Overlapping differentially expressed genes (DEGs) between NS and CRS in the blood of F344 and WKY suggest a convergence of stress-related molecular mechanisms, independent of stress-reactivity. In determining whether this strain-specific response to CRS was mirrored by transcriptomic changes in the blood, RNA sequencing was carried out. In contrast, remote memory was attenuated only in F344s after CRS. Both recent and reinstated fear memory were greater in F344s than WKYs, regardless of the stress status. Male F344 and WKY rats were exposed to the contextual fear conditioning (CFC) paradigm and then chronic restraint stress (CRS) or no stress (NS) was administered for two weeks before a second CFC. We explored this question using the average stress-reactive Fisher 344 (F344) rat strain and the Wistar–Kyoto (WKY) strain with its heightened stress-reactivity. Since individual variations in stress reactivity exist, and stress alters fear memory, exposing individuals with differing stress-reactivity to repeated stress would affect their fear memory to various degrees. The role of stress in altering fear memory is not well understood. WKY lineage-specific effects are highlighted in pink, while F344 lineage-specific effects are highlighted in yellow. ''F-females'' denotes F2 females derived from the F344 grandmaternal lineage, ''W-females'' are F2 females derived from the WKY grandmaternal lineage, ''F-males'' are F2 males derived from F344 grandmaternal lineage, ''W-males'' are F2 males derived from WKY grandmaternal lineage.
One-Way ANOVA was used to detect phenotypic differences between F344 homozygotes (FF), heterozygotes (FW), and WKY homozygotes (WW), with the probability of finding a difference by chance reflected in the p-values. Genotypes are shown on the X-axis, log transformed phenotypes on the Y-axis, with means ± SEM displayed. Allele-effect plots of F2 generation offspring stratified by sex and lineage showing the phenotypic effect of genotypes at (the marker most tightly linked to) each locus found to be significant in the initial genome scans and represented in Table II.