A second generation genetic map for rainbow trout (Oncorhynchus mykiss)

Area of Science:

• Genomics
• Aquaculture
• Evolutionary Biology

Background:

• Genetic maps are crucial for understanding inheritance and have been developed for many species.
• Rainbow trout genetic maps are increasingly important for aquaculture, fisheries, and as a model organism for various research fields.
• Previous genetic maps for rainbow trout have been progressively improved over the last decade.

Purpose of the Study:

• To construct a second-generation genetic map for rainbow trout.
• To utilize microsatellite markers for enhanced genetic mapping.
• To facilitate quantitative trait loci (QTL) identification for aquaculture production traits and comparative genomics.

Main Methods:

• Genotyping 10 parents and 150 offspring from a reference family mapping panel.
• Utilizing 1124 microsatellite loci to construct the genetic map.
• Analyzing microsatellite markers in relation to expressed sequence tags and bacterial artificial chromosomes for comparative mapping.

Main Results:

• A sex-averaged genetic map of 2927.10 cM with 2.6 cM resolution was established.
• 180 duplicated regions were identified in the rainbow trout genome, indicative of a whole genome duplication event.
• Comparative assignments were made for 199 loci with zebrafish, medaka, tetraodon, and fugu genomes.

Conclusions:

• The new map offers increased microsatellite marker density and reveals sex-specific recombination rate differences.
• It can be integrated with physical and cytogenetic maps to study genome duplication.
• This resource will accelerate the identification of genes influencing important traits through fine mapping and positional cloning.