A Note from the Authors
The science of genetics is less than 150 years old, but its accomplishments within that short time have been astonishing. Gregor Mendel fi rst described genes as abstract units of inheritance in 1865; his work was ignored and then “rediscovered” in 1900. Thomas Hunt Morgan and his students provided experimental verifi cation of the idea that genes reside within chromosomes during the years 1910–1920. By 1944, Oswald Avery and his coworkers had established that genes are made of DNA. James Watson and Francis Crick published their pathbreaking structure of DNA in 1953. Remarkably, less than 50 years later (in 2001), an international consortium of investigators deciphered the sequence of the 3 billion nucleotides in the human genome. Twentieth century genetics made it possible to identify individual genes and to understand a great deal about their functions.
Today, scientists are able to access the enormous amounts of genetic data generated by the sequencing of many organisms’ genomes. Analysis of these data will result in a deeper understanding of the complex molecular interactions within and among vast networks of genes, proteins, and other molecules that help bring organisms to life. Finding new methods and tools for analyzing these data will be a signifi cant part of genetics in the twenty-fi rst century.
Our fourth edition of Genetics: From Genes to Genomes emphasizes both the core concepts of genetics and the cutting-edge discoveries, modern tools, and analytic methods that will keep the science of genetics moving forward.
Our Focus—An Integrated Approach
Genetics: From Genes to Genomes represents a new approach to an undergraduate course in genetics. It refl ects the way we, the authors, currently view the molecular basis of life. We integrate:
• Formal genetics : the rules by which genes are transmitted.
• Molecular genetics : the structure of DNA and how it directs the structure of proteins.
• Digital analysis, genomics, and proteomics : recent technologies that allow a comprehensive analysis of the entire gene set and its expression in an organism.
• Human genetics : how genes contribute to health and diseases, including cancer.
• The unity of life-forms : the synthesis of information from many different organisms into coherent models.
• Molecular evolution : the molecular mechanisms by which biological systems and whole organisms have evolved and diverged.
• Systems biology : the multidisciplinary, integrated study of life processes that may lead to new ways to analyze, detect, and treat disease.
The strength of this integrated approach is that students who complete the book will have a strong command of genetics as it is practiced today by both academic and corporate researchers. These scientists are rapidly changing our understanding of living organisms, including ourselves. Ultimately, this vital research may create the ability to replace or correct detrimental genes—those “inborn errors of metabolism,” as researcher Archibald Garrod called them in 1923, as well as the later genetic alterations that lead to the many forms of cancer.