     lodcurve_yScale = d3.scale.linear()
                         .domain([0, maxlod*1.05])
                         .range([bottom[1], top[1]])
+
+    # y-axis
+    yaxis = svg.append("g").attr("class", "probe_data").attr("id", "loweryaxis")
+    ticks = lodcurve_yScale.ticks(6)
+    yaxis.selectAll("empty")
+         .data(ticks)
+         .enter()
+         .append("line")
+         .attr("y1", (d) -> lodcurve_yScale(d))
+         .attr("y2", (d) -> lodcurve_yScale(d))
+         .attr("x1", left[1])
+         .attr("x2", right[1])
+         .attr("stroke", "white")
+         .attr("stroke-width", "1")
+    yaxis.selectAll("empty")
+         .data(ticks)
+         .enter()
+         .append("text")
+         .text((d) ->
+            return if maxlod > 10 then d3.format(".0f")(d) else d3.format(".1f")(d)) 
+         .attr("y", (d) -> lodcurve_yScale(d))
+         .attr("x", left[1] - pad.left*0.1)
+         .style("text-anchor", "end")
+    yaxis.append("line")
+         .attr("y1", lodcurve_yScale(5))
+         .attr("y2", lodcurve_yScale(5))
+         .attr("x1", left[1])
+         .attr("x2", right[1])
+         .attr("stroke", purple)
+         .attr("stroke-width", "1")
+         .attr("stroke-dasharray", "2,2")
+
     # lod curves by chr
     lodcurve = (c) ->
         d3.svg.line()

  # colors definitions
  lightGray = d3.rgb(230, 230, 230)
  darkGray = d3.rgb(200, 200, 200)
  pink = "#E9CFEC"
  purple = "#8C4374"
  # bgcolor = "black"
  labelcolor = "black"   # "white"

         .attr("fill", maincolor)
         .style("font-size", "18px")

    # black border
    svg.append("rect").attr("class", "probe_data")
       .attr("x", left[1])
       .attr("y", top[1])
       .attr("height", h[1])
       .attr("width", w[1])
       .attr("class", "outerBox")


  # circles at eQTL peaks
  peaks = svg.append("g").attr("id", "peaks")
             .selectAll("empty")
