There is a lot yet to be discovered but sadly most have bought into the fiction of humans and apes being 98/99% genetically identical. It just isn’t true even the number of chromosomes are different and the epigenetic code which controls how genes are expressed are highly different. Even Mice and humans share 99 percent of the same genes if you don’t consider epigenetics. Most creatures share genes from a common genetic tool kit. The genes are equivalent to functions used in programs. The epigenetic code is the control code and it is what makes a mouse a mouse, an ape an ape and a man a man.
http://archives.cnn.com/2002/TECH/science/12/04/coolsc.coolsc.mousegenome/
And what makes tigons, ligers, zorses, geeps and other weird combinations?
Irrelevant. There are horse breeds with different numbers of chromosomes, and they can successfully interbreed, demonstrating that their DNA is very compatible.