diff --git a/src/components/expression/expression.js b/src/components/expression/expression.js
index 1b472030..0484d92a 100644
--- a/src/components/expression/expression.js
+++ b/src/components/expression/expression.js
@@ -12,40 +12,130 @@ import actions from "../../actions";
   }
 })
 class DiffExp extends React.Component {
+  handleGeneColorScaleClick(gene) {
+    return () => {
+      this.props.dispatch(actions.requestSingleGeneExpressionCountsForColoringPOST(gene))
+    }
+  }
   render() {
     if (!this.props.differential.diffExp) return null
 
-
     const topGenesForCellSet1 = this.props.differential.diffExp.data.celllist1;
     const topGenesForCellSet2 = this.props.differential.diffExp.data.celllist2;
     const rectSide = 10;
     const rightMargin = 0;
 
+    const extent = d3.extent(
+      _.union(
+        topGenesForCellSet1.mean_expression_cellset1,
+        topGenesForCellSet1.mean_expression_cellset2,
+        topGenesForCellSet2.mean_expression_cellset1,
+        topGenesForCellSet2.mean_expression_cellset2
+      )
+    )
+
+    console.log('diffexp', this.props)
+    console.log('extent', extent)
+
+    const greyColorScale = d3.scaleSequential()
+        .domain(extent)
+        .interpolator(d3.interpolateGreys);
+
     return (
       <div>
-      <p> Top genes expressed by cellset 1 </p>
-      <p> Gene {"............"} Exp in set 1 {"............"} Exp in set 2 </p>
+      <div style={{
+        display: "flex",
+        justifyContent: "space-between",
+        width: 400,
+        fontWeight: 700,
+      }}>
+        <p style={{width: 200}}>Gene</p>
+        <p>Set 1 exp</p>
+        <p>Set 2 exp</p>
+      </div>
       {
         topGenesForCellSet1.topgenes.map((gene, i) => {
           return (
-            <p key={gene}>
-            {gene} {"...................... "}
-            {Math.floor(topGenesForCellSet1.mean_expression_cellset1[i])} {" ................... "}
-            {Math.floor(topGenesForCellSet1.mean_expression_cellset2[i])}
-            </p>
+            <div key={gene} style={{
+              width: 400,
+              display: "flex",
+              justifyContent: "space-between",
+              alignItems: "baseline",
+            }}>
+              <div style={{width: 200}}>
+                <span
+                  onClick={this.handleGeneColorScaleClick(gene).bind(this)}
+                  style={{
+                    fontSize: 24,
+                    cursor: "pointer",
+                    position: "relative",
+                    top: 5,
+                    marginRight: 10
+                  }}>🎨</span>
+                <span>{gene}</span>
+              </div>
+              <p style={{
+                padding: 20,
+                color: extent[1] === topGenesForCellSet1.mean_expression_cellset1[i] ? "white" : "black",
+                width: 60,
+                margin: 0,
+                backgroundColor: greyColorScale(Math.floor(topGenesForCellSet1.mean_expression_cellset1[i])),
+              }}>
+                {Math.floor(topGenesForCellSet1.mean_expression_cellset1[i])}
+              </p>
+              <p style={{
+                padding: 20,
+                color: extent[1] === topGenesForCellSet1.mean_expression_cellset2[i] ? "white" : "black",
+                width: 60,
+                margin: 0,
+                backgroundColor: greyColorScale(Math.floor(topGenesForCellSet1.mean_expression_cellset2[i])),
+              }}>
+                {Math.floor(topGenesForCellSet1.mean_expression_cellset2[i])}
+              </p>
+            </div>
           )
         })
       }
-      <p> Top genes expressed by cellset 2 </p>
-      <p> Gene {"............"} Exp in set 1 {"............"} Exp in set 2 </p>
       {
         topGenesForCellSet2.topgenes.map((gene, i) => {
           return (
-            <p key={gene}>
-              {gene} {"...................... "}
-              {Math.floor(topGenesForCellSet2.mean_expression_cellset1[i])} {" ................... "}
-              {Math.floor(topGenesForCellSet2.mean_expression_cellset2[i])}
-            </p>
+            <div key={gene} style={{
+              width: 400,
+              display: "flex",
+              justifyContent: "space-between",
+              alignItems: "baseline",
+            }}>
+              <div style={{width: 200}}>
+                <span
+                  onClick={this.handleGeneColorScaleClick(gene).bind(this)}
+                  style={{
+                    fontSize: 24,
+                    cursor: "pointer",
+                    position: "relative",
+                    top: 5,
+                    marginRight: 10
+                  }}>🎨</span>
+                <span>{gene}</span>
+              </div>
+              <p style={{
+                padding: 20,
+                color: extent[1] === topGenesForCellSet2.mean_expression_cellset1[i] ? "white" : "black",
+                width: 60,
+                margin: 0,
+                backgroundColor: greyColorScale(Math.floor(topGenesForCellSet2.mean_expression_cellset1[i])),
+              }}>
+                {Math.floor(topGenesForCellSet2.mean_expression_cellset1[i])}
+              </p>
+              <p style={{
+                padding: 20,
+                color: extent[1] === topGenesForCellSet2.mean_expression_cellset2[i] ? "white" : "black",
+                width: 60,
+                margin: 0,
+                backgroundColor: greyColorScale(Math.floor(topGenesForCellSet2.mean_expression_cellset2[i])),
+              }}>
+                {Math.floor(topGenesForCellSet2.mean_expression_cellset2[i])}
+              </p>
+            </div>
           )
         })
       }
@@ -54,6 +144,9 @@ class DiffExp extends React.Component {
   }
 }
 
