Fedorowicz G M, Fry J D, Anholt R R, Mackay T F
Department of Zoology, North Carolina State University, Raleigh 27695-7614, USA.
Genetics. 1998 Apr;148(4):1885-91. doi: 10.1093/genetics/148.4.1885.
Odor-guided behavior is a polygenic trait determined by the concerted expression of multiple loci. Previously, P-element mutagenesis was used to identify single P[lArB] insertions, in a common isogenic background, with homozygous effects on olfactory behavior. Here, we have crossed 12 lines with these smell impaired (smi) mutations in a half-diallel design (excluding homozygous parental genotypes and reciprocal crosses) to produce all possible 66 doubly heterozygous hybrids with P[lArB] insertions at two distinct locations. The olfactory behavior of the transheterozygous progeny was measured using an assay that quantified the avoidance response to the repellent odorant benzaldehyde. There was significant variation in general combining abilities of avoidance scores among the smi mutants, indicating variation in heterozygous effects. Further, there was significant variation among specific combining abilities of each cross, indicating dependencies of heterozygous effects on the smi locus genotypes, i.e., epistasis. Significant epistatic interactions were identified for nine transheterozygote genotypes, involving 10 of the 12 smi loci. Eight of these loci form an interacting ensemble of genes that modulate expression of the behavioral phenotype. These observations illustrate the power of quantitative genetic analyses to detect subtle phenotypic effects and point to an extensive network of epistatic interactions among genes in the olfactory subgenome.
气味引导行为是一种由多个基因座协同表达决定的多基因性状。此前，P 因子诱变被用于在共同的同基因背景中鉴定单个 P[lArB]插入，这些插入对嗅觉行为具有纯合效应。在这里，我们采用半双列杂交设计（排除纯合亲本基因型和正反交），将 12 个带有这些嗅觉受损（smi）突变的品系进行杂交，以产生所有可能的 66 个双杂合杂种，这些杂种在两个不同位置带有 P[lArB]插入。使用一种测定法来测量反式杂合后代的嗅觉行为，该测定法量化了对驱避性气味剂苯甲醛的回避反应。在 smi 突变体中，回避分数的一般配合力存在显著差异，表明杂合效应存在差异。此外，每个杂交组合的特殊配合力之间存在显著差异，表明杂合效应依赖于 smi 基因座基因型，即上位性。在 9 种反式杂合子基因型中鉴定出显著的上位性相互作用，涉及 12 个 smi 基因座中的 10 个。其中 8 个基因座形成了一个相互作用的基因集合，调节行为表型的表达。这些观察结果说明了数量遗传分析检测细微表型效应的能力，并指出嗅觉亚基因组中基因之间存在广泛的上位性相互作用网络。
