Random amplification of polymorphic DNA (RAPD) was conducted by using 10 random primers (P-1 to P-10) inGracilaria lemaneiformis. Phase and sex specific bands were amplified by primers P-2, P-6, P-7 and P-8: for P-2 a 1.4 kb band was found in female gametophytes and tetrasporophytes, for P-6, a 0.6 kb band appeared in male gametophytes and tetrasporophytes; for P-7, a 0.76 kb band appeared in male gametophytes and tetrasporophytes; for P-7, a 0.72 kb band appeared in female gametophytes and tetrasporophytes; for P-8, a 0.73 kb band only appeared in male gametophytes.