data = read.table(text = "
start end av y1 y2 y3
719000 721000 720000 1 1 2
1199000 1201000 1200000 1 1 2
3039000 3041000 3040000 1 1 2
3679000 3681000 3680000 1 1 2
4119000 4121000 4120000 1 1 2
4999000 5001000 5000000 1 1 2", sep = " ", stringsAsFactors = F, header = T)

ids <- factor(paste(1:nrow(data), 1:nrow(data), sep = "."))

positions <- data.frame(
  id = rep(ids, times = nrow(data)/2),
  x = c(data$start, data$end, data$av),
  y = c(data$y1, data$y2, data$y3)
)

values <- data.frame(
  id = ids,
  value = 1:length(ids)
)

datapoly <- merge(values, positions, by = c("id"))

ggplot(datapoly, aes(x = x, y = y)) + geom_polygon(aes(fill = value, group = id))