diff --git a/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/Kmer.java b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/Kmer.java
index 70b8bd6..e405424 100644
--- a/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/Kmer.java
+++ b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/Kmer.java
@@ -92,13 +92,13 @@
 			StringBuilder str = new StringBuilder();
 			for (int i = A; i <= T; i++) {
 				if ((left & (1 << i)) != 0) {
-					str.append((char)GENE_SYMBOL[i]);
+					str.append((char) GENE_SYMBOL[i]);
 				}
 			}
 			str.append('|');
 			for (int i = A; i <= T; i++) {
 				if ((right & (1 << i)) != 0) {
-					str.append((char)GENE_SYMBOL[i]);
+					str.append((char) GENE_SYMBOL[i]);
 				}
 			}
 			return str.toString();
@@ -118,17 +118,17 @@
 		}
 		return strKmer.toString();
 	}
-	
-	public static int getByteNumFromK(int k){
-		int x = k/4;
-		if (k%4 !=0){
-			x+=1;
+
+	public static int getByteNumFromK(int k) {
+		int x = k / 4;
+		if (k % 4 != 0) {
+			x += 1;
 		}
 		return x;
 	}
 
 	/**
-	 * Compress Kmer into bytes array AATAG will compress as [0 0 0 G][A T A A]
+	 * Compress Kmer into bytes array AATAG will compress as [0x000G, 0xATAA]
 	 * 
 	 * @param kmer
 	 * @param input
@@ -137,7 +137,7 @@
 	 *            position
 	 * @return initialed kmer array
 	 */
-	public static byte[] CompressKmer(int k, byte[] array, int start) {
+	public static byte[] compressKmer(int k, byte[] array, int start) {
 		final int byteNum = getByteNumFromK(k);
 		byte[] bytes = new byte[byteNum];
 
@@ -170,7 +170,7 @@
 	 *            Input new gene character
 	 * @return the shiftout gene, in gene code format
 	 */
-	public static byte MoveKmer(int k, byte[] kmer, byte c) {
+	public static byte moveKmer(int k, byte[] kmer, byte c) {
 		int byteNum = kmer.length;
 		byte output = (byte) (kmer[byteNum - 1] & 0x03);
 		for (int i = byteNum - 1; i > 0; i--) {
@@ -178,12 +178,101 @@
 			kmer[i] = (byte) (((kmer[i] >>> 2) & 0x3f) | (in << 6));
 		}
 
-		int pos = ((k - 1) % 4) * 2;
+		int pos = ((k - 1) % 4) << 1;
 		byte code = (byte) (GENE_CODE.getCodeFromSymbol(c) << pos);
 		kmer[0] = (byte) (((kmer[0] >>> 2) & 0x3f) | code);
 		return (byte) (1 << output);
 	}
 
+	public static byte reverseKmerByte(byte k) {
+		int x = (((k >> 2) & 0x33) | ((k << 2) & 0xcc));
+		return (byte) (((x >> 4) & 0x0f) | ((x << 4) & 0xf0));
+	}
 
+	public static byte[] reverseKmer(int k, byte[] kmer) {
+		byte[] reverseKmer = new byte[kmer.length];
 
