If genetically modified Atlantic salmon were to escape from captivity they could succeed in breeding and passing their genes into the wild, Canadian researchers have found. Their research, published in Evolutionary Applications, explores the potential reproductive implications of GM salmon as they are considered for commercial farming.
"The use of growth-enhancing transgenic technologies has long been of interest to the aquaculture industry and now genetically modified Atlantic salmon is one of the first species to be considered for commercial farming. Yet, little is known about the potential impact on wild salmon populations if the GM species were to escape captivity," said lead author Darek Moreau from the Memorial University of Newfoundland, Canada.
One of the key concerns about a transgene escape is the "Trojan gene effect", caused when a GM fish outcompetes or reproduces equally against wild rivals, however if the resulting offspring are genetically inferior this could lead a species towards eventual extinction. Until now there is no empirical research to demonstrate the ability of transgenic Atlantic salmon to breed naturally and infiltrate the wild gene pool.
In the wild, reproducing males present two main forms of rivals which any escaping transgenic male would have to compete with; large males which have migrated and returned from the sea and smaller male parr which have matured in freshwater. The large males are aggressive and develop attributes to fight off their rivals, while the smaller male parr use cryptic colouring and 'sneak fertilisation' to compete.
To measure the ability of transgenic males to complete with wild males during the reproductive season the team monitored breeding behaviour in a naturalised laboratory setting and used genetic analysis to determine the success of competing individuals at producing offspring.
Large, migratory wild males outperformed their captivity-reared tran
|Contact: Ben Norman|