Heterozygous - Refers to a bird with two different alleles for a particular locus. This could be one wildtype allele and one mutant allele, or two different mutant alleles. Hemizygous refers to sexlinked recessive mutations that are expressed by a single allele in the heterogametic sex. Normally recessive alleles require two genes to be expressed, but the heterogametic sex does not have a second wildtype allele to suppress the sexlinked recessive trait. Autosomal - This refers to the autosomes, which are all the chromosomes other than the sex chromosomes.
Autosomal loci reside on the autosomes.
These mutations as described as being sexlinked. Recessive inheritance - Implies that the mutant allele is not expressed when heterozygous with the wildtype allele. A recessive mutation can be either autosomal or sex-linked. Many aviculturists do not understand that sex-linked mutations can be dominant or recessive in nature. It is just that almost all sex-linked mutations have proven recessive in nature.