+// <p> Top genes expressed by cellset 2 </p>
+// <p> Gene {"............"} Exp in set 1 {"............"} Exp in set 2 </p>
+
 
 @connect((state) => {
   return {
@@ -120,46 +213,74 @@ class Expression extends React.Component {
     ) {
       return null
     }
-
-    console.log('expression render sees', this.props.differential)
     return (
-      <div style={{marginTop: 50}}>
-        <SectionHeader text="Differential Expression"/>
-        <div style={{marginBottom: 20}}>
-          <button onClick={this.set1.bind(this)}>
+      <div>
+        <div style={{
+          marginBottom: 20,
+          width: 500,
+        }}>
+          <button
+            style={{
+              width: 200,
+              fontSize: 14,
+              margin: 5,
+              fontWeight: 400,
+              color: "#5A5F63",
+              padding: "10px 20px",
+              backgroundColor: "#C5D1D8",
+              border: "none",
+              borderRadius: 3,
+              cursor: "pointer",
+
+            }}
+            onClick={this.set1.bind(this)}>
             {
               this.props.differential.celllist1 ?
               this.props.differential.celllist1.length + " cells selected" :
               "Store current cell selection as 'set 1'"
             }
           </button>
-          <button onClick={this.set2.bind(this)}>
+          <button
+            style={{
+              width: 200,
+              fontSize: 14,
+              margin: 5,
+              fontWeight: 400,
+              color: "#5A5F63",
+              padding: "10px 20px",
+              backgroundColor: "#C5D1D8",
+              border: "none",
+              borderRadius: 3,
+              cursor: "pointer",
+
+            }}
+            onClick={this.set2.bind(this)}>
             {
               this.props.differential.celllist2 ?
               this.props.differential.celllist2.length + " cells selected" :
               "Store current cell selection as 'set 2'"
             }
           </button>
-          <button onClick={this.computeDiffExp.bind(this)}>
+          </div>
+        <div>
+          <button
+            style={{
+              fontSize: 14,
+              margin: 5,
+              fontWeight: 400,
+              color: "#41633C",
+              padding: "10px 20px",
+              backgroundColor: "#B9D1B5",
+              border: "none",
+              borderRadius: 3,
+              cursor: "pointer",
+
+            }}
+            onClick={this.computeDiffExp.bind(this)}>
             Compute differential expression
           </button>
-          Gene count:
-          <input placeholder={"Default is 5"}/>
         </div>
         <DiffExp/>
-        <SectionHeader text="Color by expression"/>
-        {
-          _.map(this.props.expression.genes, (gene) => {
-            return (
-              <button
-                key={gene}
-                onClick={this.handleClick(gene).bind(this)}
-                style={{marginRight: 10}}>
-                {gene}
-              </button>
-            )
-          })
-        }
       </div>
     )
   }
@@ -168,6 +289,25 @@ class Expression extends React.Component {
 export default Expression;
 
 
+// <SectionHeader text="Differential Expression"/>
+// <SectionHeader text="Color by expression"/>
+// {
+//   _.map(this.props.expression.genes, (gene) => {
+//     return (
+//       <button
+//         key={gene}
+//         onClick={this.handleClick(gene).bind(this)}
+//         style={{marginRight: 10}}>
+//         {gene}
+//       </button>
+//     )
+//   })
+// }
+
+
+// Gene count:
+// <input placeholder={"Default is 5"}/>
+
 // <svg>
 //   <g transform="translate(200, 40)">
 //     {
diff --git a/src/middleware/updateCellColors.js b/src/middleware/updateCellColors.js
index d1f3735d..b10997f4 100644
--- a/src/middleware/updateCellColors.js
+++ b/src/middleware/updateCellColors.js
@@ -79,10 +79,9 @@ const updateCellSelectionMiddleware = (store) => {
       }
 
       if (action.type === "color by expression") {
-        /* we assume if they clicked the control we must have loaded something, that could change though. */
 
-        /* this bit could be sped up and could be on the server, but it's drawn once on click, not at 60fps */
-        const indexOfGene = s.expression.data.genes.indexOf(action.gene);
+
+        const indexOfGene = 0 /* we only get one, this comes from server as needed now */
 
         const expressionMap = {}
         /*
@@ -93,34 +92,33 @@ const updateCellSelectionMiddleware = (store) => {
             cell789: [0, 8]
           }
         */
-        _.each(s.expression.data.cells, (cell) => {
+        _.each(action.data.data.cells, (cell) => { /* this action is coming directly from the server */
           expressionMap[cell.cellname] = cell.e
         })
 
-        const minExpressionCell = _.minBy(s.expression.data.cells, (cell) => {
+        const minExpressionCell = _.minBy(action.data.data.cells, (cell) => {
           return cell.e[indexOfGene]
         })
 
-        const maxExpressionCell = _.maxBy(s.expression.data.cells, (cell) => {
+        const maxExpressionCell = _.maxBy(action.data.data.cells, (cell) => {
           return cell.e[indexOfGene]
         })
 
+
+        console.log('middle', action, expressionMap, minExpressionCell)
+
+
         colorScale = d3.scaleLinear()
           .domain([minExpressionCell.e[indexOfGene], maxExpressionCell.e[indexOfGene]])
           .range([1,0]) /* invert viridis... probably pass this scale through to others */
 
-
-
         _.each(currentSelectionWithUpdatedColors, (cell, i) => {
-
           currentSelectionWithUpdatedColors[i]["__color__"] = d3.interpolateViridis(
             colorScale(
               expressionMap[cell.CellName][indexOfGene]
             )
           )
         })
-
-
       }
 
       /*