A predominantly French research team, led by Yann Guiguen (INRA), published in the April issue of Nature Communications the sequence and structure of the rainbow trout genome. It is a great achievement for a key species in world aquaculture, historically one of the first teleosts to be domesticated by humans.
The sequencing of the trout genome, accomplished by a team of 30 researchers, opens new possibilities for the aquaculture of this species, native of the North American Pacific coast. The aquaculture of the rainbow trout, initiated in 1874, reached in the year 2012 a global production level of 900,000 tonnes, with a net yield value of 4,5 billion Euros spread across 63 different countries.
This is an important step for the improvement of certain relevant issues in trout husbandry, such as resistance to disease, the selection of specific strains with higher growth potential, or better adapted to marine grow-out conditions. The prevalence of some viral diseases in the salmon industry emphasized the viability of naturally resistant, seawater-grown rainbow trout for the production of smoked fillets from larger size fish, in excess of 3 Kg in body weight.
This technical milestone is also important for our understanding of the evolution of this species. The success of this teleost seems related to the recent genome duplication event which occurred approximately 100 million years ago in the rainbow trout. In most vertebrates, including humans, a similar duplication event took place much earlier, and most duplicate genes have now been lost. However the trout still retains most of these genes, particularly those related to the regulation of gene expression. This could explain the impressive adaptability of the rainbow trout to different temperatures, climates and water qualities, making it one of the most ubiquitous fish species worldwide.