Using genetics to unlock the growth potential in oysters

Researchers at Scotland's Roslin Institute have published multiple papers on oyster genetics that could help the industry produce larger and healthier shellfish.

The Fish Site
by The Fish Site
22 August 2022, at 10:10am
oysters
Different oyster specimens

Researchers developed extensive genetic resources that detail the DNA of oysters and used them to help address the challenges this species faces © Roslin Institute

Insights into the DNA of European flat oysters from a series of studies could inform selective breeding approaches for the scarce shellfish, to improve food security and sustainability.

Scientists from the Roslin Institute developed extensive genetic resources detailing the DNA of oysters and used them to help address the challenges this species faces in terms of conservation, restoration and aquaculture.

“Our results could contribute to sustainable food production, as oysters have among the lowest environmental impact of any animal protein production,” said Dr Tim Bean, Oyster research expert at the Roslin Institute.

The researchers found that two areas of the oyster genome are significantly associated with faster growth.

oyster basket with lighthouse in the background
Basket of farmed oysters

Scientists developed two high-quality reference genomes to aid in their research efforts

The incorporation of genomic information into breeding schemes could be a cost-effective way of enhancing growth traits such as weight and shell size in oysters, scientists concluded.

A separate study, led by scientists from the University of Santiago de Compostela and involving Roslin experts, discovered that variations in a region of oyster DNA may be associated with tolerance to a deadly parasite.

Reference genome

To help understand all the genetics information in their studies, the researchers decoded the complete DNA code of the European flat oyster.

Two high-quality reference genomes were separately built to the chromosome level by the Roslin team and scientists from Sorbonne University in France.

Both genomes have been published in Evolutionary Applications and are already being widely used by oyster researchers in Europe.

Growth traits

Scientists analysed the genome of the European flat oyster to look for variations and assess whether growth traits are under genetic control and could therefore be improved through selective breeding.

This research, published in Frontiers in Genetics, concluded that it is feasible to genetically improve growth traits in oysters.

sorting oysters
Sorting farmed oysters

The team explored areas of the oyster genome previously linked to resilience to the parasite and identified an area that was strongly associated with resilience to the parasite © Dorset Coast Forum

Parasite tolerance

In a separate study, scientists compared the genome of oysters that had not been exposed to the deadly parasite Bonamia ostreae with that of long-term affected populations.

The team explored areas of the oyster genome previously linked to resilience to the parasite and identified an area that was strongly associated with resilience to the parasite.

The study was published in Evolutionary Applications.

Oysters were once a plentiful source of food and a mainstay of the Scottish people but have long been in decline. The research at the Roslin Institute, in collaboration with UK and European academics, industry, environmental charities and government scientists, used genomics and genetic tools to help inform breeding strategies of the native European flat oyster.

“High quality reference genome assemblies are of immense value when applying genetic tools in aquaculture and conservation. Our genome assembly enhances the resources available for flat oyster research, supports ongoing conservation efforts and selective breeding programmes, and improves our understanding of bivalve genome evolution,” said Dr Manu Gundappa, Post-doctoral research fellow, Roslin Institute.

“Our study shows that breeding programmes for flat oyster aquaculture and restoration would benefit from the incorporation of genetic information to identify the best candidates for breeding, thereby fast-tracking genetic progress in key traits in a sustainable way,” said Dr Carolina Peñaloza, Post-doctoral research fellow, Roslin Institute.