However, these mapping studies showed that a single major QTL in each population colocalized with a candidate gene oca2. Oca2 loss-of-function mutations are known to cause albinism in other organisms, including humans, mice, and zebrafish, and deletions causing functional inactivation of Oca2 were identified in the albino fish from both the Molino and Pachón caves20. Here, OCA2 is linked to albinism.