The Molecular Basis of Life

MOST public interest in basic science research falls on individual experiments and the men who perform them. In the last few years, however, the entire field of molecular genetic has attracted an aura of scientific glamour. Newspaper stories about the isolation of the gene, genetic engineering, and "the secret of life itself" arouse the public's curiosity, and recent major advances in cancer and leukemia viral research excite even medical professionals. Research workers in molecular genetics are acutely aware of the implications of their work, of course, but usually prefer to separate personal reflections from the experimental observations that are reported in the scientific literature. Molecular Biology of the Gene (second edition), Professor Watson's new comprehensive introductory text to molecular genetics, supplements biochemical facts with relevant personal comment and opinion. In this manner, Watson presents the reader with both the substance and the glamour of modern molecular genetics.

Five years ago, Professor Watson wrote the first edition of Molecular Biology of the Gene, a comprehensive summary of work done in molecular genetics up to that time. But Watson included numerous predictions and assumptions that gave the book a personal, non-textbook character. In his 1965 preface, Watson wrote:

There may be readers troubled ... that I have stated the arguments too strongly, in view of the rapidly developing nature of our ideas about the genetic code, the replication of viruses, and the control of protein synthesis, I do not believe this to be the case.

In this first edition of his book, Watson presented experimental data with an explanation of its context in the on-going research at the time; his personal comments gave the book a relevancy that has outlived its press run. In fact, a year after the first edition was published, one biologist reportedly decided that the book was finally becoming up-to-date. At Harvard last year, this first edition was still recommended reading for half a dozen undergraduate biology, chemistry, and anthropology courses.

Now, in the new second edition of Molecular Biology of the Gene, Watson has improved the first edition by adding 150 pages of new information and by changing some parts of the first edition which recent work has shown to be inaccurate. The style, however, has not changed. Watson still includes personal comments where needed to propose a complete picture of his topic where the known facts present only a skeleton. For example, when discussing ribosomal structure, Watson says that "not even a semi-satisfactory hypothesis now exists for why ribosomes contain rRNA as well as protein." Nevertheless, in the next few sentences, Watson suggests a possible explanation for the function of rRNA at the ribosome; the reader who isn't satisfied with scientific ignorance is invited to consider Watson's opinions.

As long as the field of molecular genetics continues to grow, it becomes increasingly difficult to produce a book that is both introductory and comprehensive. Watson's new book very nearly does both. Professor Watson says that he would like to see Harvard undergraduate biology students take two years of introductory college biology- the first year would cover molecular biology, the material in Watson's book, and the second year would be similar to the present curriculum. For the interested beginning student, Molecular Biology of the Gene includes material, both general and specific, from the original key experiments up through the most recent evidence and theories.

For students who have completed introductory biology courses, or who have read the first edition of Molecular Biology of the Gene, Watson's second edition contains a few surprises. A lot has happened in molecular biology in the last five years, and most of the changes are reflected in comparison of the two editions. Substantial amounts of new information have accumulated in diverse areas: In the 1965 edition, Watson ended a chapter with the announcement that "much more must be learned about ribosomes." In the 1970 edition, there are twenty pages of new information. There is also new information on specific genetic mutagens, enzymes for genetic mutagens, enzymes for genetic recombination, specific factors to start and stop RNA transcription, new known gene codes, new material on operon-repressor systems, and much more.

Major additions in the areas of DNA replication and DNA and RNA viruses are sure to attract some attention. Students who took Nat Sci 5 or Bio 2 or any other introductory biology course before this year and think they learned about DNA replication in those classes will be surprised by Watson's new chapter on DNA duplication. DNA replication is often presented as the unwinding and subsequent rewinding of linear complementary ploy-nucleotide strands of DNA. However, this chapter now offers the Rolling Circle model of DNA replication, a complex model of revolving, duplicating circular DNA strands. Evidence is also given for the transition from linear DNA into these circular strands. Dr. David Dressler, a research fellow in the Watson-Gilbert labs here who was active in developing the Rolling Circle model, explains that the content, which is not necessarily complete and may not even actually exist as theorized, nevertheless is valuable because it enables researchers to combine the known evidence about DNA replication in one model.

The Rolling Circle idea is not the only mystery presented in this chapter. During the summer experiments were made that indicated that the polymerize enzyme researchers have been using to replicate DNA in the test tube may not be the same one living cells actually use. Watson's late publishing date enabled him to add some general comments on this evidence.

The reader searching for immediate medical and social relevance in molecular genetics will find the chapters on viruses and cancer especially informative. It's not necessary to be a hard-core biochemist to read Watson, and a look at these chapters will make technical papers and even newspaper stories about cancer experiments a lot more comprehensible. In the chapter entitled "A Geneticist's View of Cancer," Watson first discusses the specific changes cancerous cells undergo on infection, and then details the molecular mechanisms proposed for the transformation of cells by tumor viruses. If left at that, this chapter would be a valuable compilation of the present data on cancer induction, but Watson goes further. He discusses medical instances of cancer thought to be related to the tumor virus evidence and lists several interesting theories, one of which proposes a connection between cigarette smoking and oncogenic viruses.

The molecular biologist's contribution to medical research is already large, and is likely to grow with the expansion of cancer research. An examination of Molecular Biology of the Gene will give the reader not only a good understanding of molecular genetics, but a solid foundation for keeping up with future advances in medical and biological research.