+		int curPosAtKmer = ((k - 1) % 4) << 1;
+		int curByteAtKmer = 0;
+
+		int curPosAtReverse = 0;
+		int curByteAtReverse = reverseKmer.length - 1;
+		reverseKmer[curByteAtReverse] = 0;
+		for (int i = 0; i < k; i++) {
+			byte gene = (byte) ((kmer[curByteAtKmer] >> curPosAtKmer) & 0x03);
+			reverseKmer[curByteAtReverse] |= gene << curPosAtReverse;
+			curPosAtReverse += 2;
+			if (curPosAtReverse >= 8) {
+				curPosAtReverse = 0;
+				reverseKmer[--curByteAtReverse] = 0;
+			}
+			curPosAtKmer -= 2;
+			if (curPosAtKmer < 0) {
+				curPosAtKmer = 6;
+				curByteAtKmer++;
+			}
+		}
+
+		return reverseKmer;
+	}
+
+	/**
+	 * Compress Reversed Kmer into bytes array AATAG will compress as
+	 * [0x000A,0xATAG]
+	 * 
+	 * @param kmer
+	 * @param input
+	 *            array
+	 * @param start
+	 *            position
+	 * @return initialed kmer array
+	 */
+	public static byte[] compressKmerReverse(int k, byte[] array, int start) {
+		final int byteNum = getByteNumFromK(k);
+		byte[] bytes = new byte[byteNum];
+
+		byte l = 0;
+		int bytecount = 0;
+		int bcount = byteNum - 1;
+		for (int i = start + k - 1; i >= 0; i--) {
+			byte code = GENE_CODE.getCodeFromSymbol(array[i]);
+			l |= (byte) (code << bytecount);
+			bytecount += 2;
+			if (bytecount == 8) {
+				bytes[bcount--] = l;
+				l = 0;
+				bytecount = 0;
+			}
+		}
+		if (bcount >= 0) {
+			bytes[0] = l;
+		}
+		return bytes;
+	}
+
+	/**
+	 * Shift Kmer to accept new input
+	 * 
+	 * @param kmer
+	 * @param bytes
+	 *            Kmer Array
+	 * @param c
+	 *            Input new gene character
+	 * @return the shiftout gene, in gene code format
+	 */
+	public static byte moveKmerReverse(int k, byte[] kmer, byte c) {
+		int pos = ((k - 1) % 4) << 1;
+		byte output = (byte) ((kmer[0] >> pos) & 0x03);
+		for (int i = 0; i < kmer.length - 1; i++) {
+			byte in = (byte) ((kmer[i + 1] >> 6) & 0x03);
+			kmer[i] = (byte) ((kmer[i] << 2) | in);
+		}
+		// (k%4) * 2
+		if (k % 4 != 0) {
+			kmer[0] &= (1 << ((k % 4) << 1)) - 1;
+		}
+		kmer[kmer.length - 1] = (byte) ((kmer[kmer.length - 1] << 2) | GENE_CODE
+				.getCodeFromSymbol(c));
+		return (byte) (1 << output);
+	}
 }
diff --git a/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/KmerBytesWritable.java b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/KmerBytesWritable.java
index ea951ba..1d41167 100644
--- a/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/KmerBytesWritable.java
+++ b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/KmerBytesWritable.java
@@ -21,130 +21,131 @@
 import org.apache.hadoop.io.WritableComparable;
 import org.apache.hadoop.io.WritableComparator;
 
-public class KmerBytesWritable extends BinaryComparable implements WritableComparable<BinaryComparable> {
-    private static final int LENGTH_BYTES = 4;
-    private static final byte[] EMPTY_BYTES = {};
-    private byte size;
-    private byte[] bytes;
+public class KmerBytesWritable extends BinaryComparable implements
+		WritableComparable<BinaryComparable> {
+	private static final int LENGTH_BYTES = 4;
+	private static final byte[] EMPTY_BYTES = {};
+	private byte size;
+	private byte[] bytes;
 
-    public KmerBytesWritable() {
-        this(EMPTY_BYTES);
-    }
+	public KmerBytesWritable() {
+		this(EMPTY_BYTES);
+	}
 
-    public KmerBytesWritable(byte[] bytes) {
-        this.bytes = bytes;
-        this.size = (byte) bytes.length;
-    }
+	public KmerBytesWritable(byte[] bytes) {
+		this.bytes = bytes;
+		this.size = (byte) bytes.length;
+	}
 
-    @Override
-    public byte[] getBytes() {
-        return bytes;
-    }
+	@Override
+	public byte[] getBytes() {
+		return bytes;
+	}
 
-    @Deprecated
-    public byte[] get() {
-        return getBytes();
-    }
+	@Deprecated
+	public byte[] get() {
+		return getBytes();
+	}
 
-    @Override
-    public int getLength() {
-        return (int) size;
-    }
+	@Override
+	public int getLength() {
+		return (int) size;
+	}
 
-    @Deprecated
-    public int getSize() {
-        return getLength();
-    }
+	@Deprecated
+	public int getSize() {
+		return getLength();
+	}
 
-    public void setSize(byte size) {
-        if ((int) size > getCapacity()) {
-            setCapacity((byte) (size * 3 / 2));
-        }
-        this.size = size;
-    }
+	public void setSize(byte size) {
+		if ((int) size > getCapacity()) {
+			setCapacity((byte) (size * 3 / 2));
+		}
+		this.size = size;
+	}
 
-    public int getCapacity() {
-        return bytes.length;
-    }
+	public int getCapacity() {
+		return bytes.length;
+	}
 
-    public void setCapacity(byte new_cap) {
-        if (new_cap != getCapacity()) {
-            byte[] new_data = new byte[new_cap];
-            if (new_cap < size) {
-                size = new_cap;
-            }
-            if (size != 0) {
-                System.arraycopy(bytes, 0, new_data, 0, size);
-            }
-            bytes = new_data;
-        }
-    }
+	public void setCapacity(byte new_cap) {
+		if (new_cap != getCapacity()) {
+			byte[] new_data = new byte[new_cap];
+			if (new_cap < size) {
+				size = new_cap;
+			}
+			if (size != 0) {
+				System.arraycopy(bytes, 0, new_data, 0, size);
+			}
+			bytes = new_data;
+		}
+	}
 
