can anyone tell me why the scoring matrices used in ClustalW is PAM 350 and Blosum 30 not Pam250 or Blosum 62 which are more popular then PAM 350 and Blosum 30. And anyone know where i can read more on Fast & Slow Pairwise alignment on ClustalW. thanks suyee __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com