Allele - A genes that occupies a loci is referred to as an allele. Alleles from each parent can be found on the chromosomes inhereted by the offspring. Dose - Each parent contributes an allele to their offspring and each contribution of a particular allele is considered a dose. For example, the characteristics for pearlscale will only occur if both parents contribute a pearlscale allele. When two different alleles for a particular characteristic is contributed, this is referred to as a hybrid.
Hybrids can occur in fish color, scale, or fin varieties.
Usually stable over generations, genes may be altered which are transferred to future generations. This is a rare occurance. An example of a mutant is the albino angelfish. Homozygous - Two alleles for a particular characteristic that appear at the same locus results in a true breeding for that particular trait. Recessive - Characteristic when a gene is carried by a heterozygous individual but not expressed.