being hyper-evolutionists. They believe that evolution after the flood occurred on this fantastically great and super-fast scale.