Information about Budgerigar Colour Genetics

The science of Budgerigar colour genetics deals with the heredity of colour variation in the feathers of the species known as Melopsittacus undulatus, commonly known as the 'Budgerigar Parakeet' or 'Budgie' for short.

Background

The basic colour of the wild Budgerigar is light-green. 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 colours & tones ranging from oranges, 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 Light Green in only the Budgerigar Parakeet &/or Green in any other naturally green coloured Parrot species.

The many colour variations of Budgerigars, such as albino, blue, grey, grey-green, lutino, mauve, olive, violet, yellow, white... are the result of mutations that have occurred within specific genes. There are at least thirty-two known primary mutations that can influence Budgerigar colour. These can combine to form hundreds of secondary mutations, which may or may not be stable.

As is true with all animal species, colour 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;

• Albinism : where eumelanin is either partially or completely reduced in all body tissues & structures.
• Dilution : where eumelanin is partially reduced in only feathering.
• Leucism : where eumelanin is completely reduced from total or localized feathering.
• Melanism : where eumelanin is increased in the feathering.

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

Name	Common name	Type	Allele/Locus	Inheritance
Dark-Factor		Blue Loci	D-Locus	A-Co-D when only Blue Loci alleles, else exclusively/additionally A-I-D
Blue		Blue Loci	bl*bl	A-Co-D when only Blue Loci alleles, else exclusively/additionally A-R
BlueII		Blue Loci	blII-Locus	A-Co-D when only Blue Loci alleles, else exclusively/additionally A-R
Yellowfaced_Blue		Blue Loci	blII*yf	A-Co-D when only Blue Loci alleles, else exclusively/inclusively A-R
Goldenfaced_Blue		Blue Loci	blII*gf	A-Co-D when only Blue Loci alleles, else exclusively/inclusively A-R
Crest-Factor		Structural	Cr-Locus	A-P-G
Dark-Factor		Structural	D-Locus	A-I-D
Grey-Factor	Dominant Grey Factor	Structural	G-Locus	A-C-D
Grey-Factor	English Recessive Grey Factor	Structural	g-Locus	A-R (extremely rare or extinct)
Grey-Factor	Australian Recessive Grey Factor	Structural	ag-Locus	A-R (extremely rare or extinct)
Violet-Factor		Structural	V-Locus	A-I-D
Suffused	Dilute	Dilutistic	dil*dil	A-Co-D when only dil-Locus alleles, else exclusively/inclusively A-R
Clearwing		Dilutistic	dil*cw	A-Co-D when only dil-Locus alleles, else exclusively/inclusively A-R
Greywing		Dilutistic	dil*gw	A-Co-D when only dil-Locus alleles, else exclusively/inclusively A-R
Anti-dimorphic (ADM) Pied	Danishpied, Recessivepied, Harlequin	Local-Leucistic	s-Locus	A-R
Piebald	Australianpied or Bandedpied	Local-Leucistic	Pb-Locus	A-C-D
Piednape	Continental_Dutchpied, Clearflighted_Dutchpied	Local-Leucistic	Pi-Locus	A-C-D
Spangle-Factor		Total Leucistic	Sp-Locus	A-I-D
Clearpied aka Dark-eyed-Clear		Total Leucistic	dil*cw / dil*gw	A-Co-D (not a genuine primary mutation, it is produced by visually combining ADMpied with either Continental or Clearflighted_Dutchpied varieties)
NSL Albinism	Recessive Albinism	Albinistic	a-Locus
NSL-ino	Recessive-Ino	Albinistic	a*a	A-R (extremely rare or extinct)
Bronzefallow	Germanfallow	Albinistic	a*bz	A-Co-D when only a-Locus alleles, else exclusively/inclusively A-R
Brown, Brownwings	Sepia	Albinistic	b-Locus	Presumed A-Co-D when only a-Locus alleles, else exclusively/inclusively A-R (extremely rare or extinct)
Cinnamon	Cinnamonwings	Albinistic	cin-Locus	S-L-R
Dunfallow, Greybrownfallow	Englishfallow	Albinistic	df-Locus	A-R
Faded		Albinistic	fd-Locus	A-R (extremely rare or extinct)
Beigefallow, Palebrownfallow	Australianfallow	Albinistic	pF-Locus	A-R (possible)
Plumeyedfallow	Scottishfallow	Albinistic	pl-Locus	A-R (possible)
SL-Albinism		Albinistic	ino-Locus
SL-ino		Albinistic	ino-Locus	S-L-R
SL-Clearbody		Albinistic	ino*cl	SL-Co-D when only ino-Locus alleles, else exclusively/inclusively S-L-R
Blackface		Melanism	bf-Locus	A-R
Darkwings		Other	dw-Locus	A-I-D (extremely rare or extinct)
Dominant-Clearbody		Other	Cl-Locus	A-C-D
Opaline		Other	op-Locus	S-L-R
Saddleback		Other	sb-Locus	A-R (extremely rare or extinct)
Slate		Other	sl-Locus	S-L-R

