There are two copies of chromosome 15. Each copy has the bey2 gene. On one copy the bey2 gene is in the brown flavor, in the other the bey2 gene is in the blue flavor. Genes are particles that get inherited. Humans have several eye color genes.
Genes come in flavors called alleles.
The bey2 gene has two flavors - brown and blue. The gey gene also has two flavors - green and blue. Genes are on chromosomes. Chromosomes come in pairs. Thus each individual has two copies of each gene.