Yeah, and if you start out trying to understand genetics with a tricky steel in the mix (actually several of the E series alleles are tricky), you may end up in a semi-permanent state of confusion!
The big question in my mind is whether both her sire and dam were/looked like chinchilla. The NZ/Flemish would have been the source of the steel, but it's perplexing to me how it could have "hidden" in two ensuing generations of rabbits with chinchilla phenotypes. Let me see if I can explain why that would be so perplexing...bear with me...
The "basic" or wild type rabbit is chestnut. It's an agouti with the most common (and with only one exception, the most dominant) alleles (an allele being a form of the gene). Many genes have multiple options/alleles, but usually one of them dominates - kind of covers up - any of the others in the same series.
A = agouti
B = black
C = full color
D = dense
E = normal extension of ring color,meaning how the rings are arranged on each hair. This is the only one that's
not the most most dominant form of the gene, which is very important for this discussion. Specifically, the steel allele <
E(S)> is more dominant than the normal <
E>.
It's helpful to me to realize that some loci (plural for locus, which is a specific spot on the chromosome) code for color (B C and D), while others control the pattern (A and E).
There are a few other loci that produce patterns like broken, silver, dutch, etc., but we don't need to talk about those here.
So...
CHESTNUT is <
A_B_C_D_E_>. When you start substituting less common alleles for the dominant ones at any of those five loci, you change either the color, or the pattern, or both.
CHINCHILLA: To "make" a chinchilla instead of a basic chestnut, all it takes is one substitution, at the C locus (a
color allele). Replace the <
C> with the chin allele <
c(chd)>, and the rabbit's pigment-making cells (melanocytes) can't make any yellow-based colors (gold, red, orange, tan, fawn, etc.). All that can be made are dark-based colors (black, blue, chocolate, lilac). So a chinchilla is just a black-and-white version of a chestnut, with the orange removed (no yellow pigment on the middle ring, so it looks pearly white). So, chinchilla is <
A_B_c(chd)_D_E_>.
STEEL (GTS): To "make" a steel instead of a chestnut, it similarly takes one substitution, at the E locus (a
pattern allele). The steel allele doesn't change the color - there is still both black and gold color on the rabbit (it's also called a "gold-tipped" steel, GTS). What the allele <
E(S)> does is stretch the undercolor up the hairshaft, in effect smooshing the agouti bands up towards the tip of the hair, and making the belly fur and trim (both of which are shorter hairs) look darker. So a steel is a chestnut agouti with a slightly messed-up ring pattern and trim: <
A_B_C_D_E(S)_>
SILVER-TIPPED STEEL (STS): When you put both of those alleles together - a color and a pattern change - you get a rabbit with no gold and a messed-up pattern, aka a silver-tipped steel: <
A_B_c(chd)_D_E(S)_>
So the mystery for me is related to the fact that when a chinchilla rabbit has a steel allele, it will
not look like a normal chinchilla, because the steel allele <
E(S)> is dominant to the normal allele <
E>. That means steel can't "hide" in an agouti rabbit (unless there are
two steel alleles, but that's a different issue - the rabbit still would not look like a chinchilla). So if a rabbit with both chinchilla and agouti alleles also has a steel allele, it
should look like a silver-tipped steel (STS), not a chinchilla. It may be that rabbits listed as chinchilla on the pedigree were actually really STS all along. But if there's one thing I know for sure in genetics, it's that I should never say never (or always).
So I'm wondering if you have, or saw, your doe's parents, and if they looked like normal chinchillas. You'd be looking for that tell-tale dark belly, since the surface color can be confusing. After a while you start to really see the difference, but it's something that confuses a lot of people at the outset, especially since both steels and agoutis develop their patterns as they grow. You may also start to notice steel kits in the nest box, by their dark ear lining, instead of the light inner ears of a regular agouti.
If you really like the steels, just keep breeding them, and eventually all you'll get will be steels. Oh, except for that exception I mentioned about two steel alleles... that makes a "supersteel" which looks like a plain black rabbit.