Selected gene sets (sGS) were downregulated in rag1−/− egg embryos but were similar in early hatched larvae and both showed high mortalities when infected by spring viremia carp virus (SVCV). (A) Expression folds in embryo eggs 1 day after fertilization (n = 60). Reverse transcriptase and quantitative polymerase chain reaction data were first normalized by the formula, expression of each gene/expression of ef1a. Differential folds were then calculated by the formula, normalized expression of each rag1−/− gene/normalized expression of each rag1+/+ gene. Tbk1 fold was lower than 2−6 (not shown). Tnfa and nklysin were not done. Red dashed line, onefold boundary. *Statistically different from onefold with p < 0.05 by the t-test. (B) Expression folds in hatched larvae 3 days after fertilization (n = 45) calculated as in (A). (C) Kaplan–Meier survival curves of naïve rag1−/− (n = 90) and rag+/+ (n = 90) recently hatched larvae after bath infection in 104 pfu of SVCV per ml (n = 2) at 22°C (optimal replication for SVCV). Differences between rag1−/− and rag+/+ survival curves of SVCV-infected larvae as determined by the Gehan–Breslow–Wilcoxon test were significant with p < 0.05 (*). Solid lines, rag1−/− larvae. Dashed lines, rag+/+ larvae.