Dark budgerigar mutation
Encyclopedia
The Dark 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: Dark Green and Olive in the green series and Cobalt, Mauve and Violet in the blue series.
Budgerigars carrying the Dark factor are identical to the wild-type Light Greens or Skyblues in every respect except body colour and tail feathers. The body is darker in Dark Greens and Cobalts and darker still in Olives and Mauves, and the long tail feathers are darker in proportion. All these varieties have normal violet cheek patches.
The Dark Green's body colour is a rich shade of laurel green, and Cobalt's a deep blue, approximating to royal blue
. The Olive is similar in shade to a Grey-green
, but it may be easily distinguished by its cheek patch, which is violet in the Olive and grey in the Grey-green. The Mauve is rather a dull colour, quite different from the brilliant Violet and Cobalt. In nest feather the Mauve is a shade of lavender, almost grey, but the violet cheek patch, although somewhat darker than in other varieties, identifies it as a Mauve.
The Violet Cobalt (a composite of the Blue
, Dark and Violet
mutations) is a brilliant shade of violet, rather similar but not quite as deep as and rather bluer than the wild-type violet cheek patches.
The World Budgerigar Organisation has established precise standards for certain budgerigar body colours using the Pantone
Codes, as shown to the right.
is common in the wild as Dark Green budgerigars have been observed in wild flocks on several occasions. One of the earliest to be seen was one captured during an expedition to Australia and exhibited in a London museum in 1847
.
But the Dark mutation was not seen in the domesticated budgerigar until the summer of 1915 when a Dark Green was observed by Monsieur A Blanchard in his aviaries in Toulouse
.
At the time, Toulouse was the main commercial centre for budgerigar distribution in Europe, handling thousands of imported and aviary-bred birds each year. The origins of this first Dark Green are not known. Dark Greens were known initially as Laurel Greens, a name which remained popular throughout the 1920s.
Mon. Blanchard produced the first Olives from a pair of Dark Greens in the autumn of 1916, and J D Hamlyn imported some of the early Olives to England from France in 1918.
The first Cobalts were bred by Mon. Blanchard in 1920, and by George F Hedges in 1923 while he was the aviary attendant for Madame Lecallier in France. These were initially called Powder Blues. Some of these latter Cobalts were purchased by Mrs Dalton Burgess and imported to England. She exhibited one (as a Royal Blue) in February 1924 at the Crystal Palace
and later that year bred the first Mauves from them. She called the Mauves French Greys in nest feather, and when adult they were known as Lilacs or Lavenders.
The blue forms of the Dark mutation were far more popular than the Greens and commanded fantastic prices in the mid-twenties. In February 1927 Mauves and Cobalts were sold for £175 a pair, but by 1931 the price was down to £2 a pair, as more and more were quickly bred.
relationship with its wild-type allele
. That is, it shows a visible effect when present as a single factor (heterozygote) and a different effect when present as a double factor (homozygote). In the green series varieties the Dark Green has one Dark allele and one wild-type allele at the Dark locus
and the Olive has two Dark alleles. In the blue series varieties the Cobalt has one Dark allele and one wild-type allele and the Mauve has two Dark alleles.
Because the Dark factor is always visibly expressed no budgerigar can be split for Dark. The heterozygotes of Dark — the Dark Greens and Cobalts — correspond to the splits of the recessive mutations.
The loci of the Dark 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 often stated to be about 14%, but several careful measurements of this COV show quite widely varying results. Early measurements by Duncker and independently by Steiner obtained values of 14% and 7.6% respectively, and T G Taylor and C Warner collected results which showed only 5 cross-overs in 140 - a COV of 3.6%
.
Included in these were results from T G Taylor's own experiments, in which he found no cross-overs in 86 birds bred. It is now known that the environment and other genes can influence the COV, so some variability should be expected. A reasonable average of these measurements is a COV of 8%.
Dark Green/blues have one Dark allele and one Blue allele together with one each of the corresponding wild-type alleles. The linkage between the Blue and Dark genes gives rise to two types of Dark Green/blue birds, both visually identical.
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: Dark Green and Olive in the green series and Cobalt, Mauve and Violet in the blue series.
Appearance
| Variety | Pantone Code |
|---|---|
| Light Green | 375 |
| Dark Green | 369 |
| Olive | 371 |
| Skyblue | 310 |
| Cobalt | 2915 |
| Mauve | 535 |
| Violet | 2727 |
Budgerigars carrying the Dark factor are identical to the wild-type Light Greens or Skyblues in every respect except body colour and tail feathers. The body is darker in Dark Greens and Cobalts and darker still in Olives and Mauves, and the long tail feathers are darker in proportion. All these varieties have normal violet cheek patches.
The Dark Green's body colour is a rich shade of laurel green, and Cobalt's a deep blue, approximating to royal blue
Royal blue
Royal blue describes both a bright shade and a dark shade of azure blue. It is said to have been invented by millers in Rode, Somerset, a consortium of which won a competition to make a dress for the British queen, Charlotte of Mecklenburg-Strelitz....
. The Olive is similar in shade to a Grey-green
Dominant Grey budgerigar mutation
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 :...
, but it may be easily distinguished by its cheek patch, which is violet in the Olive and grey in the Grey-green. The Mauve is rather a dull colour, quite different from the brilliant Violet and Cobalt. In nest feather the Mauve is a shade of lavender, almost grey, but the violet cheek patch, although somewhat darker than in other varieties, identifies it as a Mauve.
