Data hiding in deoxyribonucleic acid (DNA) emerges as an important topic in information security community. In this paper a new data hiding algorithm based on DNA sequence is proposed. The algorithm uses two DNA reference sequences; the first sequence is used for encrypting the secret message. The second sequence is used for hiding the cipher message. A DNA coding is used to encode the plaintext instead of the classical 8-bit ASCII coding. One advantage of the proposed algorithm is that; it has a low modification rate. In addition, the length of the DNA reference sequence remains unchanged. Experimental results show a better performance of the proposed algorithm with respect to several parameters such as capacity(C), payload and bit per nucleotide (bpn).