Blue budgerigar mutation
Encyclopedia
The Blue budgerigar mutation is one of approximately 30 mutations affecting the colour of budgerigar
s. It is part of the genetic constitution of the following recognised varieties: Skyblue, Cobalt, Mauve and Violet.
changes the colour of the body feathers, which are light green in the wild-type, to skyblue and the colour of mask and other parts which are yellow in the wild-type, to white.
In the domesticated bird this mutation changes the Light Green variety into the Skyblue variety, the Dark Green into the Cobalt and the Olive into the Mauve.
The green colouration of the wild budgerigar is due to the combined effect of a yellow pigment
and an interference effect similar to that which gives colour to petrol on water, which in the budgerigar produces a blue colouration. Yellow pigment is present in the outer layer (cortex
) of the cells forming the barbs of all feathers of the wild budgerigar with the exception of the cheek patches, although it is very weak in the outermost flight feathers. The distribution of the yellow pigment is clearly shown in the Lutino. The Blue mutation totally inhibits the production of this yellow pigment, and as far as is known, it has no other effect.
The yellow pigment in young budgerigars is paler than in adults, which makes green budgerigars in nest feather appear duller and Lutinos appear paler. A brighter and stronger yellow colouration appears after the first moult
.
The chemical nature of the yellow pigment in budgerigars and other psittacidae is unknown,
and in the absence of a chemical name George A Smith coined the term "psittacins" to cover the yellow, orange and red pigments found in parrots and parrot-like birds. Psittacins impart a far more constant intensity of colour to feathers than do the more commonly found carotenoid
pigments such as xanthophyll
, the yellow pigment found in the canary
. At each moult the canary extracts xanthophyll directly from its food, and the depth of colouration of the growing feathers is determined by the concentration of xanthophyll in its diet. Budgerigars cannot be colour-fed in this way, because they do not use xanthophyll as a pigment.
The Blue mutation provides a widely accepted division of domesticated budgerigars into two colour classes: the "Green series" and the "Blue series". Birds of the Green series exhibit yellow pigmentation, while birds of the Blue series lack yellow pigmentation. These names can be misleading, since some birds belonging to the Blue series, such as Albinos, are not blue; similarly, Lutinos belong to the Green series, yet are not green.
In combination with the Dark budgerigar mutation
the body feathers become deeper shades of blue. A blue budgerigar with a single Dark factor is called a Cobalt, and one with two Dark factors a Mauve. The World Budgerigar Organisation has established precise standards for budgerigar body colours using the Pantone
Codes, as shown to the right.
made its first recorded appearance in 1878 in the aviaries of M Limbosch of Uccle
, a suburb of Brussels
, but this strain died out, it is believed, in 1881. Blues appeared independently in Holland between 1881 and 1885, and a Mr Pauwels of Everberg
, near Brussels, reintroduced them to Belgium
from this Dutch strain.
The first Blues to be seen in England were some exhibited by Messrs Millsum and Pauwels at the Horticultural Hall in 1910 and the Crystal Palace in 1911. Mr D Astley owned Blues in 1911
,
and it is recorded that C Pelham Sutton of Putney
bred a Blue in 1912.
Blues remained quite rare until the 1930s, fetching up to £100 per pair in Japan
around 1928, about the cost of a car at the time.
, so a bird possessing a single Blue allele (the heterozygote) is identical in appearance to the wild-type light green. That is, the presence of a single wild-type allele is sufficient to permit the full production of the yellow psittacin pigment. Among the budgerigar fancy such a bird is said to be a Light Green split blue, usually written Light Green/blue. In a bird which has two Blue alleles (the homozygote), the lack of the wild-type allele means the yellow pigment can no longer be produced, and so the body colour is blue — the Skyblue.
The locus
of the Blue gene is situated on one of the autosomal chromosome
s. The Yellowface Blue I mutation, the Yellowface II mutation
form an autosomal co-dominant series of alleles with the Blue mutation
.
The loci of the Dark budgerigar mutation
and the Blue allelic series are situated on the same autosome
, so the Dark mutation is linked to the Blue allelic series (see genetic linkage
). The cross-over value (COV) or recombination frequency between the Dark and Blue loci is commonly stated to be about 14%, but some experiments have found much smaller values (see Genetics in the Dark budgerigar mutation
).
