What types of non-allelic gene interactions do you know?

Genes are divided into allelic and non-allelic, depending on their location. Non-allelic genes are genes located in different parts of chromosomes.
Types of interaction of non-allelic genes:
The complementary (additional) action of genes is a type of interaction of non-allelic genes, the dominant alleles of which, when combined in the genotype, cause a new phenotypic manifestation of characters. An example is the inheritance of the shape of a pumpkin fruit. The presence of dominant genes A or B in the genotype determines the spherical shape of the fruit, and recessive – elongated. If there are simultaneously dominant genes A and B in the genotype, the fetal shape will be discoid. When pure lines are crossed with varieties having a spherical shape of the fruits, in the first hybrid generation F1, all fruits will have a disk-like shape, and in the generation F2, phenotype splitting will occur: out of every 16 plants, 9 will have disk-shaped fruits, 6 – spherical and 1 – elongated .
Epistasis is the interaction of non-allelic genes in which one of them is suppressed by the other. Genes that suppress the action of other genes are called inhibitor genes. Example. Dominant – hereditary diseases of people coincide with blood groups. The recessive is the “Bombay phenomenon.” A person has severe genetic diseases associated with the absence of any enzyme in the body. Sometimes such diseases are associated with epistasis, in which substances arising from the activity of an inhibitor gene interfere with the formation of vital enzymes encoded in another gene.
Polymeria – the interaction of non-allelic multiple genes that uniquely affect the development of one and the same trait; the degree of manifestation of the trait depends on the number of genes. Example. skin color in humans depends on four genes.
Pleiotropism. the dependence of several traits on one gene is called pleiotropy. This phenomenon was discovered even by Mendel, who noticed that in pea plants with red flowers, the stems are always darker than in individuals with white flowers.