-    public void set(KmerBytesWritable newData) {
-        set(newData.bytes, (byte) 0, newData.size);
-    }
+	public void set(KmerBytesWritable newData) {
+		set(newData.bytes, (byte) 0, newData.size);
+	}
 
-    public void set(byte[] newData, byte offset, byte length) {
-        setSize((byte) 0);
-        setSize(length);
-        System.arraycopy(newData, offset, bytes, 0, size);
-    }
+	public void set(byte[] newData, byte offset, byte length) {
+		setSize((byte) 0);
+		setSize(length);
+		System.arraycopy(newData, offset, bytes, 0, size);
+	}
 
-    public void readFields(DataInput in) throws IOException {
-        setSize((byte) 0); // clear the old data
-        setSize(in.readByte());
-        in.readFully(bytes, 0, size);
-    }
+	public void readFields(DataInput in) throws IOException {
+		setSize((byte) 0); // clear the old data
+		setSize(in.readByte());
+		in.readFully(bytes, 0, size);
+	}
 
-    @Override
-    public void write(DataOutput out) throws IOException {
-        out.writeByte(size);
-        out.write(bytes, 0, size);
-    }
+	@Override
+	public void write(DataOutput out) throws IOException {
+		out.writeByte(size);
+		out.write(bytes, 0, size);
+	}
 
-    @Override
-    public int hashCode() {
-        return super.hashCode();
-    }
+	@Override
+	public int hashCode() {
+		return super.hashCode();
+	}
 
-    @Override
-    public boolean equals(Object right_obj) {
-        if (right_obj instanceof KmerBytesWritable)
-            return super.equals(right_obj);
-        return false;
-    }
+	@Override
+	public boolean equals(Object right_obj) {
+		if (right_obj instanceof KmerBytesWritable)
+			return super.equals(right_obj);
+		return false;
+	}
 
-    @Override
-    public String toString() {
-        StringBuffer sb = new StringBuffer(3 * size);
-        for (int idx = 0; idx < (int) size; idx++) {
-            // if not the first, put a blank separator in
-            if (idx != 0) {
-                sb.append(' ');
-            }
-            String num = Integer.toHexString(0xff & bytes[idx]);
-            // if it is only one digit, add a leading 0.
-            if (num.length() < 2) {
-                sb.append('0');
-            }
-            sb.append(num);
-        }
-        return sb.toString();
-    }
+	@Override
+	public String toString() {
+		StringBuffer sb = new StringBuffer(3 * size);
+		for (int idx = 0; idx < (int) size; idx++) {
+			// if not the first, put a blank separator in
+			if (idx != 0) {
+				sb.append(' ');
+			}
+			String num = Integer.toHexString(0xff & bytes[idx]);
+			// if it is only one digit, add a leading 0.
+			if (num.length() < 2) {
+				sb.append('0');
+			}
+			sb.append(num);
+		}
+		return sb.toString();
+	}
 
-    public static class Comparator extends WritableComparator {
-        public Comparator() {
-            super(KmerBytesWritable.class);
-        }
+	public static class Comparator extends WritableComparator {
+		public Comparator() {
+			super(KmerBytesWritable.class);
+		}
 
-        public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
-            return compareBytes(b1, s1 + LENGTH_BYTES, l1 - LENGTH_BYTES, b2, s2 + LENGTH_BYTES, l2 - LENGTH_BYTES);
-        }
-    }
+		public int compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2) {
+			return compareBytes(b1, s1 + LENGTH_BYTES, l1 - LENGTH_BYTES, b2,
+					s2 + LENGTH_BYTES, l2 - LENGTH_BYTES);
+		}
+	}
 
-    static { // register this comparator
-        WritableComparator.define(KmerBytesWritable.class, new Comparator());
-    }
+	static { // register this comparator
+		WritableComparator.define(KmerBytesWritable.class, new Comparator());
+	}
 
 }
-
diff --git a/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/KmerCountValue.java b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/KmerCountValue.java
index 080110b..87eaa87 100644
--- a/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/KmerCountValue.java
+++ b/genomix/genomix-data/src/main/java/edu/uci/ics/genomix/type/KmerCountValue.java
@@ -20,15 +20,14 @@
 
 import org.apache.hadoop.io.Writable;
 
