anchor.diff:              .domain([0, d3.max(hist)])
               .range([height, 0]);
           var svg = d3.select(div).append("svg")
  -            .attr("width", width + margin.left + margin.right)
  -            .attr("height", height + margin.top + margin.bottom)
  -            .append("g")
  -            .attr("transform", "translate(" + margin.left + "," + margin.top + ")");
  +            .attr("width", width)
  +            .attr("height", height)
  +            .append("g");
           var bar = svg.selectAll(".bar")
               .data(hist)
               .enter().append("g")
  
positive.code:             if (!$(this).is(":empty")) return;
              var gene = $(this).attr("alt");
              var mrna = cnas.getValue(gene, 'mrna');
              d3MrnaHist($(this)[0],mrna);
              $(this).qtip({
                  content: {text: "mRNA level of the gene in this tumor<br/><b>z-score</b>: "
                              +mrna.zscore.toFixed(2)+"<br/><b>Percentile</b>: "+mrna.perc+"%"},
  
negative.code:         });
      }
      
      function d3MrnaBar(div,mrnaPerc) {
          var width = 40,
              height = 12;
  
          var barWidth = Math.abs(mrnaPerc-0.5)*width;
  
          var svg = d3.select(div).append('svg')
              .attr("width", width)
              .attr("height", height)
              .append("g");
  
          svg.append("line")
              .attr("x1",width/2)
              .attr("y1",0)
              .attr("x2",width/2)
              .attr("y2",height)
              .attr("style", "stroke:gray;stroke-width:2");
  
          svg.append("rect")
              .attr("x", mrnaPerc>0.5 ? (width/2) : (width/2-barWidth))
              .attr("width", barWidth)
              .attr("y", 3)
              .attr("height", 6)
              .attr("fill", mrnaPerc>0.75 ? "red" : (mrnaPerc<0.25?"blue":"gray"));
  
      }
      
      function d3MrnaHist(div,mrna) {
          var hist = mrna.hist;
          var category = mrna.category;
          var width = 40,
              height = 12;
          var x = d3.scale.linear()
              .domain([0, 6])
              .range([0, width]);
  