Hybrid Rat Diversity Program (HRDP): A rat resource for mapping complex traits

Rats are a major model for studying complex disease mechanisms, behavioral phenotypes, environmental factors, and for drug development and discovery. Inbred rat strains control for genetic background and allow for repeated, reproducible molecular, cellular, and whole animal phenotyping. Genetic susceptibility to disease, sensitivity to environmental elements, and pharmacogenomics are critical components of the concepts of precision medicine. The Hybrid Rat Diversity Program (HRDP) is a resource that combines the power of genetic stability within strains, power for genomic mapping strategies, and strength in an animal model that mirrors many human disease traits. The HRDP was designed to include 96 inbred rat strains with genomic and physiological diversity to maximize power to detect specific genetic loci associated with complex traits while maximizing the genetic diversity among strains. The 96 strain panel consists of 33 genetically diverse inbred strains and two panels of recombinant inbred panels: FEXL/LEXF (33 strains, Japan) and HXB/BXH (30 strains, Czech Republic). Embryo resuscitation and breeding is well underway at the Medical College of Wisconsin (MCW) with 55 strains available. Whole genome sequencing for 54 of the 96 strains is complete, having been generated on am Illumina NovaSeq S4 to achieve 30X coverage. An additional 14 related substrains have been sequenced. Liver and brain transcriptome analysis is underway through PhenoGen (http://phenogen.ucdenver.edu) at the University of Colorado. Genomic, phenotype, and strain information will be made available through the Hybrid Rat Diversity Panel portal at the Rat Genome Database (http://rgd.mcw.edu). The HRDP will provide a genetically stable population of rat strains with fully sequenced genomes, transcriptomes for brain and liver, and general phenotypic characterization to be used for systems genetic studies and fine mapping of complex traits.