Heritability of stress-ulcer susceptibility in rats.

This study was designed to provide estimates of the degree to which stress-ulcer susceptibility in the rat is genetically determined; whether that characteristic is a dominant, intermediate, or recessive trait; and how many genie units may be necessary to account for the observed trait variability. Parental populations of Sprague-Dawley rats and animals of the sixth generation of a stress-ulcer-susceptible (SUS) strain were used to produce F1( F2, and B, and B2 backcross generations. Analyses of the data on the severity of stress-ulcers that developed during 12 hr. of restraint indicated that: (1) over half the variability in stressulcer susceptibility is genetically determined, and (2) susceptibility is incompletely dominant over resistance to stress-ulceration.