I am trying to make a heat map using ggplot and geom_tiles using this code

HeLa_half_life_CpG <- read_excel("HeLa_mRNA_stability_chip1_2_combined.xlsx",
                                 sheet = "in_CpG")
melted_CpG <- melt(HeLa_half_life_CpG)
melted_CpG$Genes <- factor(melted_CpG$Genes, levels = unique(melted_CpG$Genes))
pdf("mRNA_stability_CpG.pdf", width = 3, height = 6)
ggplot(melted_CpG, aes(variable, Genes, fill= value)) + 
  geom_tile()+
  xlab("Hours")+
  ylab("")+
  labs(fill = "% mRNA remaining")+
  scale_fill_gradient(low="white",high="blue")+
  theme_minimal() +
  theme(
    text = element_text(size = 14),  # Adjust the size as needed
    axis.text.y = element_blank(), # Remove y-axis labels
    axis.text.x = element_text(size = 14),
    legend.position = "none")
dev.off()

The heatmap has white space between the tiles of each gene.

enter image description here

I want to remove this space, please help.

I tried

geom_tile(width = 1)

option but it didn’t work.