Eye colors of children came out as pure green, blue, or brown, not as a mixture of the colors of their parents' eyes. Children can have different eye colors than either of their parents. This is strange, if colors can't mix. It would make sense if colors mixed and blue and green eyed parents had greenish-blue eyed children. Brown tends to swamp out green, green tends to swamp out blue.
Genes are structures that are carried on larger structures called chromosomes.
The genes for each characteristic come in pairs, and the two genes together produce a given characteristic. One of the genes of the pair came from the father and the other came from the mother. An individual with brown and blue alleles of the bey2 gene on chromosome 15. There are two copies of chromosome 15. Each copy has the bey2 gene.