Please explain why these are bad genetics. I want to learn.
I wouldn't say they are "bad" genetics; blue-eyed whites, harlequins, and steel rabbits are all beautiful. But I'm guessing that
@Secuono might be referring to the fact that these three genes can produce a lot of kits that are not "recognized" colors. More difficult yet, the latter two - harlequin and steel - can interact with other genes to make the resulting kit colors very hard to identify and/or predict.
The first, VM (which stands for Vienna Marked), means the rabbit carries the vienna gene <v> that produces blue-eyed whites (BEW, when a rabbit gets two copies of it, one from each parent). This gene is partially dominant, meaning that one copy of it can either produce bunnies with some combination of one or two blue eyes or marbled eyes, and/or white marks on their body or toes, or it can hide behind the other colors the rabbit carries (making it a VC, or Vienna Carrier, which looks like a non-vienna rabbit). The point is that it is unpredictable: if the rabbit is BEW, you can't tell what other colors it carries; if it's VM, you won't necessarily know if the white marks are from the vienna gene, the dutch gene, or the broken gene, or something else; if it is a VC, you don't even know it's a vienna carrier until it produces some surprise-marked or off-colored eyed kits.
Next, in my opinion, the two most-complicated gene series are C and E, both having at least 5 alleles (an allele is a particular form of a gene), several of which are partially dominant. Harlequin and steel are both alleles on the E-series gene, which includes, in order of dominance:
Ed = "dominant black" (which is assumed to be very rare)
Es = steel
E = normal color
ej = harlequin
e = non-extension (makes reds and torts, for example)
The harlequin allele <ej> is the second-most recessive allele on the E-series, but it is still partially dominant. In a rabbit that carries two copies of it, or one plus the lower <e>, it causes the colors that would normally be divided into bands on a single hair, to be divided onto different hairs. For instance, if the bands/rings on the hairs would be black and orange, like on a chestnut <E_>:
the harlequin <ejej> or <eje> would have black on some hairs and orange on other hairs:
The problem is that one copy of the allele combined with an allele that's higher on the dominance scale can also cause this banding to show up "through" other colors, making, for instance, a "harlequinized chestnut."
@Buknee has a beauty in one of her litters - see photo #10 in:
https://rabbittalk.com/threads/hersheys-2nd-litter.36078/page-2
The steel allele <Es>, at the top of the dominance hierarchy, has several tricks up its sleeve. In combination with certain other genes (notably agouti), it makes a steel colored rabbit, either gold-tipped, or silver-tipped (with the addition of another tricky allele, the one for chinchilla).
This is a broken silver-tipped steel French Lop image from
Recognized Breeds
But in other combinations (in particular, combined with self), it can make a rabbit that looks black, or black with a few areas of light ticking. Further, if a rabbit gets two copies of the steel allele, it is called a "supersteel" and looks, again, like a black.
These are all fascinating if you're interested in the genetics of rabbit coat colors. We are actually trying to get the vienna genes into our Mini Rex rabbits so we can produce some BEW Mini Rex. But if you're just starting to sort through the basic genetics, or if you're trying to predict what colors your rabbits carry or will be, or if you're trying to produce show-quality purebred rabbits, these particular genes/alleles can be pretty frustrating.