rna_fc <- rna %>% select(gene, time,
gene_biotype, expression_log) %>%
group_by(gene, time, gene_biotype) %>%
summarize(mean_exp = mean(expression_log)) %>%
pivot_wider(names_from = time,
values_from = mean_exp) %>%
mutate(time_8_vs_0 = `8` - `0`, time_4_vs_0 = `4` - `0`)