Chapter 12 - Albinism

Albinism is widespread in the animal kingdom and is caused by the absence of melanin in the hair, eyes, or skin. Research on albinism has mainly focused on humans and mice and there is little directed research on albino echinoderms. In this chapter, the occurrence and mechanisms of albinism in the sea cucumber Apostichopus japonicus are discussed, and we conclude as follows: (1) The lack of melanin in the body wall is the direct cause of albinism in A. japonicus; (2) the lack of melanocytes and melanin synthesis in melanosomes are histological characteristics of albino A. japonicus; and (3) the significantly low microphthalmia-associated transcription factor (MITF) and astacin expression levels in A. japonicus are the molecular causes of albinism.