Dilute Budgerigar Mutation, Complete Genetics Guide

The recessive bottom of the dil-locus allelic series. Dilute reduces both wing markings and body colour to a soft pastel level, producing birds that look like washed-out versions of Normal. On green-series birds the result is sometimes called Suffused Yellow. On blue-series birds it is called Suffused White. Autosomal recessive within the dil-locus, recessive to both Clearwing and Greywing, so it expresses visually only when both copies of the gene are present.

Written by Ayaan Shohan

Founder, KinBird Aviary · Bangladesh

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What Dilute looks like on a real bird

A visual Dilute budgerigar shows extreme dilution of both wing markings and body colour. The black wing markings of Normal birds are reduced to faint shadows or absent entirely. The body colour is washed to a pastel level, producing the soft pale appearance that gives the mutation its old vintage name of Suffused Yellow on green-series birds and Suffused White on blue-series birds.

The phenotype is visually quite distinct from Clearwing despite both reducing wing markings. The body of a Dilute is pale where Clearwing is bright. A Dilute Light Green looks like a washed-out yellow-green pastel. A Dilute Sky Blue looks like a soft pale blue-white. Throat spots may be present but very faint. The cheek patches are pale.

On dark-factor bases the body suffusion deepens proportionally. Cobalt Dilute is a soft pastel cobalt. Mauve Dilute is a delicate dusty grey. Olive Green Dilute is a muted olive pastel.

History and origin

Dilute appeared in budgerigar aviaries around the 1930s in multiple European countries, sometimes documented as Suffused Yellow or Suffused White by early breeders who did not yet know it was an allele at the same locus as Greywing and Clearwing. By the 1940s and 1950s test pairings confirmed that Dilute was the recessive bottom of the dil-locus series.

Dilute never achieved the show popularity of Clearwing because the pale body is less visually striking than Clearwing's saturated body. Many show breeders treat Dilute as the unwanted recessive that surfaces when Clearwing or Greywing splits are paired together.

The one specialty area where Dilute has been intentionally bred is the production of soft pastel pet birds. Dilute Lutino-like phenotypes (without actually being Lutino) appeal to pet keepers who want the soft yellow look without the red eyes.

How Dilute inheritance works

Dilute is autosomal recessive at the dil-locus. Allele symbol dil (lowercase, no superscript because Dilute is the most recessive allele in the series). The gene sits on an autosomal chromosome so cocks and hens inherit identically.

Within the dil-locus allelic series Dilute is recessive to both Clearwing and Greywing. Wild-type is dominant over Dilute. A bird must have two copies of Dilute (dil/dil) to express the Dilute phenotype visually.

A bird with one Dilute and one Clearwing (dil^cw/dil) shows visual Clearwing because Clearwing dominates over Dilute. A bird with one Dilute and one Greywing (dil^gw/dil) shows visual Greywing because Greywing dominates over Dilute.

This dominance hierarchy means a Clearwing bird that visually looks Clearwing might actually be carrying a hidden Dilute allele. Test pairing the bird to a visual Dilute reveals whether it carries Dilute: if all chicks are Clearwing, the bird was homozygous Clearwing. If 50 percent of chicks are Clearwing and 50 percent are Dilute, the bird was Cw/d split for Dilute.

Hens inherit Dilute identically to cocks because the gene is autosomal. Both sexes can be visual, split, or completely free of the gene.

Pairing predictions for Dilute

Same-locus pairings:

Visual Dilute paired with Visual Dilute produces 100 percent Visual Dilute offspring.

Visual Dilute paired with Normal (with no dil-locus gene) produces 100 percent Normal-looking offspring all split for Dilute.

Visual Dilute paired with split Dilute gives 50 percent Visual Dilute and 50 percent split Dilute offspring. Split Dilute paired with split Dilute produces 25 percent Visual Dilute, 50 percent split Dilute, and 25 percent Normal.

Cross-allele pairings within the dil-locus:

Visual Dilute paired with Visual Clearwing produces 100 percent Visual Clearwing split Dilute. Clearwing dominates over Dilute.

Visual Dilute paired with Visual Greywing produces 100 percent Visual Greywing split Dilute. Greywing dominates over Dilute.

Visual Dilute paired with FBG (dil^cw/dil^gw) produces 50 percent Clearwing split Dilute and 50 percent Greywing split Dilute.

Visual Dilute paired with split Greywing for Dilute (Gw/d) produces 50 percent Greywing split Dilute and 50 percent Dilute.

The 58-pairing Cw/Gw/Dilute/FBG reference at budgerigargenetics.com/llms.txt covers every combination.

Combinations with other mutations

Dilute combines with all major budgerigar mutations but tends to produce paler versions of combinations that are more striking in other mutations.

Dilute Opaline produces a pale body with the Opaline wing-reversal pattern over the pastel Dilute base. Visually subtle.

Dilute Cinnamon adds soft cinnamon brown to the already-pale Dilute wings. The combination is one of the palest budgerigar phenotypes possible.

