So I am incredibly new to breeding but i understand the basics pretty well thanks to guides and basic biology classes, but one of my hatchlings seems to have spontaneously gotten a gene. neither parent carries any gene for that slot (they have both been tested) yet the baby carries one. What happened? Is it possible to inherit from grandparents? but only one was a carrier for that specific gene anyway so the odds are incredibly low if that is the case

A link to the specific pet would be helpful, but I'm guessing you're talking about this girl?

I'm not sure what happened either, but hey, who's gonna complain about an extra gene? :)

If it's the girl Valixene suspects it to be, it seems this way likely because the mom has not been tested.

It is likely that the mom is a carrier, having gotten the gene from the grandmother. Very low chances, but the grandmother's carry got passed on to the mom, but it's not seen (cause it's a carry) and it's not written in her genetics (cause the mom's not tested).
And when you breed the parents, the mom's carry gene got passed on to the girl now.

To be sure what each parent is carrying you can go genetically test them. If you don't have your own genetic tester, there are people who offer free services on the breeding forum. =)

Well You did test it, do you mind posting the father, the mother and the child in question?

Then again Perhaps this may answer your question if its the scenario Im thinking of. First off, the key that I will be using is: AA for visible, AN for carry and NN for nothing in the slot. Remember that even though NN has nothing in the slot you should still keep NN in mind cause it effects your genes. Also remember that parents can only give one of their gene slots to their children and that my %s are rounded based on that individual trait that can be passed from the parents and may not be completely accurate.

AA+AA= 100% visible trait. AA+AN= 75% chance that gene will be passed down as visible trait and in my opinion, is the best ratio to have when breeding. AN+AN= 50% as a visible trait.. AN+NN= 25% carry. I think you may have ended up with the scenario of AA+NN= 100% carry.

thanks guys! I think I figured it out and the mother was a hidden carrier :)