PhD defence on population genomics in the native European flat oyster

The European flat oyster (Ostrea edulis) is the only native oyster species in Europe. It’s widespread across the European continent serving as a low-carbon food resource and providing numerous ecosystem benefits. However, overfishing, human-induced habitat destruction, and lethal parasitic diseases have left the species’ historical distribution depleted as well as locally extirpated. 

Actions to restore the European flat oyster, e.g. oyster supplementation, must consider the different genetic makeups of the species to account for genetic diversity and potential adaptation to specific localities. This could be important if some oyster populations are more resistant to parasites than others, for example. Also, genetic changes during hatchery production could affect biodiversity in the restored populations in nature.

During his PhD project at DTU Aqua, Homère J. Alves Monteiro participated in the development of a first chromosome-level genome for the European flat oyster, which served as a crucial resource for his work on natural and hatchery populations. The aim was to provide a comprehensive understanding of the genetic variation and diversity within and between populations, with a special focus on Scandinavian oyster populations.

Nearly 1000 oysters, mostly from wild populations, were sequenced, and the species' genetic structure across its range is now described. A significant discovery was the identification of a unique, previously unknown genetic group of oysters along the Norwegian west coast, signifying the rich genetic diversity of the species and highly localized signature of potential adaptation in the species genome. 

Another component of Homère J. Alves Monteiro’s PhD project was to investigate the reproductive success of oyster broodstock in hatcheries with a revamped genetic monitoring protocol. The experiments showed that a relatively small number of parent oysters typically produces the majority of offspring, which narrows the genetic diversity. This finding has critical implications for breeding and production protocols, emphasizing the importance of preserving genetic diversity in hatchery-produced oysters. 

Finally, Homère J. Alves Monteiro has examined how captivity influences the genomes of oyster aquaculture strains when compared to their wild counterparts. The results show profound genomic changes even after a few generations. 

About the PhD defence

Homère J. Alves Monteiro will defend his PhD thesis "Applied population genomics in the native European flat oyster (Ostrea edulis)” on Tuesday 4 July 2023, 13:00 on Zoom and at DTU Aqua, Vejlsøvej 39, 8600 Silkeborg. 

Supervisors

• Principal supervisor: Senior Researcher Jakob Hemmer Hansen, DTU Aqua
• Co-supervisor: Senior Researcher Dorte Bekkevold, DTU Aqua
• Co-supervisor: Senior Researcher Camille Saurel, DTU Aqua

Examiners

• Professor Einar Eg Nielsen, DTU Aqua (Chair)
• Associate Professor Matthew P. Hare, Cornell University, USA
• Head of Research Unit Pierre Boudry, IFREMER, France

Chairperson at defence

• Associate Professor Christian Skov, DTU Aqua

Learn more

A copy of the thesis is available by e-mail on request. Please contact Homère J. Alves Monteiro, homerejalvesmonteiro@gmail.com