Effects of
dilute locus mutants on


blackwing Archangels



By - Tim Kvidera

The copper blackwing Archangel, see photo #1, is the result of the location, locus, of the dilute gene on the sex chromosome being non-mutated, wild type. Being wild type at the dilute locus causes the expression of gimpel bronze to be a deep, rich, dark red bronze referred to as copper. Copper is what had been often called dark bronze in the past.

What was called light bronze, and now gold blackwing, see photo #2, has the dilute locus mutated to pale which is an alternative mutation, allele, at the same position on the sex chromosome as dilute. Pale lessens the expression of color, but not as extensively as dilution does. Pale is termed a recessive mutation. That is, a cock who is carrying a pale gene, heterozygous for pale, will appear to be intense in color, wild type. This cock will produce both wild type and pale hens. Remember hens only have one sex chromosome and they receive that via the father's sperm. Cocks have two sex chromosomes and receive one from each parent. An interesting effect of pale is it has much more impact on the gimpel bronze body than it does on the wing shield, flights and tail. It transforms the dark copper to a bright gold while leaving the wings and tail almost black. If compared to the intensity of a copper blackwing black to the gold blackwing "black" there is a discernible lightening of the gold blackwing's "black." But it looks much blacker when contrasted to the light gold.

A fairly recently discovered dilute allele, extreme dilute, is the causative gene for what Jack Barkel termed lemon which he found in South African Racing Homers. This lemon gene is another recessive allele to wild type at the dilute locus which extremely lessens the intensity of the pigment. An extreme dilute blue bird is a very light tan. When I got my start in this lemon mutation via a bird from Larry Davis, directly down from lemons he got from the Barkel Breeding Station, I wanted to see what effect lemon would have on a bird with the many assorted color intensifying modifiers that Archangels have. I crossed the blue check lemon Racing Homer hen to a high end gold blackwing Archangel cock from my line of recent German imports. All youngsters were pale "T" checks with gold chest crescents, both hens and cocks. This indicated that lemon was more recessive than pale and an allele to pale, otherwise the young cocks would have been wild type in intensity.

These young cocks were then paired to gold blackwing Archangel hens to achieve homozygous, pure, gimpel bronze with some of the young hens also being lemon. The extreme dilute, lemon, hens that were gimpel bronze were somewhat darker in wing shield color than "typical" "T" check or spread (black) Homer lemons and moulted to a bright, shiny ivory shade in the gimpel bronze head, neck and body. I have named them ivory butterscotchwing, see photo #3, to describe the expression and to be somewhat consistent with Archangel color terminology. But even with all the color intensifying genome of the Archangel, extreme dilute lightens the blackwing shields to a tan shade not much darker than the few black lemon Homers that I have seen, which had unknown amounts of color intensifying modifiers. Extreme dilute is a powerful lightener which drives the color of the bird to light tan shades.

When some German Archangels were imported 15 or 20 years ago it was quickly noted that the gold of the new birds was lighter and brighter than the domestic American gold blackwings. It was suggested that maybe they were not pale, but rather dilute, to get the lighter color. To that end I set out to intentionally create the dilute version of the copper blackwing. I had a dilute hen who was heterozygous for gimpel bronze from a Indian Fantail project. She was paired to a copper blackwing cock known to be homozygous for wild type at the dilute locus. No potential for pale to interfere with or confuse the project. Heterozygous dilute cocks were made which were in turn paired to copper blackwing hens to drive towards homozygous copper blackwing genome while producing a few dilute hens. These dilute hens were again put back onto copper blackwing cocks and their young cocks again onto copper blackwing hens to again enhance the Archangel genome and see its effects on the dilute young hens.

Dilute gimpel bronze is lighter and much drabber than pale gimpel. The wing shield, flights and tail are dun shade as one would expect of a dilute black. In keeping with the scheme of naming Archangel colors descriptively I think that calling dilute gimpel Archangels pyrite dunwing would be appropriate, see photos #4 and 5. Although their head, neck and body are similar to Archangel gold, it is a "fool's gold" approximation and a dilute of black is dun.

The imported German gold blackwings do not owe their lightness to dilution. Why are these German gold blackwings so much brighter and lighter than the old domestic gold blackwings? Some think that they may have some added gene that the domestic birds do not have. I tend to think that it could just as well be that the new golds have less rather than more.

Traditional wisdom among Archangel breeders is to never pair coppers to golds - it destroys both.

It is highly probable that in selecting for the deep, rich, dark copper bronze the breeders have selected for a different set of background genes than those who selected for the bright, light gold. If the genes needed to make the show copper are mutations from wild type and eliminating some of those genes results in the bright, light golds; it may not be a matter of what the new golds have, but rather what do they not have which makes them the new shade.