-
-public class KmerCountValue implements  Writable{
+public class KmerCountValue implements Writable {
 	private byte adjBitMap;
 	private byte count;
 
 	public KmerCountValue(byte bitmap, byte count) {
-		reset(bitmap, count);
+		set(bitmap, count);
 	}
-	
+
 	public KmerCountValue() {
 		adjBitMap = 0;
 		count = 0;
@@ -48,20 +47,24 @@
 
 	@Override
 	public String toString() {
-		return Kmer.GENE_CODE.getSymbolFromBitMap(adjBitMap) + '\t' + String.valueOf(count);
+		return Kmer.GENE_CODE.getSymbolFromBitMap(adjBitMap) + '\t'
+				+ String.valueOf(count);
 	}
 
-	public void reset(byte bitmap, byte count) {
+	public void set(byte bitmap, byte count) {
 		this.adjBitMap = bitmap;
 		this.count = count;
 	}
+
 	public byte getAdjBitMap() {
-        return adjBitMap;
-    }
+		return adjBitMap;
+	}
+
 	public void setAdjBitMap(byte adjBitMap) {
 		this.adjBitMap = adjBitMap;
 	}
+
 	public byte getCount() {
-	    return count;
+		return count;
 	}
 }
\ No newline at end of file
diff --git a/genomix/genomix-data/src/test/java/edu/uci/ics/genomix/example/kmer/KmerTest.java b/genomix/genomix-data/src/test/java/edu/uci/ics/genomix/example/kmer/KmerTest.java
index f391d9f..8dacea1 100644
--- a/genomix/genomix-data/src/test/java/edu/uci/ics/genomix/example/kmer/KmerTest.java
+++ b/genomix/genomix-data/src/test/java/edu/uci/ics/genomix/example/kmer/KmerTest.java
@@ -12,31 +12,70 @@
 	
 	@Test
 	public void TestCompressKmer() {
-		byte[] kmer = Kmer.CompressKmer(k, array, 0);
+		byte[] kmer = Kmer.compressKmer(k, array, 0);
 		String result = Kmer.recoverKmerFrom(k, kmer, 0, kmer.length);
 		Assert.assertEquals(result, "AATAGAA");
 		
-		kmer = Kmer.CompressKmer(k, array, 1);
+		kmer = Kmer.compressKmer(k, array, 1);
 		result = Kmer.recoverKmerFrom(k, kmer, 0, kmer.length);
 		Assert.assertEquals(result, "ATAGAAG");
 	}
 	
 	@Test
 	public void TestMoveKmer(){
-		byte[] kmer = Kmer.CompressKmer(k, array, 0);
+		byte[] kmer = Kmer.compressKmer(k, array, 0);
 		String result = Kmer.recoverKmerFrom(k, kmer, 0, kmer.length);
 		Assert.assertEquals(result, "AATAGAA");
 		
 		for (int i = k; i < array.length-1; i++) {
-			Kmer.MoveKmer(k, kmer, array[i]);
+			Kmer.moveKmer(k, kmer, array[i]);
 			Assert.assertTrue(false);
 		}
 
-		byte out = Kmer.MoveKmer(k, kmer, array[array.length - 1]);
+		byte out = Kmer.moveKmer(k, kmer, array[array.length - 1]);
 		Assert.assertEquals(out, Kmer.GENE_CODE.getAdjBit((byte) 'A'));
 		result = Kmer.recoverKmerFrom(k, kmer, 0, kmer.length);
 		Assert.assertEquals(result, "ATAGAAG");
 		
 	}
+	
+	@Test
+	public void TestReverseKmer(){
+		byte[] kmer = Kmer.compressKmer(k, array, 0);
+		String result = Kmer.recoverKmerFrom(k, kmer, 0, kmer.length);
+		Assert.assertEquals(result, "AATAGAA");
+		byte[] reversed = Kmer.reverseKmer(k, kmer);
+		result = Kmer.recoverKmerFrom(k, reversed, 0, kmer.length);
+		Assert.assertEquals(result, "AAGATAA");
+	}
+	
+	@Test
+	public void TestCompressKmerReverse() {
+		byte[] kmer = Kmer.compressKmerReverse(k, array, 0);
+		String result = Kmer.recoverKmerFrom(k, kmer, 0, kmer.length);
+		Assert.assertEquals(result, "AAGATAA");
+		
+		kmer = Kmer.compressKmerReverse(k, array, 1);
+		result = Kmer.recoverKmerFrom(k, kmer, 0, kmer.length);
+		Assert.assertEquals(result, "GAAGATA");
+	}
+	
+	@Test
+	public void TestMoveKmerReverse(){
+		byte[] kmer = Kmer.compressKmerReverse(k, array, 0);
+		String result = Kmer.recoverKmerFrom(k, kmer, 0, kmer.length);
+		Assert.assertEquals(result, "AAGATAA");
+		
+		for (int i = k; i < array.length-1; i++) {
+			Kmer.moveKmerReverse(k, kmer, array[i]);
+			Assert.assertTrue(false);
+		}
+
+		byte out = Kmer.moveKmerReverse(k, kmer, array[array.length - 1]);
+		Assert.assertEquals(out, Kmer.GENE_CODE.getAdjBit((byte) 'A'));
+		result = Kmer.recoverKmerFrom(k, kmer, 0, kmer.length);
+		Assert.assertEquals(result, "GAAGATA");
+	}
+
 
