The Dominant Clearbody budgerigar mutation is one of approximately 30 mutations affecting the colour of budgerigars. It is the underlying mutation of the Easley Clearbody variety.
Contents
Over the years many mutations have been reported which produce a (relatively) clear yellow or white body with normal black or dark wing markings, approximating to the beautiful painting of a (hypothetical) "laced Yellow" by R A Vowles shown in Dr M D S Armour's book, "Exhibition Budgerigars". In an article published in Cage and Aviary Birds Dr T Daniels summarised those that were known in 1981. Many of these failed to become established, and others, reported separately, may have been the same mutation which appeared in different parts of the world. The Dominant Clearbody was one which was established successfully, probably twice, in both the USA and Australia.
Appearance
The mutation now known as the Dominant or Easley Clearbody was first described by its breeder, C F Easley. He said, "The body colour is changed from blue or green to white or yellow and the wing barring, flights and shaft feathers become jet black. Throat spots are black and the cheek patch is pale bluish or lavender." This describes perhaps the idealised variety, and only double factor Clearbodies approach this ideal. He goes on to say, "the clearness of the body and the darkness of the wing barrings depends on the strength of the factor in the individual bird", indicating the variability in residual suffusion and the intensity of the black markings.
Genetics
The Dominant Clearbody allele is dominant over its wild-type allele, so a bird possessing a single Dominant Clearbody allele (the heterozygote or single-factor Dominant Clearbody) is converted from the wild-type Light Green to a Dominant Clearbody (SF) Light Green as described in Appearance above. That is, the presence of a single Dominant Clearbody allele is sufficient to permit almost the full expression of the mutation.
The double-factor Dominant Clearbody, with two Dominant Clearbody alleles, is believed to have a clearer body and darker wing markings than the single-factor Dominant Clearbody.
The Dominant Clearbody gene is located on one of the autosomal chromosomes. There is no known linkage of this gene with any other mutation.