          .attr("stroke", "black")
          .attr("stroke-width", "2")
 
- 
+
   # background rectangles for each chromosome, alternate color
   chrRect = topsvg.append("g").selectAll("empty")
      .data(data.chr)

                          .attr("y2", bottom[1] - tickHeight)
                          .attr("stroke", "black")
                          .attr("stroke-width", "1")
                          

  # chr labels
  topsvg.append("g").selectAll("empty")

         femaleloc2.push(xScale[2](i))
         femaleloc3.push(xScale[3](i))
     aves = [[average(femaleloc2), average(maleloc2)], [average(femaleloc3), average(maleloc3)]]

     # lower middle and lower right X axes
     for j in [2..3]
       XaxisGrp[j].selectAll("line").remove()
