Sex determination in pearl oyster: A mini review

Abstract

Pearl aquaculture is an intensive pearl production method which has gained much interest over the years with pearl oysters been the main organism involved in the production of sea pearls. This has attracted growth and reproduction research being conducted on the pearl oyster, with research targeted at producing viable stocks through breeding programs utilizing controlled reproduction. The commercially utilized method for the production of pearls is nucleus insertion operation, also known as the grafting operation. The success of these controlled reproduction and the nuclei insertion operation is highly dependent on the state of the gonads and mainly gametogenesis. Generally, the sex of an organism is determined by two factors; either genetic or environmental. sox 9, foxl 2, Gata-type zinc finger protein I (zglp1), Protein ovo (ovo) and the dmrt genes are involved in genetic sex determination of pearl oysters. Factors such as hormone administration, temperature, pollution, and culture conditions affect sex determination, and sometimes cause sex reversal of pearl oysters. In pearl oysters, gender has been reported to affect nacre formation and pearl quality. Pearls from males have uniform thickness and smoothness whiles those from females have several scratches. Nacre formation has also been reported to be associated with ovarian development. Sex determination in pearl oyster is therefore an essential mechanism to understand.