Abstract
The mechanisms of sex determination and germline development are central topics in developmental and evolutionary biology; however, these processes remain unknown in most animal biodiversity. In this project, we studied these mechanisms in bivalve mollusks for two main reasons. First, Bivalvia are a highly diverse class, whose species differ profoundly in their biology and ecology, making them a valuable resource for better understanding the evolution of sex determination and its control by genetic and environmental factors. Second, many bivalves share economic and nutritional importance worldwide, and a thorough understanding of their reproductive biology would contribute to improving the aquaculture industry. We are using Mytilus galloprovincialis, the Mediterranean mussel, as a model species. This species is particularly suited to this project for two main reasons: 1) the presence of deviations from the 50:50 ratio of males and females that is female-dependent (up to 100% of one sex). This implies the existence of sex-inducing molecular factors deposited during oogenesis in oocytes; 2) the presence of double uniparental mitochondrial inheritance (DUI): sperm mitochondria display a sex-specific distribution pattern from the first embryonic division, allowing early inference of embryonic sex in vivo, which is impossible in non-DUI species. The project involves characterizing the early developmental stages of M. galloprovincialis, studying the molecular factors deposited in the oocyte and required for sex determination, the molecular mechanisms involved in early germline specification, and the factors involved in differential mitochondrial segregation. To achieve this goal, we compared the transcriptional profiles of male- and female-biased oocytes and, subsequently with single-cell RNA Sequencing, of early embryos with predetermined male or female sex with the aim to recognize and have a fingerprint of the transcriptome of the blastomeres that will give rise to the germline. With these approaches, we were able to identify genes associated with the different mitochondrial dynamics present in eggs that give rise to male- or female-dominant offspring, thus helping to unravel the general principles of organelle selection in animals. With this project, we provided valuable direct advances in understanding the basic biology of the mollusc bivalves. Furthermore, considering the important role played by these species both in ecological communities and from a commercial point of view, our results will have positive impacts on environmental monitoring programs and on the practical aspects of bivalve farming, as well as providing the scientific community with the first single-cell RNA Seq characterization of early embryonic development in M. galloprovincialis.
Dettagli del progetto
Responsabile scientifico: Liliana Milani
Strutture Unibo coinvolte:
Dipartimento di Scienze Biologiche, Geologiche e Ambientali
Coordinatore:
ALMA MATER STUDIORUM - Università di Bologna(Italy)
Contributo totale di progetto: Euro (EUR) 187.500,00
Contributo totale Unibo: Euro (EUR) 139.587,00
Durata del progetto in mesi: 24
Data di inizio
28/09/2023
Data di fine:
28/02/2026
