- RIGG (Rosalind Institute Gallus gallus) oligo ID, gene symbol and description, and fold-change (Rf+/Rf- ratio) values are shown at two embryonic ages (e13 and e15). A preliminary analysis with a relaxed significance level (P ≤ 0.10) was completed using GeneSpring GX software (Agilent Technologies; Santa Clara, CA). Shaded expression values indicate higher expression of plasminogen activator inhibitor 1 (PAI-1) in liver of Rf- embryos