Reproduction in the phylum Porifera: a synoptic overview

Abstract

Sponges (phylum Porifera) are important organisms from an ecological, evolutionary and biotechnological point of view: i) they play relevant ecological roles in many marine communities and participate in crucial steps of the cycle of dissolved nutrients and organic matter; ii) their cellular and genetic traits still reflect and inform about the ancient transition between the unicellular condition and the multicellular organization of animals, and iii) they and/or their symbionts are a promising source of compounds of interest in biomedicine and some industrial processes. For these reasons, engineers, chemists, microbiologists, general ecologists, geneticists, and evolutionary biologists, who usually have little expertise with sponges, need to professionally approach the complex, unique reproductive biology of this group. This synoptic overview, which does not intend to be a comprehensive review, attempts to fulfill the needs of such a heterogeneous potential audience. It summarizes the general process of sexual and asexual reproduction in the phylum, combining both ecological and cytological data. Emphasis is made on the processes of spermatogenesis, oogenesis, and fertilization. In addition to outlining general processes, a brief mention of exceptions, recent relevant findings and the weak points in current knowledge is provided with the aim of encouraging future research.