Budgerigar
The Budgerigar , also known as Common Pet Parakeet or Shell Parakeet informally nicknamed the budgie, is a small, long-tailed, seed-eating parrot, and the only species in the Australian genus Melopsittacus...
s. It is part of the genetic constitution of the following recognised varieties: Skyblue, Cobalt, Mauve and Violet.
Appearance
The Blue mutationMutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
changes the colour of the body feathers, which are light green in the wild-type, to skyblue and the colour of mask and other parts which are yellow in the wild-type, to white.
In the domesticated bird this mutation changes the Light Green variety into the Skyblue variety, the Dark Green into the Cobalt and the Olive into the Mauve.
The green colouration of the wild budgerigar is due to the combined effect of a yellow pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
and an interference effect similar to that which gives colour to petrol on water, which in the budgerigar produces a blue colouration. Yellow pigment is present in the outer layer (cortex
Cell cortex
The cell cortex is a specialized layer of cytoplasm on the inner face of the plasma membrane that functions as a mechanical support of the plasma membrane. In animal cells it is an actin-rich layer responsible for movements of the cell surface. In plant cells, the cell cortex is reinforced by...
) of the cells forming the barbs of all feathers of the wild budgerigar with the exception of the cheek patches, although it is very weak in the outermost flight feathers. The distribution of the yellow pigment is clearly shown in the Lutino. The Blue mutation totally inhibits the production of this yellow pigment, and as far as is known, it has no other effect.
The yellow pigment in young budgerigars is paler than in adults, which makes green budgerigars in nest feather appear duller and Lutinos appear paler. A brighter and stronger yellow colouration appears after the first moult
Moult
In biology, moulting or molting , also known as sloughing, shedding, or for some species, ecdysis, is the manner in which an animal routinely casts off a part of its body , either at specific times of year, or at specific points in its life cycle.Moulting can involve the epidermis , pelage...
.
| Variety | Pantone Code |
|---|---|
| Light Green | 375 |
| Skyblue | 310 |
| Cobalt | 2915 |
| Mauve | 535 |
| Violet | 2727 |
The chemical nature of the yellow pigment in budgerigars and other psittacidae is unknown,
and in the absence of a chemical name George A Smith coined the term "psittacins" to cover the yellow, orange and red pigments found in parrots and parrot-like birds. Psittacins impart a far more constant intensity of colour to feathers than do the more commonly found carotenoid
Carotenoid
Carotenoids are tetraterpenoid organic pigments that are naturally occurring in the chloroplasts and chromoplasts of plants and some other photosynthetic organisms like algae, some bacteria, and some types of fungus. Carotenoids can be synthesized fats and other basic organic metabolic building...
pigments such as xanthophyll
Xanthophyll
Xanthophylls are yellow pigments that form one of two major divisions of the carotenoid group. The name is from Greek xanthos + phyllon , due to their formation of the yellow band seen in early chromatography of leaf pigments...
, the yellow pigment found in the canary
Domestic Canary
The Domestic Canary, often simply known as the canary, is a domesticated form of the wild Canary, a small songbird in the finch family originating from the Macaronesian Islands ....
. At each moult the canary extracts xanthophyll directly from its food, and the depth of colouration of the growing feathers is determined by the concentration of xanthophyll in its diet. Budgerigars cannot be colour-fed in this way, because they do not use xanthophyll as a pigment.
The Blue mutation provides a widely accepted division of domesticated budgerigars into two colour classes: the "Green series" and the "Blue series". Birds of the Green series exhibit yellow pigmentation, while birds of the Blue series lack yellow pigmentation. These names can be misleading, since some birds belonging to the Blue series, such as Albinos, are not blue; similarly, Lutinos belong to the Green series, yet are not green.
In combination with the Dark budgerigar mutation
Dark budgerigar mutation
The Dark budgerigar mutation is one of approximately 30 mutations affecting the colour of budgerigars. It is part of the genetic constitution of the following recognised varieties: Dark Green and Olive in the green series and Cobalt, Mauve and Violet in the blue series.- Appearance :Budgerigars...
the body feathers become deeper shades of blue. A blue budgerigar with a single Dark factor is called a Cobalt, and one with two Dark factors a Mauve. The World Budgerigar Organisation has established precise standards for budgerigar body colours using the Pantone
Pantone
Pantone Inc. is a corporation headquartered in Carlstadt, New Jersey, USA. The company is best known for its Pantone Matching System , a proprietary color space...
