diff --git a/java/src/org/broadinstitute/sting/playground/gatk/walkers/varianteval/VariantEvalWalker.java b/java/src/org/broadinstitute/sting/playground/gatk/walkers/varianteval/VariantEvalWalker.java
new file mode 100755
index 000000000..65aa34e68
--- /dev/null
+++ b/java/src/org/broadinstitute/sting/playground/gatk/walkers/varianteval/VariantEvalWalker.java
@@ -0,0 +1,85 @@
+package org.broadinstitute.sting.playground.gatk.walkers.varianteval;
+
+import org.broadinstitute.sting.gatk.walkers.*;
+import org.broadinstitute.sting.gatk.refdata.RefMetaDataTracker;
+import org.broadinstitute.sting.gatk.refdata.rodDbSNP;
+import org.broadinstitute.sting.gatk.refdata.AllelicVariant;
+import org.broadinstitute.sting.gatk.LocusContext;
+import org.broadinstitute.sting.utils.BaseUtils;
+
+import java.util.EnumMap;
+
+/**
+ * Created by IntelliJ IDEA.
+ * User: mdepristo
+ * Date: Feb 22, 2009
+ * Time: 2:52:28 PM
+ * To change this template use File | Settings | File Templates.
+ */
+@By(DataSource.REFERENCE)
+@Requires(DataSource.REFERENCE)
+@Allows(DataSource.REFERENCE)
+public class VariantEvalWalker extends RefWalker<Integer, Integer> {
+    int N_TRANSITION_TRANVERSION_BINS = 100;
+    EnumMap<BaseUtils.BaseSubstitutionType, Integer> transition_transversion_counts[];
+
+    public void initialize() {
+        transition_transversion_counts = new EnumMap[N_TRANSITION_TRANVERSION_BINS];
+
+        for ( int i = 0; i < N_TRANSITION_TRANVERSION_BINS; i++ ) {
+            transition_transversion_counts[i] = new EnumMap<BaseUtils.BaseSubstitutionType, Integer>(BaseUtils.BaseSubstitutionType.class);
+            for ( BaseUtils.BaseSubstitutionType t : BaseUtils.BaseSubstitutionType.values() ) {
+                transition_transversion_counts[i].put(t, 0);
+            }
+        }
+    }
+
+    private int transition_transversion_bin(double MAF) {
+        return (int)Math.floor(MAF * N_TRANSITION_TRANVERSION_BINS);
+    }
+
+    private double transition_transversion_bin2MAF(int bin) {
+        return (bin + 0.5) / N_TRANSITION_TRANVERSION_BINS;
+    }
+
+    public Integer map(RefMetaDataTracker tracker, char ref, LocusContext context) {
+        AllelicVariant dbsnp = (AllelicVariant)tracker.lookup("dbSNP", null);
+
+        if ( dbsnp != null && dbsnp.isSNP() ) {
+            char refBase = dbsnp.getRefSnpFWD();
+            char altBase = dbsnp.getAltSnpFWD();
+            //System.out.printf("%c %c%n", refBase, altBase);
+            int i = transition_transversion_bin(dbsnp.getMAF());
+            //System.out.printf("MAF = %f => %d%n", dbsnp.getMAF(), i);
+            EnumMap<BaseUtils.BaseSubstitutionType, Integer> bin = transition_transversion_counts[i];
+
+            BaseUtils.BaseSubstitutionType subType = BaseUtils.SNPSubstitutionType(refBase, altBase);
+            bin.put(subType, bin.get(subType) + 1);
+            int sit = bin.get(BaseUtils.BaseSubstitutionType.TRANSITION);
+            int ver = bin.get(BaseUtils.BaseSubstitutionType.TRANSVERSION);
+            out.printf("%s %d %d %.2f %s%n", subType, sit, ver, (float)sit/ver, dbsnp.toString());
+        }
+
+        return 1;
+    }
+
+    // Given result of map function
+    public Integer reduceInit() { return 0; }
+    public Integer reduce(Integer value, Integer sum) {
+        return treeReduce(sum,value);
+    }
+    public Integer treeReduce(Integer lhs, Integer rhs) {
+        return lhs + rhs;
+    }
+
+    public void onTraversalDone(Integer result) {
+        for ( int i = 0; i < N_TRANSITION_TRANVERSION_BINS; i++ ) {
+            double averageMAF = transition_transversion_bin2MAF(i);
+            EnumMap<BaseUtils.BaseSubstitutionType, Integer> bin = transition_transversion_counts[i];
+            int sit = bin.get(BaseUtils.BaseSubstitutionType.TRANSITION);
+            int ver = bin.get(BaseUtils.BaseSubstitutionType.TRANSVERSION);
+            double ratio = (float)sit/ver;
+            out.printf("%.2f %d %d %f%n", averageMAF, sit, ver, ratio);
+        }
+    }
+}
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