It's really not THAT unusual that they share many of the same genes. They are after all both snakes, I'm sure all snakes share many different genes with each other, for instance we also share 97.3% of our genes with chimps. Also I find it handy to try to not think of it so much as a gene for albino, I like to think of it instead as a gene for 'something broken that now makes the production of melanin impossible.