Budgerigar colour genetics

The science of budgerigar color genetics deals with the heredity of mutations which cause color variation in the feathers of the species known scientifically as Melopsittacus undulatus. Birds of this species are commonly known by the terms 'budgerigar', or informally just 'budgie'.

Melopsittacus undulatus at Chai-Negev, Revivim, Israel.

Background

The wildtype (natural-coloured or wild occurring) budgerigar's color is called Lightgreen. The feathers of most parrot species, including budgerigars, contain both a black type of melanin named eumelanin along with a basic yellow pigment named psittacofulvin (psittacin for short). Some other parrot species produces a third pigment named advanced-psittacin which enables color & tones ranging from oranges, peaches, pinks to reds. When these feathers are exposed to a white light source, such as sunlight, only the blue part of the spectrum is reflected by the eumelanin granules. This reflected blue light passes through the yellow pigment layer, resulting in the green colouration known as lightgreen in only the budgerigar and/or green in any other naturally green coloured parrot species.

The many color variations of budgerigars, such as albino, blue, cinnamon, Clearwinged, the various Fallows, Grey, Greygreen, Greywing, Lutino, Mauve, Olive, Opaline, Spangled, Suffused and Violet are the result of mutations that have occurred within specific genes. There are actually at least thirty-two known primary mutations established among budgerigars. These can combine to form hundreds of secondary mutations and color varieties which may or may not be stable.

As is true with all animal species, color mutations occur in captivity as do in the wild. This has been demonstrated when captive-bred budgerigars have developed mutations that had only been previously recorded amongst wild populations.

Classification of mutations

Basic groups

Each of the thirty-two primary mutations belong to one of the four basic groups of mutations classified in parrot species genetics:

Because of albinism this budgerigar has virtually no eumelanin pigment. This, together with the Blue mutation which removes the yellow pigmentation, produces a nearly pure white colouration along with clear (orange) beak, pink feet/skin, white-tipped clear (pink) toe nails and red eyes.

Dominance relationship

These mutations are inherited through one of the following dominance relationships.

  • autosomal-Co-Dominant (A-Co-D),
  • autosomal-Complete-Dominant (A-C-D),
  • autosomal-Incomplete-Dominant (A-I-D),
  • autosomal-recessive (A-R),
  • autosomal-Poly-Genic (A-P-G)
  • Sex-Linked-recessive (S-L-R)