 }
diff --git a/genomix/genomix-hadoop/src/main/java/edu/uci/ics/graphbuilding/GenomixCombiner.java b/genomix/genomix-hadoop/src/main/java/edu/uci/ics/graphbuilding/GenomixCombiner.java
index 5e61c19..1a33c7a 100755
--- a/genomix/genomix-hadoop/src/main/java/edu/uci/ics/graphbuilding/GenomixCombiner.java
+++ b/genomix/genomix-hadoop/src/main/java/edu/uci/ics/graphbuilding/GenomixCombiner.java
@@ -49,7 +49,7 @@
             bytCount = (byte) 127;
         else
             bytCount = (byte) count;
-        vaWriter.reset(groupByAdjList, bytCount);
+        vaWriter.set(groupByAdjList, bytCount);
         output.collect(key, vaWriter);
     }
 }
diff --git a/genomix/genomix-hadoop/src/main/java/edu/uci/ics/graphbuilding/GenomixMapper.java b/genomix/genomix-hadoop/src/main/java/edu/uci/ics/graphbuilding/GenomixMapper.java
index 837866c..443cceb 100755
--- a/genomix/genomix-hadoop/src/main/java/edu/uci/ics/graphbuilding/GenomixMapper.java
+++ b/genomix/genomix-hadoop/src/main/java/edu/uci/ics/graphbuilding/GenomixMapper.java
@@ -78,27 +78,27 @@
             /** first kmer */
             byte count = 0;
             byte[] array = geneLine.getBytes();
-            byte[] kmer = Kmer.CompressKmer(KMER_SIZE, array, 0);
+            byte[] kmer = Kmer.compressKmer(KMER_SIZE, array, 0);
             byte pre = 0;
             byte next = GENE_CODE.getAdjBit(array[KMER_SIZE]);
             byte adj = GENE_CODE.mergePreNextAdj(pre, next);
-            outputAdjList.reset(adj, count);
+            outputAdjList.set(adj, count);
             outputKmer.set(kmer, 0, kmer.length);
             output.collect(outputKmer, outputAdjList);
             /** middle kmer */
             for (int i = KMER_SIZE; i < array.length - 1; i++) {
-                pre = Kmer.MoveKmer(KMER_SIZE, kmer, array[i]);
+                pre = Kmer.moveKmer(KMER_SIZE, kmer, array[i]);
                 next = GENE_CODE.getAdjBit(array[i + 1]);
                 adj = GENE_CODE.mergePreNextAdj(pre, next);
-                outputAdjList.reset(adj, count);
+                outputAdjList.set(adj, count);
                 outputKmer.set(kmer, 0, kmer.length);
                 output.collect(outputKmer, outputAdjList);
             }
             /** last kmer */
-            pre = Kmer.MoveKmer(KMER_SIZE, kmer, array[array.length - 1]);
+            pre = Kmer.moveKmer(KMER_SIZE, kmer, array[array.length - 1]);
             next = 0;
             adj = GENE_CODE.mergePreNextAdj(pre, next);
-            outputAdjList.reset(adj, count);
+            outputAdjList.set(adj, count);
             outputKmer.set(kmer, 0, kmer.length);
             output.collect(outputKmer, outputAdjList);
         }
diff --git a/genomix/genomix-hadoop/src/main/java/edu/uci/ics/graphbuilding/GenomixReducer.java b/genomix/genomix-hadoop/src/main/java/edu/uci/ics/graphbuilding/GenomixReducer.java
index 70981da..03bad56 100755
--- a/genomix/genomix-hadoop/src/main/java/edu/uci/ics/graphbuilding/GenomixReducer.java
+++ b/genomix/genomix-hadoop/src/main/java/edu/uci/ics/graphbuilding/GenomixReducer.java
@@ -50,7 +50,7 @@
             bytCount = (byte) 127;
         else
             bytCount = (byte) count;
-        valWriter.reset(groupByAdjList, bytCount);
+        valWriter.set(groupByAdjList, bytCount);
         output.collect(key, valWriter);
         reporter.incrCounter(MyCounters.NUM_RECORDS, 1);
     }
diff --git a/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/dataflow/KMerSequenceWriterFactory.java b/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/dataflow/KMerSequenceWriterFactory.java
index 51e5221..8c3f277 100644
--- a/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/dataflow/KMerSequenceWriterFactory.java
+++ b/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/dataflow/KMerSequenceWriterFactory.java
@@ -52,7 +52,7 @@
 