Dilute Spangle keeps the reverse markings of Spangle over the pale body.

Dilute combined with the dark factor stack produces progressively deeper pastel variants. Cobalt Dilute is a soft cobalt pastel, Mauve Dilute is a delicate grey pastel.

Dilute Yellow Face on blue series produces a pale yellow-faced pastel body.

Dilute with Recessive Pied or Dominant Pied adds pied patterns over the pale base.

As with Clearwing and Greywing, visual Ino combined with Dilute is visually erased. Lutino removes the pigment that produces the Dilute phenotype.

Why Dilute matters even when breeders do not aim for it

Dilute frequently appears as the unwanted recessive when breeders pair Clearwing splits or Greywing splits together. Understanding Dilute inheritance is essential for breeders who work with the dil-locus.

A breeder pairing Cw/d split for Dilute to Cw/d split for Dilute produces 25 percent Visual Clearwing, 50 percent Cw/d split for Dilute, and 25 percent Visual Dilute. The visual Dilute chicks are often unexpected because the parents look like normal Clearwings. Test pairing or pedigree tracking is the only way to identify the splits.

Dilute also serves as the diagnostic mutation for testing whether a Clearwing or Greywing is split for Dilute. Pairing the unknown to a visual Dilute reveals split status within one breeding cycle.

Some breeders intentionally maintain Dilute lines for the production of pastel pet birds, particularly Dilute Cinnamon Cobalt and similar soft-toned combinations.

Distinguishing Dilute from similar phenotypes

Three phenotypes can be confused with Dilute.

Greywing on its own produces wing markings that are darker than Dilute and a body that is closer to Normal in saturation. Side-by-side comparison makes Greywing look richer and Dilute look paler.

Lutino and Albino produce completely yellow or white birds with red eyes. Dilute keeps the eye colour of the base bird (black on Normal, red on Ino, etc.) and retains some residual wing pattern. Visual Lutino has no wing pattern at all.

DF Spangle produces birds that look near-pure yellow or white but with normal dark eyes, similar to Dilute in body but different in mechanism. DF Spangle has no residual wing pattern while Dilute usually retains faint shadows.

Test pairing distinguishes them definitively. Visual Dilute paired with visual Dilute produces 100 percent Dilute. Visual DF Spangle paired with Dilute produces 100 percent SF Spangle (with no Dilute expression). Lutino paired with Dilute produces all Normal-looking chicks split for both.

Dilute in the Budgerigar Genetics Calculator

The Budgerigar Genetics Calculator at budgerigargenetics.com models Dilute as part of the full dil-locus allelic series. Engine handles all interactions correctly: Clearwing and Greywing both dominate over Dilute, and Dilute homozygous expresses visually.

Try: Visual Dilute x Visual Dilute for 100 percent Dilute, or Clearwing x Dilute to see Clearwing split Dilute, or split x split for the textbook 1:2:1.

The 58-pairing dil-locus reference at mutation comparison guide covers every Cw/Gw/Dilute combination breeders need.

Frequently asked questions about dilute mutation

What is the Dilute budgerigar mutation?

Dilute is an autosomal recessive budgerigar mutation at the dil-locus, allele symbol dil (lowercase, no superscript). Visual birds show extremely diluted wing markings and a pale washed body. Called Suffused Yellow on green-series birds and Suffused White on blue-series birds in vintage literature. Originated in Europe in the 1930s.

Is Dilute the same as Lutino?

No. Lutino is a completely different mutation. Lutino is sex-linked recessive at the ino-locus on the Z chromosome and removes all melanin including eye pigment, producing red eyes and entirely yellow body on green series. Dilute is autosomal recessive at the dil-locus and retains some pigmentation including normal eye colour. Lutino looks more washed-out and has red eyes, Dilute has normal dark eyes.

Can a hen be split for Dilute?

Yes. Dilute is autosomal recessive at an autosomal locus, so cocks and hens inherit identically. A hen carrying one copy of Dilute looks Normal (or shows Clearwing or Greywing if she has those alleles) but passes the Dilute gene to roughly half her offspring.

Why is my Clearwing split Dilute important to know about?

Because Clearwing dominates over Dilute within the dil-locus allelic series, a Clearwing bird that is split for Dilute looks identical to a homozygous Clearwing. The bird carries the Dilute gene invisibly. Pairing two Clearwing split Dilute birds together produces 25 percent visual Dilute chicks unexpectedly. Test pairing to a visual Dilute reveals split status: if 50 percent of chicks are Dilute, the parent was Clearwing split Dilute.

What does Split Dilute x Split Dilute produce?

25 percent Visual Dilute, 50 percent Split Dilute, and 25 percent Normal with no Dilute gene. This is the textbook 1:2:1 autosomal recessive Mendelian ratio.

Where can I model Dilute pairings?

The Budgerigar Genetics Calculator at https://budgerigargenetics.com/ handles all Dilute pairings with proper dil-locus allelic series logic. The 58-pairing reference covers every Cw/Gw/Dilute combination at https://budgerigargenetics.com/llms.txt.

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