Table of primary mutations
Mutation(s) Common names & varieties Type Wild-type symbol (Locus) Allele Symbol Dominance Relationship
Dark D Green (Dark Green), D_Blue (Cobalt), DD Green (Olive) & DD_Blue (Mauve) Structural D+ D A-I-D
Blue 1 Blue-series color b+ b1 recessive with other b-locus alleles except b2, else A-R
Blue 2 Blue-series color b+ b2 recessive with other b-locus alleles except b1, else A-R
Blue 1-Blue 2 Yellowface I color b+ b1 / b2 (Hetero-allelic mutation produced by crossing Blue 1 & Blue 2 varieties)
Yellowface Yellowface II color b+ byf Dominant with other b-locus alleles except gf , else A-R
Goldenface Goldenface color b+ bgf Dominant with other b-locus alleles, else A-R
Crest-Factor (C-F) Circular Crested, Semicircular Crested & Tufted Structural Cr+ Cr A-P-G
Dominant Grey (Australian) Grey & Greygreen Structural G+ G A-C-D
English Grey English Grey & Greygreen Structural g+ g A-I-D (rare or extinct)
Anthracite Anthracite Structural An+ An A-I-D (rare)
Recessive Grey & Greygreen Australian recessive greygreen & grey Structural rg+ rg A-R (extremely rare or extinct)
Slate Slate (bluish-gray) Structural sl+ sl S-L-R
Violet SF Violet (SF Violet Green), SF Violet Blue (Violet Skyblue), DF Violet Green (pure Violet Green) & DF Violet Blue (pure VIOLET), SF Violet D_Blue (show Violet), DF Violet D_Blue (VIOLET Mauve) Structural V+ V A-I-D
Dilute Suffused Green (Dilute Yellow) and Suffused Blue (Dilute White) Dilution dil+ dils A-R
Clearwing (CW) Clearwing Green (Yellowing) & Clearwing Blue (Whitewing) Dilution dil+ dilcw A-Co-D with dilgw allele,
A-D over dild allele, else A-R
Greywing (GW) Greywing Green & Greywing Blue, Dilution dil+ dilgw A-Co-D with dilcw allele,
A-D over dild allele, else A-R
Greywing-Clearwing Fullbodied-Greywing Green & Fullbodied-Greywing Blue Dilution dil+ dilcw / dilgw (Hetero-allelic mutation produced by crossing Clearwing & Greywing varieties)
ADMpied a.k.a. Recessivepied Anti Dimorphic Pied, Danishpied, Harlequin, Local-Leucism s+ s A-R
Piebald Australian Pied Australian Pied, Banded Pied Local-Leucism Pb+ Pb A-C-D
Piednape Continental_Dutchpied & Clearflighted_Dutchpied Local-Leucism Pi+ Pi A-C-D
Clear-Pied Black-Eyed-Clear (a.k.a. Dark-Eyed-Clear) Total Leucism Pi+ ; s+ Pi / s A-Co-D Clear Yellow & White morphs produced by combining SF &/or DF Clearflighted_Dutchpied with Homozygous ADMpied a.k.a. Recessivepied
Spangle-Factor (Sp) SF Spangled (showtype / typical mutation) & DF Spangled (clear white &/or clear yellow pure mutation) Total Leucism Sp+ Sp A-I-D
NSLino Non-Sex-Linked Ino a.k.a. Recessive Ino NSL Complete Albinism a+ a*a A-R (extremely rare or extinct)
Bronzefallow German Fallow NSL Incomplete Albinism a+ abz A-R
Brown &/or Sepia Brownwinged NSL Incomplete Albinism b+ b Presumed A-Co-D with only a-Locus alleles, else exclusively/inclusively A-R (extremely rare or extinct)
Faded   NSL Incomplete Albinism fd+ fd A-R (extremely rare)
Palefallow Australianfallow. Beigefallow, Palebrownfallow NSL Incomplete Albinism pf+ pf A-R
Dunfallow English Fallow NSL Incomplete Albinism df+ df A-R
Scottish Fallow
(a.k.a. Plumeyed Fallow)		 Scottish Fallow NSL Incomplete Albinism pl+ pl A-R
Cinnamon Cinnamon SL Incomplete Albinism cin+ cin S-L-R
Ino Albino, Lutino SL Complete Albinism ino+ ino S-L-R
Cinnamon-Ino Lacewing SL Incomplete Albinism cin+ ; ino+ cin / ino S-L-R cross-over (3% frequency) between Cinnamon & Ino Loci
Sex-linked Clearbody Texas Clearbody Partial-Albinistic (Par-ino) ino+ inocl SL-Co-D with other ino locus alleles, else S-L-R
Blackfaced (BF)   Melanism bf+ bf A-R
Darkwinged (DW)   Modifier dw+ dw A-Co-D (only noticeably expressive in combination with dil-Locus alleles and with Greywinged & Suffused)
Dominant Clearbody Easley Clearbody Pigment redistributing Cl+ Cl A-C-D
Opaline Opaline Pigment redistributing op+ op S-L-R
Saddlebacked (SB)   Local-Leucism sb+ sb A-R (extremely rare or extinct)

History

In the first few decades of the 1900s, especially in-between World War I and II, the keeping and breeding of the budgerigar had become very popular all around the world. Consequently, various mutations occurred and were soon established during this period.