 				byte bitmap = tuple.getFieldData(1)[tuple.getFieldStart(1)];
 				byte count = tuple.getFieldData(2)[tuple.getFieldStart(2)];
-				reEnterCount.reset(bitmap, count);
+				reEnterCount.set(bitmap, count);
 				reEnterKey.set(kmer, keyStart, keyLength);
 				writer.append(reEnterKey, reEnterCount);
 				// @mark: this method can not used for read in hadoop 0.20.2.
diff --git a/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/dataflow/ReadsKeyValueParserFactory.java b/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/dataflow/ReadsKeyValueParserFactory.java
index 5764d3f..e5b7fa9 100644
--- a/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/dataflow/ReadsKeyValueParserFactory.java
+++ b/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/dataflow/ReadsKeyValueParserFactory.java
@@ -25,10 +25,12 @@
 
 	private int k;
 	private int byteNum;
+	private boolean bReversed;
 
-	public ReadsKeyValueParserFactory(int k) {
+	public ReadsKeyValueParserFactory(int k, boolean bGenerateReversed) {
 		this.k = k;
 		byteNum = (byte) Math.ceil((double) k / 4.0);
+		bReversed = bGenerateReversed;
 	}
 
 	@Override
@@ -56,22 +58,41 @@
 
 			private void SplitReads(byte[] array, IFrameWriter writer) {
 				/** first kmer */
-				byte[] kmer = Kmer.CompressKmer(k, array, 0);
+				byte[] kmer = Kmer.compressKmer(k, array, 0);
 				byte pre = 0;
 				byte next = GENE_CODE.getAdjBit(array[k]);
 				InsertToFrame(kmer, pre, next, writer);
 
 				/** middle kmer */
 				for (int i = k; i < array.length - 1; i++) {
-					pre = Kmer.MoveKmer(k, kmer, array[i]);
+					pre = Kmer.moveKmer(k, kmer, array[i]);
 					next = GENE_CODE.getAdjBit(array[i + 1]);
 					InsertToFrame(kmer, pre, next, writer);
 
 				}
 				/** last kmer */
-				pre = Kmer.MoveKmer(k, kmer, array[array.length - 1]);
+				pre = Kmer.moveKmer(k, kmer, array[array.length - 1]);
 				next = 0;
 				InsertToFrame(kmer, pre, next, writer);
+
+				if (bReversed) {
+					/** first kmer */
+					kmer = Kmer.compressKmerReverse(k, array, 0);
+					next = 0;
+					pre = GENE_CODE.getAdjBit(array[k]);
+					InsertToFrame(kmer, pre, next, writer);
+					/** middle kmer */
+					for (int i = k; i < array.length - 1; i++) {
+						next = Kmer.moveKmerReverse(k, kmer, array[i]);
+						pre = GENE_CODE.getAdjBit(array[i + 1]);
+						InsertToFrame(kmer, pre, next, writer);
+					}
+					/** last kmer */
+					next = Kmer.moveKmerReverse(k, kmer,
+							array[array.length - 1]);
+					pre = 0;
+					InsertToFrame(kmer, pre, next, writer);
+				}
 			}
 
 			private void InsertToFrame(byte[] kmer, byte pre, byte next,
@@ -105,7 +126,7 @@
 			@Override
 			public void open(IFrameWriter writer) throws HyracksDataException {
 				// TODO Auto-generated method stub
-				
+
 			}
 
 			@Override
diff --git a/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/job/GenomixJob.java b/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/job/GenomixJob.java
index 39f181a..0751707 100644
--- a/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/job/GenomixJob.java
+++ b/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/job/GenomixJob.java
@@ -21,6 +21,8 @@
 	public static final String GROUPBY_TYPE = "genomix.graph.groupby.type";
 	/** Graph outputformat */
 	public static final String OUTPUT_FORMAT = "genomix.graph.output";
+	/** Get reversed Kmer Sequence */
+	public static final String REVERSED_KMER = "genomix.kmer.reversed";
 
