Isn't this wrong?

[Dracoluna]

In reality, it depends on the genetics of the animals. Like someone mentioned, it can bring out desirable and undesirable traits but that depends on what the animal carries. It just depends on the line. Even mammals are line bred on a regular basis if you look at the lineage of purebred dogs, cats, and horses. It enhances certain traits and in some cases, makes you realize that there was an undesirable recessive trait there when you get offspring who express it. Also, remember that siblings are not 100% genetically similar so one may carry an undesirable gene while the other might not thus producing offspring who may carry it but won't show it.

Here's an example. Let's say you're trying to get albinos and we'll pretend ultramelanistic is an undesirable trait.
Genetic Wizard 3.0 calculations by

As you can see, these two could be siblings who were bred but because one didn't carry the negative gene, none of the offspring were affected. In this case, you wouldn't know that any negative gene was carried since you got all healthy offspring

In this example, both parents carry the undesirable trait and so you see it in the offspring telling you that the genetics are there. In this case, I wouldn't do the pairing again because you know that both parents are carriers. By bringing in outside blood in this case, you'd lower the risk.
Genetic Wizard 3.0 calculations by