[quote=@KaelRavenheart]
I have a question. Must the animals they are spliced with be mammals? Wouldn't it be more a diverse pool of genes if ot was expanded into other types, like avians and reptiles and amphibians and even certain traits of aquatic life?
[/quote]

They don't have to be mammals, they're just mostly mammals. Predators of reptilian and avian and amphibious are welcome as well. It's rare that a prey animals DNA would be used at all, let alone as the primary source for the experiments.