Codes, as shown to the right.
Historical Notes
The Blue mutationmade its first recorded appearance in 1878 in the aviaries of M Limbosch of Uccle
Uccle
Uccle or Ukkel is one of the nineteen municipalities located in the Brussels-Capital Region of Belgium.Uccle is known for its well-to-do areas, its green spots and its high rental rates.-History:...
, a suburb of Brussels
Brussels
Brussels , officially the Brussels Region or Brussels-Capital Region , is the capital of Belgium and the de facto capital of the European Union...
, but this strain died out, it is believed, in 1881. Blues appeared independently in Holland between 1881 and 1885, and a Mr Pauwels of Everberg
Everberg
Everberg is a town in the Belgian province Flemish-Brabant and is part of the municipality of Kortenberg. The territory contains an area of 925 ha. The neighbouring towns or municipalities are Leefdaal, Kortenberg, Erps-Kwerps, Meerbeek, Sterrebeek, Moorsel and Tervuren...
, near Brussels, reintroduced them to Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
from this Dutch strain.
The first Blues to be seen in England were some exhibited by Messrs Millsum and Pauwels at the Horticultural Hall in 1910 and the Crystal Palace in 1911. Mr D Astley owned Blues in 1911
,
and it is recorded that C Pelham Sutton of Putney
Putney
Putney is a district in south-west London, England, located in the London Borough of Wandsworth. It is situated south-west of Charing Cross. The area is identified in the London Plan as one of 35 major centres in Greater London....
bred a Blue in 1912.
Blues remained quite rare until the 1930s, fetching up to £100 per pair in Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
around 1928, about the cost of a car at the time.
Genetics
The Blue mutation is recessive to its wild-type alleleAllele
An allele is one of two or more forms of a gene or a genetic locus . "Allel" is an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation...
, so a bird possessing a single Blue allele (the heterozygote) is identical in appearance to the wild-type light green. That is, the presence of a single wild-type allele is sufficient to permit the full production of the yellow psittacin pigment. Among the budgerigar fancy such a bird is said to be a Light Green split blue, usually written Light Green/blue. In a bird which has two Blue alleles (the homozygote), the lack of the wild-type allele means the yellow pigment can no longer be produced, and so the body colour is blue — the Skyblue.
The locus
Locus (genetics)
In the fields of genetics and genetic computation, a locus is the specific location of a gene or DNA sequence on a chromosome. A variant of the DNA sequence at a given locus is called an allele. The ordered list of loci known for a particular genome is called a genetic map...
of the Blue gene is situated on one of the autosomal chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
s. The Yellowface Blue I mutation, the Yellowface II mutation
Yellowface II budgerigar mutation
The Yellowface II budgerigar mutation is one of approximately 30 mutations affecting the colour of budgerigars. In combination with the Blue, Opaline and Clearwing mutations, the single factor Yellowface II mutation produces the variety called Rainbow....
form an autosomal co-dominant series of alleles with the Blue mutation
.
The loci of the Dark budgerigar mutation
Dark budgerigar mutation
The Dark budgerigar mutation is one of approximately 30 mutations affecting the colour of budgerigars. It is part of the genetic constitution of the following recognised varieties: Dark Green and Olive in the green series and Cobalt, Mauve and Violet in the blue series.- Appearance :Budgerigars...
and the Blue allelic series are situated on the same autosome
Autosome
An autosome is a chromosome that is not a sex chromosome, or allosome; that is to say, there is an equal number of copies of the chromosome in males and females. For example, in humans, there are 22 pairs of autosomes. In addition to autosomes, there are sex chromosomes, to be specific: X and Y...
, so the Dark mutation is linked to the Blue allelic series (see genetic linkage
Genetic linkage
Genetic linkage is the tendency of certain loci or alleles to be inherited together. Genetic loci that are physically close to one another on the same chromosome tend to stay together during meiosis, and are thus genetically linked.-Background:...
). The cross-over value (COV) or recombination frequency between the Dark and Blue loci is commonly stated to be about 14%, but some experiments have found much smaller values (see Genetics in the Dark budgerigar mutation
Dark budgerigar mutation
The Dark budgerigar mutation is one of approximately 30 mutations affecting the colour of budgerigars. It is part of the genetic constitution of the following recognised varieties: Dark Green and Olive in the green series and Cobalt, Mauve and Violet in the blue series.- Appearance :Budgerigars...
).