The different types of genes so far considered to be present and affecting the phenotypes of eukaryotes are: 1. Lethal Genes 2. Complementary Genes 3. Supplementary Genes 4. Inhibiting Genes 5. Duplicate Genes 6. Cumulative Genes 7. Collaborative Genes.
Type # 1. Lethal Genes:
The genes which are known to control the manifestation of some phenotype traits as well as affect the viability of the organism or only produce such serious effects that the organism possessing them are unable to survive.
Type # 2. Complementary Genes:
Two or more dominant genes present on separate gene loci which interact to produce a particular phenotypic trait, but neither of them produces the phenotypic trait in the absence of the other.
Type # 3. Supplementary Genes:
Two or more independent pairs of dominant genes which interact together in such a way that the dominant gene will produce its effect whether the other is present or not. The second dominant gene, when added, produces an altogether changed expression, but only in the presence of the first one.
Type # 4. Inhibiting Genes:
Two non-allelic genes (genes present on two separate loci) interacting together, in which one gene suppresses or masks the expression of the other gene.
Type # 5. Duplicate Genes:
Two or more genes situated on different chromosomes affecting the single trait.
Type # 6. Cumulative Genes:
Two or more independent pairs of genes which affect the same characteristics but in an additive fashion.
Type # 7. Collaborative Genes:
When two different genes are present on separate loci but influence the same trait, yet interact to produce some totally new single trait phenotype that neither of the genes by itself could produce.