Hello welcome to my question! I was wondering which mutation/gene will carry on and how you could tell? I mean I have one with (HH) Spirit Wings. I've tried to test it with multiple others threw breeding but the wings don't seam to pass down. It's kinda frustrating because I want to get deeper into the breeding and mutations but I guess I just need a little help figuring it out. Thank you for your help.

this is not the place for questions, its for player created guides. for any other wuestions put it in the qna forum. anyway this is a full, detailed guide for breeding. this one gives info on genetics too

The guides Encryption gave you should explain the mechanism of it and all you can do with traits selection but to explain shortly, any traits before (HH) will be dominant on that specific trait. If you want to increass your chances to get an offspring with spirit wings visible you have to breed a pet that have the traits (II), (JJ), (KK) or (LL). Breading with a pet that have (HH) will garentee you to get the trait you are aiming for since there is no other options.

Thank you both for all your help! And next time ill put my question in the right area next time. Again sorry about that.