A High-Resolution Genetic Map for the Laboratory Rat

Area of Science:

• Genetics
• Genomics
• Comparative Genomics

Background:

• The rat genetic map, essential for complex trait analysis, has remained outdated since 2004, lacking the resolution of human and mouse maps.
• Existing genetic maps limit the precision of quantitative trait loci (QTL) mapping in rats.

Purpose of the Study:

• To refine the rat genetic map to sub-centimorgan (cM) resolution, enhancing its utility for genetic research.
• To generate the first sex-specific rat genetic maps to investigate recombination rate variations.
• To provide an updated resource for the rat research community, including revised marker positions.

Main Methods:

• Utilized 95,769 genetic markers and 870 informative meioses from 528 heterogeneous stock (HS) rats.
• Developed sex-averaged and sex-specific genetic maps.
• Reanalyzed quantitative trait loci (QTL) using both historical and refined genetic maps.

Main Results:

• Achieved sub-centimorgan (cM) resolution (<0.02 cM) for the rat genetic map.
• Generated novel sex-specific maps revealing significant recombination rate variations between male and female rats.
• Demonstrated substantial changes in QTL localization, shape, and effect size upon reanalysis with the refined map.

Conclusions:

• The refined rat genetic map represents a significant advancement, offering unprecedented resolution for complex trait and recombination studies.
• The sex-specific maps provide crucial insights into sex-biased recombination patterns in rats.
• This updated resource, including revised marker positions, will greatly benefit the rat research community.