 	/** Configurations used by hybrid groupby function in graph build phrase */
 	public static final String GROUPBY_HYBRID_INPUTSIZE = "genomix.graph.groupby.hybrid.inputsize";
@@ -28,8 +30,8 @@
 	public static final String GROUPBY_HYBRID_RECORDSIZE_SINGLE = "genomix.graph.groupby.hybrid.recordsize.single";
 	public static final String GROUPBY_HYBRID_RECORDSIZE_CROSS = "genomix.graph.groupby.hybrid.recordsize.cross";
 	public static final String GROUPBY_HYBRID_HASHLEVEL = "genomix.graph.groupby.hybrid.hashlevel";
-	
-	public static final int DEFAULT_KMER= 55;
+
+	public static final int DEFAULT_KMER = 55;
 	public static final int DEFAULT_FRAME_SIZE = 32768;
 	public static final int DEFAULT_FRAME_LIMIT = 4096;
 	public static final int DEFAULT_TABLE_SIZE = 10485767;
@@ -38,10 +40,12 @@
 	public static final int DEFAULT_GROUPBY_HYBRID_RECORDSIZE_SINGLE = 9;
 	public static final int DEFAULT_GROUPBY_HYBRID_HASHLEVEL = 1;
 	public static final int DEFAULT_GROUPBY_HYBRID_RECORDSIZE_CROSS = 13;
-	
-	public static final String DEFAULT_GROUPBY_TYPE ="hybrid";
-	public static final String DEFAULT_OUTPUT_FORMAT ="binary";
-	
+
+	public static final boolean DEFAULT_REVERSED = false;
+
+	public static final String DEFAULT_GROUPBY_TYPE = "hybrid";
+	public static final String DEFAULT_OUTPUT_FORMAT = "binary";
+
 	public GenomixJob() throws IOException {
 		super(new Configuration());
 	}
diff --git a/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/job/JobGenBrujinGraph.java b/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/job/JobGenBrujinGraph.java
index b8e4219..683c0a1 100644
--- a/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/job/JobGenBrujinGraph.java
+++ b/genomix/genomix-hyracks/src/main/java/edu/uci/ics/genomix/job/JobGenBrujinGraph.java
@@ -66,6 +66,7 @@
 	private int tableSize;
 	private GroupbyType groupbyType;
 	private OutputFormat outputFormat;
+	private boolean bGenerateReversedKmer;
 
 	private AbstractOperatorDescriptor singleGrouper;
 	private IConnectorDescriptor connPartition;
@@ -207,7 +208,8 @@
 			}
 			LOG.info("HDFS read schedule " + log);
 			return new HDFSReadOperatorDescriptor(jobSpec, readOutputRec, job,
-					splits, readSchedule, new ReadsKeyValueParserFactory(kmers));
+					splits, readSchedule, new ReadsKeyValueParserFactory(kmers,
+							bGenerateReversedKmer));
 		} catch (Exception e) {
 			throw new HyracksDataException(e);
 		}
@@ -300,6 +302,9 @@
 				GenomixJob.GROUPBY_HYBRID_RECORDSIZE_CROSS,
 				GenomixJob.DEFAULT_GROUPBY_HYBRID_RECORDSIZE_CROSS);
 
+		bGenerateReversedKmer = conf.getBoolean(GenomixJob.REVERSED_KMER,
+				GenomixJob.DEFAULT_REVERSED);
+
 		String type = conf.get(GenomixJob.GROUPBY_TYPE,
 				GenomixJob.DEFAULT_GROUPBY_TYPE);
 		if (type.equalsIgnoreCase("external")) {
diff --git a/genomix/genomix-hyracks/src/test/java/edu/uci/ics/genomix/example/jobrun/JobRunTest.java b/genomix/genomix-hyracks/src/test/java/edu/uci/ics/genomix/example/jobrun/JobRunTest.java
index 3e80ab7..f9bf5b0 100644
--- a/genomix/genomix-hyracks/src/test/java/edu/uci/ics/genomix/example/jobrun/JobRunTest.java
+++ b/genomix/genomix-hyracks/src/test/java/edu/uci/ics/genomix/example/jobrun/JobRunTest.java
@@ -45,6 +45,7 @@
 			+ HDFS_OUTPUT_PATH + "/merged.txt";
 	private static final String CONVERT_RESULT = DUMPED_RESULT + ".txt";
 	private static final String EXPECTED_PATH = "src/test/resources/expected/result2";
+	private static final String EXPECTED_REVERSE_PATH = "src/test/resources/expected/result_reverse";
 
