European blue eye genetics: OCA2/HERC2 genes, sexual selection over low-light theory

European blue eye genetics: OCA2/HERC2 genes, sexual selection over low-light theory. European blue eyes are caused by OCA2 and HERC2 genes that only affect iris pigmentation The low-light vision hypothesis for blue eye evolution is rejected by most researchers Sexual selection is viewed as the main driving force for blue eye spread in Europe

That striking blue gaze? All in the genes. OCA2 and HERC2 affect iris pigmentation—but the genetic influence extends beyond just eye color to skin and hair as well. The 'low-light hunter' theory is rejected—studies show no improvement in night vision. Sexual selection is one leading hypothesis for the spread, though some researchers propose blue eyes may be a by-product of selection on skin pigmentation. The genetics are surprisingly specific.

Key Facts

• European blue eyes are caused by OCA2 and HERC2 genes that only affect iris pigmentation
• The low-light vision hypothesis for blue eye evolution is rejected by most researchers
• Sexual selection is viewed as the main driving force for blue eye spread in Europe
• Blue eye mutation likely originated in a small population in the Caucasus region
• The mutation may have started with a single individual and spread through sexual selection

Source: The "Dazzling Blue Eyes" of Indonesia and Africa Explained by Timeless with Fred Snyder