The Violet Cobalt (a composite of the Blue
Blue budgerigar mutation
The Blue 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: Skyblue, Cobalt, Mauve and Violet.- Appearance :...
, Dark and Violet
Violet budgerigar mutation
The violet budgerigar mutation is one of approximately 30 mutations affecting the colour of budgerigars. It is one of the constituent mutations of the violet variety.- Appearance:...
mutations) is a brilliant shade of violet, rather similar but not quite as deep as and rather bluer than the wild-type violet cheek patches.
The World Budgerigar Organisation has established precise standards for certain 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 Dark mutationis common in the wild as Dark Green budgerigars have been observed in wild flocks on several occasions. One of the earliest to be seen was one captured during an expedition to Australia and exhibited in a London museum in 1847
.
But the Dark mutation was not seen in the domesticated budgerigar until the summer of 1915 when a Dark Green was observed by Monsieur A Blanchard in his aviaries in Toulouse
Toulouse
Toulouse is a city in the Haute-Garonne department in southwestern FranceIt lies on the banks of the River Garonne, 590 km away from Paris and half-way between the Atlantic Ocean and the Mediterranean Sea...
.
At the time, Toulouse was the main commercial centre for budgerigar distribution in Europe, handling thousands of imported and aviary-bred birds each year. The origins of this first Dark Green are not known. Dark Greens were known initially as Laurel Greens, a name which remained popular throughout the 1920s.
Mon. Blanchard produced the first Olives from a pair of Dark Greens in the autumn of 1916, and J D Hamlyn imported some of the early Olives to England from France in 1918.
The first Cobalts were bred by Mon. Blanchard in 1920, and by George F Hedges in 1923 while he was the aviary attendant for Madame Lecallier in France. These were initially called Powder Blues. Some of these latter Cobalts were purchased by Mrs Dalton Burgess and imported to England. She exhibited one (as a Royal Blue) in February 1924 at the Crystal Palace
The Crystal Palace
The Crystal Palace was a cast-iron and glass building originally erected in Hyde Park, London, England, to house the Great Exhibition of 1851. More than 14,000 exhibitors from around the world gathered in the Palace's of exhibition space to display examples of the latest technology developed in...
and later that year bred the first Mauves from them. She called the Mauves French Greys in nest feather, and when adult they were known as Lilacs or Lavenders.
The blue forms of the Dark mutation were far more popular than the Greens and commanded fantastic prices in the mid-twenties. In February 1927 Mauves and Cobalts were sold for £175 a pair, but by 1931 the price was down to £2 a pair, as more and more were quickly bred.
Genetics
The Dark mutation has an incompletely dominantDominance relationship
Dominance in genetics is a relationship between two variant forms of a single gene, in which one allele masks the effect of the other in influencing some trait. In the simplest case, if a gene exists in two allelic forms , three combinations of alleles are possible: AA, AB, and BB...
relationship with its wild-type allele
Allele
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...
. That is, it shows a visible effect when present as a single factor (heterozygote) and a different effect when present as a double factor (homozygote). In the green series varieties the Dark Green has one Dark allele and one wild-type allele at the Dark 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...
and the Olive has two Dark alleles. In the blue series varieties the Cobalt has one Dark allele and one wild-type allele and the Mauve has two Dark alleles.
Because the Dark factor is always visibly expressed no budgerigar can be split for Dark. The heterozygotes of Dark — the Dark Greens and Cobalts — correspond to the splits of the recessive mutations.
The loci of the Dark mutation 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 often stated to be about 14%, but several careful measurements of this COV show quite widely varying results. Early measurements by Duncker and independently by Steiner obtained values of 14% and 7.6% respectively, and T G Taylor and C Warner collected results which showed only 5 cross-overs in 140 - a COV of 3.6%
.
Included in these were results from T G Taylor's own experiments, in which he found no cross-overs in 86 birds bred. It is now known that the environment and other genes can influence the COV, so some variability should be expected. A reasonable average of these measurements is a COV of 8%.
Dark Green/blues have one Dark allele and one Blue allele together with one each of the corresponding wild-type alleles. The linkage between the Blue and Dark genes gives rise to two types of Dark Green/blue birds, both visually identical.
- Type I Dark Green/blues are bred by mating Mauves to Light Greens and have the two mutant alleles on the same chromatidChromatidA chromatid is one of the two identical copies of DNA making up a duplicated chromosome, which are joined at their centromeres, for the process of cell division . They are called sister chromatids so long as they are joined by the centromeres...
. Geneticists call this 'couplingGenetic linkageGenetic 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:...
' rather than 'Type I'. Because of the linkage, the Dark and Blue alleles from Type I birds tend to be inherited together in their progeny. When mated to Skyblues, Type I birds produce predominantly Light Green/blue and Cobalt progeny, with Dark Green/blue Type II and Skyblues resulting rarely from a cross-over.
- Type II Dark Green/blues are bred by mating Skyblues to Olives and have the Dark and Blue mutant alleles on opposite chromatids. Geneticists call this 'repulsionGenetic linkageGenetic 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:...
' rather than 'Type II'. Because of the separation, the Dark and Blue alleles from Type II birds tend to be inherited separately in their progeny. When mated to Skyblues, Type II birds produce predominantly Dark Green/blue Type II and Skyblue progeny, with Light Green/blue and Cobalts resulting rarely from cross-overs.