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Mukherjee makes science history interesting, accessible and relevant. We learn about genetics and how a steady stream of brilliant and driven scientists uncovered the code that defines us all. Recent discoveries have given us the ability to change that code. Mukherjee presents the moral conundrums implicit in our new knowledge. The moral dilemma has a history too that is as important as that of the discoveries.

Mukherjee begins with Darwin and Mendel. Mendel’s 1856-63 studies of heritable traits in peas would go unnoticed, but Darwin’s 1859 On the Origin of Species drew immediate response. Many considered it blasphemy but in 1883, a year after Darwin’s death, his cousin Francis Galton grasped at a new idea coining the term “eugenics��. He called it “the science of improving stock to give the more suitable races or strains of blood a better chance of prevailing over the less suitable��. Evolutionary theory was barely out of the starting gate and its perversion was racing ahead of it.

Galton died in 1911, the year the American Charles Davenport published Heredity in Relation to Eugenics which became a widely used college text and primary reference for the movement. Many states enacted laws authorizing sterilization to eliminate “defective strains.�� Mukherjee dedicates his book to Carrie Buck who in 1924 in Virginia was classified as “feebleminded�� by doctors and ordered by a judge to the Virginia State Colony for Epileptics and the Feebleminded where her mother had been sent four years earlier. Carrie had been raped and was pregnant. To protect the perpetrator she had been characterized as promiscuous. Virginia wanted to sterilize her and launched a test case that went to the US Supreme Court in 1927. Against the backdrop of widespread fear of immigrants arriving from Southern and Eastern Europe the Court ordered her sterilized. Writing for the 8-1 majority the eminent Oliver Wendell Holmes stated, ”society can prevent those who are manifestly unfit from continuing their kind��. While America took the early lead, Germany would bring the eugenics movement to its gruesome conclusion.

In 1900 Mendel’s work was rediscovered and the search for heritable traits was on. From 1905 to 1925 Thomas Morgan and his associates tracked these traits in fruit flies in their Fly Room at Columbia University. They learned much about how genes worked but still did not know what genes were. In 1928 English bacteriologist Frederick Griffith showed that genes could be passed from one bacteria strain to another. In 1944 in New York molecular biologist Oswald Avery used Frederick Griffith’s work to pinpoint DNA as the genetic material. Next came a dramatic race among scientists won by James Watson, Francis Crick, Rosalind Franklin and Maurice Wilkins. In 1953 they identified DNA’s molecular structure, the famous double-helix. In 1959 Jacques Monad, Arthur Pardee and Francois Jacob published a paper showing how DNA operated through RNA to code proteins that in turn regulated DNA allowing each cell to carry out its own function.

In 1972 Paul Berg created DNA chimera combining genes from viruses and bacteria. This was not without risk. What if a new pathogen for which humans had no defense was unleashed? Soon after Herb Boyer and Stanley Cohen developed the ability to transfer genes from bacteria into mammalian cells and clone them. Frederick Sanger began to sequence them. In 1976 Herb Boyer was approached by venture capitalist Robert Swanson to exploit this new technology. He suggested they call the new company HerBob, but they settled on Genentech. By 1978 Genentech was making insulin, by 1982 human growth hormone and in 1983 an important blood clotting factor that meant hemophiliacs would not have to rely on AIDS infected blood transfusions. It continues to this day to produce a steady stream of important biological therapies.

In 1992 Craig Venter left NIH’s Human Genome Project to set up his own company, The Institute for Genomic Research (TIGR), dedicated to gene sequencing. In 1995 TIGR was the first to sequence all the genes of a living species, a bacterium. In 1998 Venter left TIGR to form a new gene sequencing company, Celera, derived from the word “accelerate��. Venter intended to beat NIH to be the first to sequence the human genome. That year NIH’s Worm Genome Project completely sequenced the first multicellular animal. Not to be outdone, Celera completely sequenced the fruit fly a year later. In 2000, President Clinton, afraid of the political fallout if the expensive NIH project was beaten by a private startup, engineered a truce. In 2000 Clinton called Venter and Francis Collins who headed NIH’s Human Genome Project to the White House to announce (a little prematurely) that both groups had sequenced the human genome. Both completed their projects and published their results in February 2001.

A new era in genetics was underway. Human lineage could be analyzed, ancestry determined and forensics vastly improved. Completely new avenues to diagnose disease, determine its cause and treat it were opened up. Gene therapy got off to an unfortunate start with the highly publicized death of Paul Gelsinger in 1999. But far better and more powerful techniques were coming. In 2012 Jennifer Doudna and Emmanuelle Charpentier published their findings about CRISPER. This bacterial defense system could be used to precisely splice genes. Human embryonic stem (ES) cells and human embryos could now be readily modified. After modification pluripotent ES cells could be converted back to embryos. The opportunities and risks are mindboggling.

I am struck by the timeliness of reading this in August 2017. In April the FDA approved 23andMe selling home testing for health related genes. Do you have a gene that increases your risk of Alzheimer’s or Parkinson’s? Now you can find out, but how will you handle the information? In June an FDA advisory committee recommended approval of a gene therapy, CAR-T, which holds much promise in the fight against cancer. If as expected the FDA approves in September, it will be the first gene therapy approved. We can expect subsequent approvals for gene tests and gene therapies to grow rapidly. In July a disease carrying gene was successfully replaced in a human embryo. Designer babies can’t be far in the future. Changes that have long been anticipated are upon us. Is our moral compass up to the responsibility science has placed upon us?

Reading Mukherjee’s book one gets a sense of the furious and ever quickening pace at which genetic technology has advanced. Profound capabilities will be readily available to change what we are. Genes define our mental attributes as well as physical features. What will we make of ourselves? It’s scary when we consider how well humans have managed our world and society. This is a 500 page book and much is left out in this review, particularly about how genes work which is explained well for a general audience. But the distinguishing feature of this book is to put forward the risks and moral hazards in balance with the great opportunity and benefit genetics holds. Everyone concerned about our future should pick this one up.