As a RL breeder, I'm interested to see if anything in the Roo game acts like a true dominant. It's much harder to prove out than a recessive.

A couple of rules for dominants:

A dominant will always be visible if it is present.
A dominant cannot be carried (otherwise it would be a recessive).
A dominant is loseable. If the offspring doesn't show it, it doesn't have it.

In the various breedables I've done in SL, I have found that everything is carryable, so thus no true dominants. I would be very interested in anyone's findings to prove out existence of true dominants.

Of course, we probably aren't far enough out to prove something has been lost. As they say in RL "recessive is forever" (which isn't entirely true but it can be very difficult to shake an undesirable recessive, unlike a dominant where you can simply select offspring without that dominant trait and they can never throw it).