Added relative link to dna.py

diff --git a/testing/Writing.md b/testing/Writing.md
index b9f56146b9ace26b5c789bd7680bcd7e16dbbae4..17cc63b76b94c2cce2051c8079c47436e714c9c6 100755 (executable)
--- a/testing/Writing.md
+++ b/testing/Writing.md
@@ -1,6 +1,6 @@
 ## Let's start writing some tests
 
-In the file `dna.py` we have a Python dictionary that stores the molecular weights of the 4 standard DNA nucleotides, A, T, C and G, 
+In the file `[dna.py](python/dna/dna.py)` we have a Python dictionary that stores the molecular weights of the 4 standard DNA nucleotides, A, T, C and G, 
 
     NUCLEOTIDES = {'A':131.2, 'T':304.2, 'C':289.2, 'G':329.2}