Dominant Grey Budgerigar Mutation
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The Dominant Grey budgerigar mutation, often called the Australian Grey or simply Grey, is one of approximately 30 mutations affecting the colour of budgerigars. It is the basis of the Grey-Green and Grey standard varieties.


Appearance

The Dominant Grey mutation transforms the wild-type Light Green into the Grey-Green variety and the Skyblue into the Light Grey variety. The body colour of the Grey-Green is a dull mustard green and, compared to a Light Green, the mask is a slightly duller tone of yellow. The body colour of the Light Grey is an even, uniform, battle-ship grey. In both the blue and green series birds the flights and long tail feathers are black. The pattern of black on the wing and tail markings is unchanged, but they are darkened to a jet black, resulting in high contrast between the black and yellow, which is particularly noticeable in the tail bar when the bird is in flight. The cheek patches are lilac-grey. When combined with the Dark mutation the body colour of both Greys and Grey-Greens becomes slightly darker, but the effect is much smaller than the effect of the Dark mutation on Light Greens and Skyblues. As this is a dominant mutation the colour changes described above apply to both single factor (SF) and double factor (DF) Greys and Grey-Greens. The only difference between SF and DF birds is in the colour of the afterfeather and shaft (see
Feather Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and a premier ...
) of the contour feathers. In the SF Light Grey these are the normal white but in the DF birds the afterfeather is dark grey, with a black shaft. The World Budgerigar Organisation has established precise standards for budgerigar body colours using the
Pantone Pantone LLC (stylized as PANTONE) is a limited liability company headquartered in Carlstadt, New Jersey. The company is best known for its Pantone Matching System (PMS), a proprietary color space used in a variety of industries, notably graphic ...
Codes, as shown to the right.


Historical notes

The earliest recorded appearance of the Dominant Grey mutation was in 1934, when S Harrison of Murrumbeena, Victoria, Australia, purchased a Grey cock from a dealer. The original breeder has not been identified. Early breeding results showed this Grey to be a Dark Grey (SF)/ dilute, and Mrs Harrison went on to establish a substantial strain of Greys from this bird. In 1936, it was reported that W F Shepherd of Kew, Victoria, also had Greys which he obtained from a colony breeder, and a Grey was also bred independently by R Hancock of Beverley, South Australia, in 1935. Dominant Greys were first imported to Britain around 1937, one by R Brown of Morecambe for Walter Higham, and one, from R Hancock's stock, by Tom Goodwin.


Genetics

The Dominant Grey
allele An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chro ...
is dominant over its wild-type allele, so a bird possessing a single Dominant Grey allele (the
heterozygote Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Mo ...
or single-factor Dominant Grey) is converted from the wild-type Light Green to Grey-green as described in Appearance above. That is, the presence of a single Dominant Grey allele is sufficient to permit the full expression of the mutation. The double-factor Dominant Grey, with two Dominant Grey alleles, is identical in appearance to the single-factor Dominant Grey, although there is some evidence that the colour of the breast afterfeathers is changed from white to grey in the double-factor bird. The Dominant Grey gene is located on one of the autosomal
chromosomes A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...
. There is no known linkage of this gene with any other mutation.


Notes


References

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External links


World Budgerigar Organisation (WBO)


{{Budgerigar mutations Budgerigar colour mutations