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".
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.
[2] In 1958 Gay Terraneo of Wilmington and Mr John Papin of Long Beach, both in California, obtained respectively a pair and a hen, and showed that the mutation is a sex-linked recessive.
In cocks, because Sex-linked Clearbody is recessive to wild-type and dominant to Ino, the Sex-linked Clearbody allele must be present on both Z chromosomes (homozygous) or present on one with an Ino allele on the other to be expressed in the phenotype.
The table on the right shows the appearance of all possible genetic combinations involving the Sex-linked Clearbody and the Ino mutations.
For these cross-over values, see the Genetics section in the Ino budgerigar mutation article.