Encouraged by the results with radiation genetics, the editors of this volume have tried since 1963 to organize a team of scientists in Heidelberg who would examine the problem of chemical mutagenesis in mammals with a variety of methods. Meanwhile, other organizations have also become interested in this problem and various teams, particularly in the U.S.A., but also in West Germany, are working in this field. This development is very auspicious; the spectrum of our methods does permit limited conclusions as to the mutagenic effects of chemical substances in mammals, but we are still far away from a thorough determination of all the genetically relevant effects. New methods must be developed. This volume is the result of a request by the Chairman of the "Gesellschaft fUr Anthropologie und Humangenetik", Frau Professor Dr. I. SCHWIDETZKY (Mainz), that one of us (F.V.) organize a symposium concerning mutation research in the framework of its annual meeting on October 7, 1969. The most sensible approach seemed to be one of centering the discussion on the test methods employed in mutagenicity research with mammals. With the aid of the Deutsche Forschungsgemeinschaft and the pharma ceutical industry it was possible to invite scientists from the U.S.A. We wish to thank Firma Thomae, Biberach, Firma Bayer, Leverkusen, and Firma Boehringer, Mannheim, for their contributions. We wish to thank Dr. HAsso SCHROEDER especially for his efforts on our behalf.

Aspects of the Problem

1. Biochemical Mechanisms of Mutation
2. Spontaneous Mutation in Man
3. Mutagenic Substances in the Human Environment
Research Methods
4. The Dominant Lethals: Method and Cytogenetic Examination of Early Cleavage Stages
5. The Multiple Loci Method
6. Evaluation of Presumed Dominant Skeletal Mutations
7. Histological and Cytogenetic Investigation Methods on Mammalian Spermatogenesis
8. Cytology and Timing of Meiotic Stages in Female Germ Cells of Mammals and Man
9. The Effect of Chemical Mutagens on the Mitotic Chromosomes of the Mouse, in vivo
10. Investigation of Bone Marrow Smears
11. Chromosome Aberrations in Plants
12. Possibilities and Limitations of Chromosome Treatment in vitro for the Problem of Chemical Mutagenesis
13. Point Mutations in Mammalian Cell Cultures as Measures for Mutagenicity Testing
14. Cytogenetic Analysis of Ascites Tumour Cells of Mice in Mutation Research
15. The Host-Mediated Assay, a Practical Procedure for Evaluating Potential Mutagenic Agents
16. The Internal Level of Mutagens in Mammals
17. Biochemical Analysis on Genetically Different and Altered DNA: Methods and Limitations
18. The Induction of Extrakaryotic Mutations
Findings and Application
19. The Activity of Alkylating Agents. I. Sensitive Mutable Stages in Spermatogenesis and Oogenesis
20. The Activity of Alkylating Agents. II. Histological and Cytogenetic Findings in Spermatogenesis
21. Chromosomal Aberrations Induced by Antimetabolites
22. Mutagenicity Experiments with Mice and Human Cell Cultures: Treatment with an Acridine Derivative (Trypaflavin)
23. The Treatment of Human Chromosomes in vitro: Results
24. The Problem of Caffeine Mutagenicity
25. The Failure of Caffeine to Induce Mutagenic Effects orto Synergize the Effects of Known Mutagens in Mice
26. Virus-Induced Chromosomal Alterations in Mammals and Man.
27. Statistical Examinations in Human Populations
28. Monitoring of Human Populations
29. Concluding Remarks
30. Statistical Methods in Mutation Research.