This page for the listing of other genes that are not related to color or fur type. Some 'other' genetics are more well understood, while others have not been researched or well documented. For those that are unknown, we may not have a lot of information other than that genetics do play a role in these types of rabbits.
The dwarf gene is a common and well understood gene in small breeds (including but not limited to dwarfs). It's what makes these small bunnies so tiny! It's even responsible for making those cute little squishy faces, small ears, and stubby feet that we love to see in our dwarf bunnies, since it naturally causes those types of features. Rabbits without the dwarf gene are more likely to have more elongated features. When you compare siblings, one with the dwarf gene and one without, you'll often notice the difference (though not always, as there is certainly selective breeding at play in the case of many dwarf breeds).
But with cuteness does come some drawbacks. When breeding dwarf breeds, it's important to understand the lethal consequences of breeding these features. The dwarf gene has the potential to cause deformities when two copies are present. One copy of the gene is needed for dwarfism, but two copies will result in a (almost always) lethal kit with internal deformities. These kits are referred to as 'peanuts' and are usually much smaller than their siblings who have one or no copies of the dwarf gene. Pictured above is a peanut (dwdw) and its dwarf (Dwdw) sibling.
Peanuts may also have other visibly deformed features. They rarely survive longer than 2 weeks. For this reason, it's best to pair rabbits who have one copy of the dwarf gene (Dwdw) with a non-dwarf (DwDw). The dwarf to non-dwarf pair will guarantee that no peanuts are conceived.
Did you know? - Although the dwarf gene can cause small/short features, selective breeding can too. Some small sized breeds such as the Britannia Petite (aka Polish outside the US) were origignally bred down in size without the aid of the dwarf gene. It is also possible to have dwarf-like features without the dwarf gene, which can be seen in breeds like the Netherland Dwarf and Holland Lop in individuals who don't have the dwarf gene at all, but still retain noticeable dwarf-like features.
Some breeders (especially of breeds such as the Britannia Petite) prefer to retain the 'non dwarf' bloodlines. They benefit from keeping the dwarf gene out of their bloodlines because they do not have to worry about the potential for peanuts and generally experience larger litters.
Deconfuzzled - Which breeds are dwarfs and which aren't?! Unfortunately, the name or the size of a breed is not always a true indicator of whether or not they have the dwarf gene. Mini Rex, Holland Lops, and Lionheads are examples of some of the smaller breeds that typically have the dwarf gene, but do not have the word 'Dwarf' explicitly in their name. Also, smallness of a breed doesn't mean they're dwarfs. Dutch, Tans, and Himalayans are notable examples of small breeds that don't have the dwarf gene. Also, the United STates Polish, which is often considered a dwarf breed, may not always have the dwarf gene because they were developed from an (originally) non-dwarf breed, the Britannia Petite. Many Polish do have the dwarf gene, but it very much depends on the bloodline.
Because presence of the dwarf gene depends so much on the bloodline and individual rabbit (rather than the breed), it's always a good idea to consult with the breeder if you want to know for sure about a rabbit's genetic lineage.
'Snowballing' refers to when a kit (a young rabbit) has white in its undercoat. The top color of the fur will be a normal color, but with white underneathe. Not much is known about this bizarre coloration, but it usually molt out of the adult coat and it is commonly known to have a genetic component. Breeders os show animals tend to avoid keeping bloodlines that produce snowballing kits.