![Melopsittacus undulatus -blue -pet-8](https://upload.wikimedia.org/wikipedia/commons/a/a6/Melopsittacus_undulatus_-blue_-pet-8.jpg)
The Blue budgerigar mutation is one of approximately 30 mutations affecting the colour of
budgerigar
The budgerigar ( ; ''Melopsittacus undulatus''), also known as the common parakeet or shell parakeet, is a small, long-tailed, seed-eating parrot usually nicknamed the budgie ( ), or in American English, the parakeet. Budgies are the only spe ...
s. It is part of the genetic constitution of the following recognised varieties: Skyblue, Cobalt, Mauve and Violet.
Appearance
![Melopsittacus undulatus male](https://upload.wikimedia.org/wikipedia/commons/b/b3/Melopsittacus_undulatus_male.jpg)
The Blue
mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...
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
A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...
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
Cortex or cortical may refer to:
Biology
* Cortex (anatomy), the outermost layer of an organ
** Cerebral cortex, the outer layer of the vertebrate cerebrum, part of which is the ''forebrain''
*** Motor cortex, the regions of the cerebral cortex i ...
) 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
Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tail ...
. 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
In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...
.
Parrot feathers contain red, orange, and yellow polyene pigments called psittacofulvins. Genome-wide association mapping and gene-expression analysis mapped the Mendelian blue locus, which abolishes yellow pigmentation in the budgerigar. The blue trait maps to a single amino acid substitution (R644W) in an uncharacterized polyketide synthase (MuPKS) gene. When the MuPKS gene is expressed in yeast, yellow pigments accumulated. Mass spectrometry confirmed the yellow pigments matched those in feathers. The R644W substitution abolished MuPKS gene activity. Furthermore, gene-expression data from feathers of different bird species suggest that parrots acquired their colors through regulatory changes that drive high expression of the MuPKS gene in feather epithelia. This formulates biochemical models that explain natural color variation in parrots.
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 Organization 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 Blue mutation
made its first recorded appearance in 1878
[Watmough (1951), p 14] in the aviaries of M Limbosch of
Uccle
Uccle () or Ukkel () is one of the 19 municipalities of the Brussels-Capital Region, Belgium. In common with all of Brussels' municipalities, it is legally bilingual (French–Dutch). It is generally considered an affluent area of the city a ...
, a suburb of
Brussels
Brussels (french: Bruxelles or ; nl, Brussel ), officially the Brussels-Capital Region (All text and all but one graphic show the English name as Brussels-Capital Region.) (french: link=no, Région de Bruxelles-Capitale; nl, link=no, Bruss ...
, but this strain died out, it is believed, in 1881. Blues appeared independently in the
Netherlands
)
, anthem = ( en, "William of Nassau")
, image_map =
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Kingdom of the Netherlands
, established_title = Before independence
, established_date = Spanish Netherl ...
between 1881 and 1885, and a Mr Pauwels of
Everberg
Everberg is a town in the Belgian province Flemish Brabant and is part of the municipality of Kortenberg. The territory covers an area of 925 ha. The neighbouring towns or municipalities are Leefdaal, Kortenberg, Erps-Kwerps, Meerbeek, Sterreb ...
, near Brussels, reintroduced them to
Belgium
Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...
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 () is a district of southwest London, England, in the London Borough of Wandsworth, southwest of Charing Cross. The area is identified in the London Plan as one of 35 major centres in Greater London.
History
Putney is an ancient paris ...
bred a Blue in 1912.
Blues remained quite rare until the 1930s, fetching up to £100 per pair in
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
around 1928, about the cost of a car at the time.
Genetics
The Blue mutation is recessive to its wild-type
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 ...
, so a bird possessing a single Blue 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 ...
) 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
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 ...
), 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 (plural loci) is Latin for "place". It may refer to:
Entertainment
* Locus (comics), a Marvel Comics mutant villainess, a member of the Mutant Liberation Front
* ''Locus'' (magazine), science fiction and fantasy magazine
** ''Locus Award' ...
of the Blue gene is situated on one of the
autosomal
An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology, unlike those in allosome, allosomal (sex chromosome) pairs, which may have different structures. The DNA in au ...
chromosome
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 ...
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
An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology, unlike those in allosome, allosomal (sex chromosome) pairs, which may have different structures. The DNA in au ...
, so the Dark mutation is linked to the Blue allelic series (see
genetic linkage
Genetic linkage is the tendency of DNA sequences that are close together on a chromosome to be inherited together during the meiosis phase of sexual reproduction. Two genetic markers that are physically near to each other are unlikely to be separ ...
). The cross-over value (COV) or
recombination frequency
Genetic linkage is the tendency of DNA sequences that are close together on a chromosome to be inherited together during the meiosis phase of sexual reproduction. Two genetic markers that are physically near to each other are unlikely to be separ ...
between the Dark and Blue loci is commonly stated to be about 14%,
[Taylor and Warner (1986), p 31] but some experiments have found much smaller values (see
Genetics
Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar wor ...
in the
Dark budgerigar mutation).
Notes
References
*
*
External links
World Budgerigar Organisation (WBO)
{{Budgerigar mutations
Budgerigar colour mutations