Non-allelic gene interactions refer to the interactions between genes that are located on different chromosomes and do not belong to the same gene locus. Some examples of non-allelic gene interactions are:

1. Epistasis
Epistasis is a type of gene interaction where the expression of one gene masks or modifies the expression of another gene. There are two types of epistasis - dominant epistasis and recessive epistasis. In dominant epistasis, the dominant allele of one gene masks the expression of another gene, whereas in recessive epistasis, the recessive allele of one gene masks the expression of another gene.

2. Complementation
Complementation is a type of gene interaction where two different genes complement each other to produce a specific phenotype. For example, if two homozygous recessive plants are crossed, and one plant has a mutation in gene A and the other plant has a mutation in gene B, the F1 offspring will have a wild-type phenotype because the two mutations complement each other.

3. Modifier genes
Modifier genes are genes that modify the expression of other genes. They do not mask the expression of other genes, but they can enhance or suppress the expression of other genes. For example, a modifier gene may increase the severity of a disease caused by a mutation in another gene, or it may reduce the severity of the disease.

4. Polygenic inheritance
Polygenic inheritance is a type of gene interaction where multiple genes contribute to a single phenotype. For example, height is a polygenic trait, and multiple genes contribute to the height of an individual.

In conclusion, non-allelic gene interactions are important in determining the phenotype of an organism. Epistasis, complementation, modifier genes, and polygenic inheritance are some examples of non-allelic gene interactions.