Eye color is a polygenic trait, influenced by multiple genes, but it is primarily determined by the presence and distribution of melanin in the iris. The basic understanding of eye color genetics involves two main genes: OCA2 and HERC2.
For blue eyes, the genotype generally involves one or two copies of a recessive allele associated with lower melanin production. The typical genotype for someone with blue eyes could be:
- homozygous recessive (bb) for the OCA2 gene, where 'b' signifies the allele responsible for blue eyes.
- or, they could be heterozygous (Bb) for the OCA2 gene, where the presence of a dominant brown allele (B) does not express as brown if there are other factors at play (e.g., if they also express a recessive allele in a different gene).
However, it is important to note that genetics is complex, and there can be variations due to other influencing genes. Therefore, while a person with blue eyes is likely to carry recessive alleles, the exact genotype can vary. Understanding eye color inheritance requires a broader view of genetic interactions rather than a simple dominant-recessive model.