Timeline
  • 1870–75 The very first registered sudden captive-bred color mutations were Suffused Green (a.k.a. Dilute Yellow), Greywinged Green and either one of the two types of Lutino (NSLino &/or SLino) mutations. All three occurred in aviaries in Great Britain or Europe. Of these three mutations, only the Suffused Green (a.k.a. Dilute Yellow) has survived. The latter was easily reproduced in great numbers and is nowadays very well established. The first Lutino mutation quickly vanished but it was re-established in Europe some time between 1931 and 1933.
  • 1878–85 The Skyblue mutation suddenly occurred in continental Europe, most probably in Uccle, Belgium. Surprisingly, this variety was not imported in England until 1910.
  • 1915 Single-Factored Dark-Green (a.k.a. Dark-Green) in France (where they were then commonly called 'Laurel' which is the French word for Bay (leaf &/or tree))
  • 1916 Double-Factored Dark-Green (a.k.a. Olive) in France.
  • 1918–28 Respectively, Greywinged Green and Greywinged Blue appeared in England and continental Europe.
  • 1920
    • Crest-Factor in Australia.
    • Suffused Blue (a.k.a. Dilute White) in England and France.
    • Single-Factored Dark_Blue (a.k.a. Cobalt) in France.
  • 1921 Double-Factored Dark_Blue (a.k.a. Mauve) in France.
  • 1930
    • Single-Factored Violet-Green (a.k.a. Violet Factor) in Australia (and were then 1st commonly called 'Satin Green')
    • The first Clearwinged Green (Yellowinged) appeared, developed by H. Pier in Sydney.
  • 1931
    • Cinnamon in England, Australia & Germany.
    • An unknown type of Fallow in California, U.S. This soon vanished.
    • The Germanfallow in Germany, recently been genetically classified and identified as the Bronzefallow (a.k.a. Brownfallow).
    • A plum-eyed mutation, similar looking to Fallow mutations, occurred in England. This vanished or at least became very rare. This mutation was most probably the Brownwings, one of the rarest color mutations of the species.
    • The first Albino specimens were produced in both England and continental Europe.
  • 1932
    • Three Fallow mutations occurred in England which became known as the Englishfallow. In Australia these have been genetically classified and identified as the Dunfallow or Greybrownfallow (a.k.a. Australianfallow). The Beigefallow or Palebrownfallow has been classified in South-Africa, but no reference seems to be available on this particular mutation.
    • The recessive Anti-dimorphic Pied (a.k.a. Danish Pied a.k.a. Harlequin) in Denmark.
    • The Australian (a.k.a. Banded) Pied in Australia.
  • 1933
    • Green Clearwinged (a.k.a. Yellow Wing) and Dominant Grey-Factor appear in Australia.
    • Both the NSL & the SL Lutino gene occurred in England and continental Europe.
    • Three Opaline mutations occurred. An Opaline Green hen was captured in the wild and sold to S. Terril in Adelaide. It was later-on reproduced and is most probably the ancestor of all Opaline specimens in Australia. Two sudden captive-bred Opaline mutations occurred in England and the Netherlands.
  • 1934 Recessive grey factor in England.
  • 1935 The various Yellowfaced_Blue and Goldenfaced_Blue occurred in several locations.
  • 1939–46 Clearflighted_Dutchpied in Belgium.
  • 1948
    • Texas Clearbodied (a.k.a. SL-Clearbody) in the U.S.
    • Dominant Clearbodied (a.k.a. Easley's Clearbodied) in the U.S.
    • The first Cinnamon-Ino (a.k.a. Lacewings) cross-over mutation was produced in Australia.
    • The first Dark-Eyed-Clear (DEC) variety was produced in Belgium by combining the ADM Pied (a.k.a. Danish/Recessive pied) with either one of the two Dutchpied varieties (Continental or Clearflighted).
  • 1970–74 Single-Factored and Double-Factored Spangled specimens were produced in Australia.
  • 1975 Saddleback specimens were produced in Australia.
  • 1992 Blackface specimens make their first appearance in the Netherlands.
  • 2010 White Cap bred in Australia. These birds have a yellow face, but with a white cap.

Notes

It is possible that the Greywings mutation survived as the ancestor of all actual Greywings. However, it could be that the mutation lay dormant in asymptomatic mutant specimens until it was re-established between 1918 and 1925. Blue Greywing specimens were produced later on in 1928.

It is possible that all Suffused mutation specimens and their varieties are descendants from the first captive mutant specimens. This would mean that Suffused is the oldest sudden captive-bred color mutation of the Budgerigar species.

gollark: PoE is relatively non-awful, since catwhatever cables are actually designed for carrying data signals.
gollark: PoE is power over ethernet lines. EoP is ethernet over power lines.
gollark: Not PoE, EoP.
gollark: Relatedly, ethernet over power is awful.
gollark: I just have no wireless card.

References
    • Martin, Terry (2002). A Guide To Colour Mutations and Genetics in Parrots. ABK Publications. ISBN 0-9577024-6-9.
    • Hayward, Jim (1992). The Manual of Colour Breeding. The Aviculturist Publications. ISBN 0-9519098-0-0.
    This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.