Both Cat and Pig have 38 chromosomes, source: https://en.wikipedia.org/wiki/List_of_organisms_by_chromosome_count So, why we cannot crossbreed them? If we take Pig’s spermatozoon and Cat’s egg cell (or vice versa - Pig’s egg cell and Cat’s spermatozoon) and try to merge them what will happen? Can we in principle receive the zygote contained 19 chromosomes from Cat and 19 from Pig? I never heard this to be done, why? Maybe zygote will be formed, but then it dies? As far as I am aware the major reason is immunological intolerance between spermatozoon and egg cell belonging to different species – one cell will simply destroy other, right? Can we avoid this problem? Imagine that we have got Cat’s spermatozoon and Cat’s egg cell containing Pig’s 19 chromosomes (In order to do it we will have to remove Pig’s all 19 chromosomes from Pig’s egg cell and put them into Cat’s egg cell. As I know it is impossible now). We merge these two cells, then what? Will we receive Cig (Cat+Pig)? Will cellular differentiation occur? Do the various genes (half from Cat and the rest half from Pig) struggle with each other?