Oligogenic determination of @entity1286 analgesic magnitude: a genetic analysis of selectively bred XXXX lines.

@entity63747 @entity19 @entity14887 @entity1337 @entity1286
Two ongoing selective breeding projects have produced @entity19 that display divergent analgesic responses to @entity1286 . These two projects have selected for similar phenotypes: high and low @entity14887 @entity1337 (HAR/ @entity63747 lines; Portland, OR) and high and low swim stress-induced @entity1337 (HA/LA lines; Jastrzebiec, Poland). Evidence suggests genetic commonalities between @entity19 of the two projects. Using a Mendelian breeding protocol, we have recently found that one or two genetic loci predominantly determine the high @entity1286 @entity1337 exhibited by HA @entity19 . In the present study we demonstrate that the differential @entity1286 @entity1337 (5 mg/kg, i.p.) displayed by HAR and @entity63747 @entity19 is similarly oligogenic, predominantly determined by two unlinked loci. A complementation analysis, in which the analgesic responses to @entity1286 of the recessive homozygotes of each project (HAR and HA) were compared to those of their hybrid offspring (HAR x HA), revealed that different genetic loci have been fixed in each project. An intriguing bimodal distribution was observed in the HAR x HA population: Some HAR x HA hybrids displayed greater @entity1286 @entity1337 than either HAR or HA @entity19 , whereas others displayed minimal @entity1337 . @entity63747 x LA hybrids displayed less @entity1337 than either @entity63747 or LA @entity19 . The analgesic responses of HAR x LA and @entity63747 x HA @entity19 were comparable to those of their low-line parents. These findings indicate not only that different loci were responsible for producing high @entity1286 responders in each selection project but that these distinct loci can interact synergistically to produce "superhigh" and "superlow" responders.
