I've got it, came to me in a flash.
What actually happened is that there occured many, many Years ago a 4 chromosomes fusion, originating from Ape and male Gananoda was born. As he was the only one of his species he mated with a female Ape passing on two fused chromosomes to his offspring. These offspring felt superior and therefor would not mate outside their own kind and well .... you know the rest. Phewww was worried for a while there but now it's clear.
