How to draw confidence bounds to better demonstrate the confidence interval on ggplot2?

Question

This code draws the regression line, the confidence interval and the prediction interval. The confidence interval is colored in gray. I need to add a code to draw the confidence bounds to better demonstrate the confidence interval.

library(ggplot2)
x<-Allele<- c(4,4,5,5,5,7,9,11,11,11,13,14,15,15,16,17,17,19,19,19)
y<-SR<- c(5.5,5.6,5.7,6,6.1,8,8,12,12.1,13,14,14,16,16.5,17,17,
17.1,18,19,20)
D3S = data.frame(Allele, SR)
Mod <- lm(SR ~ Allele) 
pred.int <- predict(Mod, interval = "prediction")
mydata <- cbind(D3S, pred.int)
# Regression line + confidence interval
p <- ggplot(mydata, aes(Allele, SR)) +
geom_point(size=3) +
stat_smooth(method = lm, color="black")
# Add prediction intervals
myplot= p + geom_line(aes(y = lwr), color = "black", 
linetype = "dashed", size=0.8)+
geom_line(aes(y = upr), color = "black", 
linetype = "dashed", size=0.8)
myplot + theme_bw() + theme(panel.border = element_blank(), 
panel.grid.major = element_blank(),
panel.grid.minor = element_blank(), 
axis.line = element_line(colour = "black"))

Answer 1

You almost had it in your original code. Repeat the prediction with interval = "confidence" and add those lines to your plot.

# Right after you get the prediction intervals:
conf.int <- predict(Mod, interval = "confidence")

# Change the cbind line to this:
mydata <- data.frame(D3S, pred.int, conf.int) # checks names and adds .1 to dupes

# Right after you added prediction interval, do this:
myplot <- myplot + 
  geom_line(aes(y = lwr.1), color="red") + 
  geom_line(aes(y = upr.1), color="red")

Now produce your final plot as you did before.