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.

Time line

• 1870-75 The very first registered sudden captive-bred colour mutations were Green Suffused (aka Dilute Green), Green Greywings and either one of the two types of Lutino (NSL-Ino &/or SL-Ino) mutations. All three occurred in aviaries in Great Britain or Europe. Of these three mutations, only the Suffused Green (aka 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 The first Sky Blue Budgerigar appeared in Belgium.
• 1880-85 The Blue 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 (aka Dark-Green) in France.
• 1916 Double-Factored Dark-Green (aka Olive) in France.
• 1918-25 Greywings Green and Greywings Blue appeared in England and continental Europe.
• 1920
• Crest-Factor in Australia.
• Suffused Blue (aka Dilute White) in England and France.
• Single-Factored Dark_Blue (aka Cobalt) in France.
• 1921 Double-Factored Dark_Blue (aka Mauve) in France.
• 1930
• Single-Factored Violet-Green (aka Violet Factor) in Australia.
• The first Clearwing appeared, developed by H. Pier in Sydney.
• 1931
• Cinnamon in England, Australia & Germany.
• An unknown type of Fallow in California, U.S.A. This soon vanished.
• The Germanfallow in Germany, recently been genetically classified and identified as the Bronzefallow (aka 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 colour 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 (aka Australianfallow). The Beigefallow or Palebrownfallow has been classified in South-Africa, but no reference seems to be available on this particular mutation.
• A the recessive Anti-dimorphic Pied (aka Danish Pied) in Denmark.
• A Dominant Pied (aka Australian Pied) in Australia.
• 1933
• Green Clearwing (aka 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 Holland.
• 1934 Recessivegrey factor in England.
• 1935 The Yellowfaced_Blue and Goldenfaced_Blue occurred in several locations.
• 1939-46 Clearflighted_Dutchpied in Belgium.
• 1948
• Texas Clearbody (aka SL-Clearbody) in the U.S.A.
• Dominant Clearbody in the U.S.A.
• The first Cinnamon-Ino crossover (aka Lacewings) mutation was produced in Australia.
• The first Dark Eyed Clear variety was produced in Belgium by combining the ADM Pied (aka 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.

Notes

It is probable that the Greywings mutation survived as the ancestor of all actual Greywings. However, it is possible that the mutation laid 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 very likely that all Suffused mutation specimens and their varieties are descendants from the first captive mutant specimens. This means that Suffused is the oldest sudden captive-bred colour mutation of the Budgerigar species.

References

External links

• Martin Rasek's Budgerigar Genetic calculator
• Inte ONSMAN's MUTAVI Research and Advice Group
• Clive Hesford's The Genetics of Colour in the Budgerigar and other Parrots website
• World Budgerigar Orginization's Colour Standards
• Down Under Aviary's Genetics page
• Budgerigar Galore's Genetics Articles