 	private static final String HYRACKS_APP_NAME = "genomix";
 	private static final String HADOOP_CONF_PATH = ACTUAL_RESULT_DIR
@@ -125,33 +126,59 @@
 		TestPreClusterGroupby();
 		cleanUpReEntry();
 		TestHybridGroupby();
+		cleanUpReEntry();
+		conf.setBoolean(GenomixJob.REVERSED_KMER, true);
+		TestExternalReversedGroupby();
+		cleanUpReEntry();
+		TestPreClusterReversedGroupby();
+		cleanUpReEntry();
+		TestHybridReversedGroupby();
 	}
 	
 	public void TestExternalGroupby() throws Exception {
 		conf.set(GenomixJob.GROUPBY_TYPE, "external");
-		conf.set(GenomixJob.OUTPUT_FORMAT, "binary");
 		System.err.println("Testing ExternalGroupBy");
 		driver.runJob(new GenomixJob(conf), Plan.BUILD_DEBRUJIN_GRAPH, true);
-		Assert.assertEquals(true, checkResults());
+		Assert.assertEquals(true, checkResults(EXPECTED_PATH));
 	}
 
 	public void TestPreClusterGroupby() throws Exception {
 		conf.set(GenomixJob.GROUPBY_TYPE, "precluster");
-		conf.set(GenomixJob.OUTPUT_FORMAT, "binary");
 		System.err.println("Testing PreClusterGroupBy");
 		driver.runJob(new GenomixJob(conf), Plan.BUILD_DEBRUJIN_GRAPH, true);
-		Assert.assertEquals(true, checkResults());
+		Assert.assertEquals(true, checkResults(EXPECTED_PATH));
 	}
 
 	public void TestHybridGroupby() throws Exception {
 		conf.set(GenomixJob.GROUPBY_TYPE, "hybrid");
-		conf.set(GenomixJob.OUTPUT_FORMAT, "binary");
 		System.err.println("Testing HybridGroupBy");
 		driver.runJob(new GenomixJob(conf), Plan.BUILD_DEBRUJIN_GRAPH, true);
-		Assert.assertEquals(true, checkResults());
+		Assert.assertEquals(true, checkResults(EXPECTED_PATH));
+	}
+	
+	public void TestExternalReversedGroupby() throws Exception{
+		conf.set(GenomixJob.GROUPBY_TYPE, "external");
+		conf.setBoolean(GenomixJob.REVERSED_KMER, true);
+		System.err.println("Testing ExternalGroupBy + Reversed");
+		driver.runJob(new GenomixJob(conf), Plan.BUILD_DEBRUJIN_GRAPH, true);
+		Assert.assertEquals(true, checkResults(EXPECTED_REVERSE_PATH));
+	}
+	public void TestPreClusterReversedGroupby() throws Exception{
+		conf.set(GenomixJob.GROUPBY_TYPE, "precluster");
+		conf.setBoolean(GenomixJob.REVERSED_KMER, true);
+		System.err.println("Testing PreclusterGroupBy + Reversed");
+		driver.runJob(new GenomixJob(conf), Plan.BUILD_DEBRUJIN_GRAPH, true);
+		Assert.assertEquals(true, checkResults(EXPECTED_REVERSE_PATH));
+	}
+	public void TestHybridReversedGroupby() throws Exception{
+		conf.set(GenomixJob.GROUPBY_TYPE, "hybrid");
+		conf.setBoolean(GenomixJob.REVERSED_KMER, true);
+		System.err.println("Testing HybridGroupBy + Reversed");
+		driver.runJob(new GenomixJob(conf), Plan.BUILD_DEBRUJIN_GRAPH, true);
+		Assert.assertEquals(true, checkResults(EXPECTED_REVERSE_PATH));
 	}
 
-	private boolean checkResults() throws Exception {
+	private boolean checkResults(String expectedPath) throws Exception {
 		File dumped = null;
 		String format = conf.get(GenomixJob.OUTPUT_FORMAT);
 		if ("text".equalsIgnoreCase(format)) {
@@ -206,7 +233,7 @@
 			dumped = new File(CONVERT_RESULT);
 		}
 
-		TestUtils.compareWithSortedResult(new File(EXPECTED_PATH), dumped);
+		TestUtils.compareWithSortedResult(new File(expectedPath), dumped);
 		return true;
 	}
 
diff --git a/genomix/genomix-hyracks/src/test/resources/expected/result_reverse b/genomix/genomix-hyracks/src/test/resources/expected/result_reverse
new file mode 100644
index 0000000..cf2712d
--- /dev/null
+++ b/genomix/genomix-hyracks/src/test/resources/expected/result_reverse
@@ -0,0 +1,8 @@
+AAGAT	G|A	5
+AATAG	|A	5
+AGAAG	T|	5
+AGATA	A|A	5
+ATAGA	A|A	5
+GAAGA	|T	5
+GATAA	A|	5
+TAGAA	A|G	5