It is possible to produce an offspring from a zebra mating with a donkey. indeed, in the summer of 2012 in florence, italy, a male zebra climbed a zoo fence in order to mate with a female donkey. this resulted in the donkey giving birth to a live organism. however, this mating would not likely happen in the wild. which reproductive barrier would prevent this from occurring?

It is possible to produce an offspring from a zebra mating with a donkey. Indeed, in Florence, Italy, a male zebra mated with a female donkey and produced a striped mule.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."