Shaded life is completely genetically incompatible with life from other planets without heavy molecular messing. The reason for this is of course unknown to the residents before magogenetic techniques are developed. Secretly, it's because the Shaded genome has developed a way of protecting itself from mutations, which otherwise would occur far more frequently on Shade than elsewhere.
This applies to all known living things on Shade. It also means Shaded life is less vulnerable to certain sorts of virus and could explain why the naturalistic kinds of vampirism don't transmit. (OOCly, that's a lot more simply explained by Shade's author not being interested in writing vampire stories.)
Article below is old and will be updated, though probably still broadly accurate.
DNA and genes on Shade work similarly to those in our world.
It also means a slightly higher rate of pregnancy failures, though these generally occur at a clump-of-cells stage, long before the woman knows she's pregnant.
Domestic animals have been selectively bred virtually since the inception of livestock husbandry.
One famous case of genetic manipulation occurs during the Great War, orchestrated by outside forces not native to Shade. Magotechnology on Shade is nowhere near sophisticated enough at this point to have engineered anything on this sort of scale.
A century or two after the Twine Wars period, Shade develops magotechnological methods of manipulating genetic material at or around conception. Gene therapy in children and adults is also understood and employed but the results are nonheritable.
Following on the traditions of selective breeding, animals classed as domestic have been genetically altered. Strict welfare (and consent, where appropriate) laws are in place. These are more thorough, and more thoroughly upheld, than on most known worlds with this technology. This stems from Shade's trademark holding of animals in unusually high regard.
It's forbidden to tamper with wild-classified animal species, by breeding or magogenetic methods, except in extraordinary circumstances threatening the species' survival.