Understanding Genetics of Human Eye Color. Human Eye Color. In 1907, Charles and Gertrude Davenport outlined what is still commonly taught in schools today: Brown eye color is always dominant to blue; Two blue-eyed parents always produce a blue-eyed child, never one with brown eyes.
Human eye color and dark brown
comes from melanocytes: cells which make the brown pigment melanin.
Melanocytes are cells making melanin and melanosomes are bodies in the cytoplasm storing melanin. In the eye, melanin is not made continuously like in skin and hair.
The peripupillary ring is shown on the right and isn’t understood genetically yet.
Eumelanin is darker pigment in brown hair. Pheomelanin is lighter pigment in red hair
Ancient DNA with MC1R polymorphisms purified from the bones of two Neanderthals suggests that at least some of them had red hair and pale skin
Carles Lalueza-Fox, Holger Römpler, Michael Hofreiter et al., A melanocortin 1 receptor allele suggests varying pigmentation among Neanderthals. Science, October 25, 2007
A Three–Single-Nucleotide Polymorphism Haplotype in Intron 1 of OCA2 Explains Most Human Eye-Color Variation
David L. Duffy, Grant W. Montgomery, Wei Chen, Zhen Zhen Zhao, Lien Le, Michael R. James, Nicholas K. Hayward, Nicholas G. Martin, and Richard A. Sturm
a Transgenomic Wave System (model 2100D), for mutation detection, by use of the Navigator Software package. Samples with a mismatch in the analyzed PCR fragment were sequenced from new PCR products through use of ABI BigDye Terminator version 3.1 chemistry and were separated on a capillary-based genetic analyzer (Applied Biosystems). Sequence chromatograms were analyzed using the Sequencher program (Gene Codes).”Allele frequency associated with blue/gray eye color in this study.
bAllele frequency associated with nonblue eye color in this study.
cLikelihood-ratio test (MENDEL 6.01) for association between SNP and blue eye color.
Blue eye color.