lb130/+ dominantly suppresses the e15 backing defect and causes recessive sterility. Three phenotypes are present in this strain: backing steriles (lb130 homozygotes), backing fertiles which are bloated (heterozygotes), and non-backing coiled Unc animals which are fertile and bloated (sup-40(+)). Maintain strain by picking fertile animals which can back. egl-1(n487) is included in the strain to facilitate identification of lb130 homozygotes, which grow slowly; their sterility contrasts with the bloating of lb130/+ heterozygotes.