It’s exciting to have complex scientific concepts explained in everyday language, in a way that makes you acknowledge the relevance of the topic and understand how it affects your life. There is a line of great books that do that. In general, they belong to a genre called ‘popular science’ books.
The Gene: An Intimate History by Siddartha Mukherjee – a cancer physician and researcher as well as a stem cell biologist and cancer geneticist – goes way beyond that narrow genre definition, though. With the objective of discussing “the birth, growth and the future of one of the most powerful and dangerous ideas” in science (the gene), the author explores historical facts and tells personal anecdotes about the main people involved in the narrated events, and bravely includes information about his own Indian family history – with its many cases of mental illnesses – to illustrate points and, ultimately, to justify his interest in the subject.
Containing a great number of literary and movie references, and using language that becomes poetic and evocative at times, the author does not hesitate to apply clarifying metaphors to help us understand processes and results. The Gene, therefore, must be categorized as a hybrid text, with strands of history, science, biographical data and literature tightly interwoven in a fascinating whole, in which issues of heredity, illness, normalcy, family and identity are discussed.
In this post, we list and summarize 10 key lessons we have learned. Of course, we will be simplifying and reducing much of the fascinating content you will find in the book.
1. Darwin and Mendel: The science of genetics started off in the middle of the 19th century, with the development of Darwin’s theory of the origin and evolution of species (based on the idea of mutations, natural selection and the survival of the fittest) and the first heredity experiments carried out by Gregor Mendel in his pea garden in the backyard of the Augustinian abbey where he lived. Mendel discovered that heredity was handed down through discreet units, which were much later – in 1909 – called genes.
2. Eugenics: In 1869, Francis Galton coins the term “eugenics,” in his book Heredity Genius. Eugenics misused new genetic discoveries, helping create distorted and evil racial hygiene government policies, which enabled the setup of special asylums and the submission of mentally ‘feeble’ women to sterilization by force in the 1920s in the US, and the promotion of Nazi ideas about the purification and preservation of the Aryans as a superior race during the 1930s and 40s, with the extermination of millions of human beings.
3. The gene: If the atom is the basic unit of the matter and provides an organizing principle for physics, genes represent a similar unit in biology and provide similar organizing functions. Genes are parts or stretches of chromosomes – “long, filamentous structures buried within cells.” Human cells contain forty-six chromosomes: 23 inherited from one of parent and 23 from the other. They provide recipes (instructions for processes: basically the making of different kinds of proteins) and regulate all the work done by our cells. They are located in the nucleus of the cell.
4. Chromosomes: Chromosomes are made up of a special molecule called DNA (deoxyribonucleic acid), composed of sugar, phosphate and four kinds of bases (guanine, thymine, adenine and cytosine). The DNA structure – discovered by Watson, Crick, Wilkins, and Franklin in 1953 – consists of a double helix format with two strands linked by the bases.
5. RNA (ribonucleic acid): RNA is another molecule, similar to the DNA in structure, but with a single strand. It copies stretches of code from the DNA and serves as a messenger, carrying instructions from the genes located in the nucleus to the cytoplasm – the liquid part of the cell outside the nucleus – where proteins will be assembled according to the RNA code. Proteins compose most of the structures of our tissues, signal the initiation of processes and accelerate chemical reactions in our bodies. They rule.
6. Diseases associated with genes: From 1978 to 1988 a series of disease-linked genes were mapped. There are basically two kinds of gene-related diseases: monogenetic (involving one gene, such as cystic fibrosisand Huntington’s disease) and polygenetic (involving the coordination of a number of genes – most diseases, including cancer and schizophrenia, belong in this category). Besides, the effect genes have on the development of diseases is influenced by the level of penetrance. This means that different gene-related diseases are more likely to express themselves than others. The environment also plays an important role, working as a trigger to some of the diseases.
7. The ‘gay gene’: As of 1993 scientists started wondering if homosexuality could be directly linked to a gene. While there is evidence that there is a strong correlation between sexual orientation and the presence of a gene or a group of genes located in a certain region of the X chromosome, no one knows for sure how the process of formation of sexual identity is carried out. There may be other regulators scattered across other parts of the genome (see definition below); there’s no doubt that powerful environmental inputs or triggers are also at play here.
8. Race: Genetic studies disprove the mythical concept of race. Studies show that there is more variation within a “race” (85% to 90% percent of the level of total diversity of the human genome) than between the so-called “races” (only 7%).
9. The genome: The genome is the collection of all genes (with annotations, footnotes, and references) found in a species. In human beings, it amounts to three billion base-pairs, divided up into 21,000 to 23,000 genes (differentiated parts or stretches of the whole genome). In the year 2000, a draft sequence of The Human Genome Project, an international initiative to map and sequence the entire human genome, was announced.
10. The future: In the past years or so, we have developed new technologies which allow us to manipulate, re-engineer and edit genomes. We are at the stage where scientists are able to alter the human genome permanently, but we still don’t know all the moral, ethical, and physical implications of that. One of the objectives of this book is to bring more people into this interesting discussion. For the first time in history we will be creating a new species of humanoids. It’s, therefore, essential that all kinds of voices in the global community express their concerns, present their cases, and share their perspectives before we go down this road, as the process may be irreversible.
Siddartha Mukherjee’s previous book – The Emperor of All Maladies: A Biography of Cancer – won the 2011 Pulitzer Prize for general nonfiction and the Guardian First Book Award.