- Polymorphisms in Chlamydia trachomatis tryptophan synthase genes differentiate between genital and ocular isolates. Caldwell, H.D., Wood, H., Crane, D., Bailey, R., Jones, R.B., Mabey, D., Maclean, I., Mohammed, Z., Peeling, R., Roshick, C., Schachter, J., Solomon, A.W., Stamm, W.E., Suchland, R.J., Taylor, L., West, S.K., Quinn, T.C., Belland, R.J., McClarty, G. J. Clin. Invest. (2003)