1. 1. Short, R. V. in Foetal Autonomy (eds Wolstenhome, G. E. W. & O'Connor, M.) 2-26 (Churchill, London, 1969). 2. Bazer, F. W., Vallet, J. L., Roberts, R. M., Sharp, D. C. & Thatcher, W. W. J. Reprod. Pert. 76, 841-850 (1986). 3. Godkin, J. D., Bazer, F. W., Moffatt, J., Sessions, F. & Roberts, R. M. /. Reprod. Fen. 65, 141-150(1982). 4. Godkin, J. D., Bazer, F. W., Thatcher, W. W. & Roberts, R. M. J. Reprod. Pert. 71, 57-64 (1984). 5. Godkin, J. D., Bazer, F. W. & Roberts, R. M. Endocrinology 114, 120-130 (1984). 6. Hansen, P. J., Anthony, R. V., Bazer, F. W., Baumbach, G. A. & Roberts, R. M. Endocrinology 117, 1424-1430 (1985). 7. Chirgwin, J. M., Przbyla, A. E., McDonald, R. J. & Rutter, W. J. Biochemistry 18, 5294-5299 (1979). 8. Aviv, H. & Leder, P. Proc. natn. Acad. Sci. U.S.A. 69, 1408-1412 (1972). 9. Roberts, B. E. & Patterson, B. M. Proc. natn. Acad. Sci. U.S.A. 70, 2330-2334 (1973). 10. Huynh, T. V., Young, R. A. & Davis, R. W. in DNA Cloning 1: A Practical Approach (ed. Glover, D. M.) 49-78 (IRL, Washington DC, 1985). 11. Young, R. A. & Davis, R. W. Proc. natn. Acad. Sci. U.S.A. 80, 1194-1198 (1983). 12. Chen, E. & Seeburg, P. H. DNA 4, 165-170 (1985). 13. Saul, A. & Yeganeh, F. Analyt. Biochem. 156, 354-356 (1986). 14. Polites, H. G. & Marotti, K. R. Biotechniques 4, 514-520 (1986). 15. Maniatis, T., Fritsch, E. F. & Sambrook, J in Molecular Cloning: A Laboratory Manual (Cold Spring Harbor Laboratory, New York, 1982). 16. Goedell, D. V. et al. Nature 290, 20-26 (1981). 17. Lawn, R. M. et al. Proc. natn. Acad. Sci. U.S.A. 78, 5435-5439 (1981). 18. Capon, D. J., Shepard, H. M. & Goeddel, D. V. Molec. cell. Biol. 5, 768-779 (1985). 19. Velan, B., Cohen, S., Grosfeld, H., Leitner, M. & Shafferman, A. /. biol. Chem. 260,5498-5504 (1985). 20. Shaw, G. D. et al. Nucleic Acids Res. 11, 555-573 (1983). 21. Dijkema, R., Pouwels, P., de-Reus, A. & Schellekens, H. Nucleic Acids Res. 12, 1227-1243 (1984). 22. Lefevre, F. & LaBonnardiere, C. J. Interferon Res. 6, 349-360 (1986). 23. Weinberger, C. et al. Science 228, 740-742 (1985). 24. Kronenberg, L. H. in Biotechnology: Applications and Research (eds Cheresmisinoff, P. & Ouellette, R.) 451-462 (Technomic, Lancaster, Pennsylvania, 1985). 25. Friedman, R. M., Merigan, T. & Sreevalsan, T. Interferons as Cell Growth Inhibitors and Antitumor Factors UCLA Symp on Molecular and Cellular Biology, Vol. 50 (Liss, New York, 1985). 26. Helmer, S. D. J. Reprod. Pert. 79, 83-91 (1987).