Complex sentence: All species within the genus share the phycological properties that can lead to the production of large pearls of commercial value, and therefore attempts have been made to harvest pearls commercially from many different "Pinctada" species.
Split into simpler sentences: All species within the genus share the phycological properties that can lead to them making large pearls of commercial value. Attempts have been made to harvest pearls commercially from many "Pinctada" species.