Gene visual

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
  </style>
</head>

var svg = d3.select("body").append("svg")
      .attr("width", 1000)
      .attr("height", 1000)

d3.json("genes.json", function (error, gene) {
    d3.select("svg").selectAll("rect")    
    .data(gene)
    .enter()
    .append("rect")
    .attr("x", function(d){return d.start})
    .attr("y", 50)
    .attr("width", function(d) {return d.stop-d.start})
    .attr("height", 50)
    .attr("fill", function(d)
        {if (d.orient == "forward")
          {return "blue"}
        else
      		{return "red"}
     
        })
    .style("stroke", "black")
    .style("stroke-width", 5)
  });

})
  </script>
</body>

https://d3js.org/d3.v4.min.js