Homozygous embryos display a partially penetrant dominant female sterile phenotype, a high frequency of embryos from heterozygous females have a dominant maternal bicaudal-like phenotype (mirror image duplication of abdominal segments). Timing of nuclear divisions of blastoderm homozygous embryos shows that the 12th mitotic cycle has slowed from 13 to 18 minutes. Homozygous embryos also display a nuclear holes phenotype, nuclei drop out of the periphery into the interior during mitotic cycles 11 to 13. Heterozygotes exhibit few nuclei that drop from the periphery.
Res1 is a suppressor of lethal phenotype of kniunspecified
Res1 suppresses the kni3/kni8 segmentation and lethal phenotype. kni3 Res1 double homozygous mutants have a wild type abdominal segmentation phenotype, but defective head skeleton and are embryonic lethal. knrl mediates Res rescue of the kni- abdominal segmentation phenotype. Embryos double heterozygous for Res1 thr1 have large numbers of dropping nuclei (evidence of a strong synergistic interaction between Res1 and thr1).
Rescues lethality of kni weak alleles.
99% of progeny inherit Res1 regardless of whether it is maternal or paternal contribution, this might be an example of genetic selfishness. Res1 is dependent upon a second locus to observe the chromosome segregation defect which is present on TM3.