She Has Her Mother's Laugh presents a profoundly original perspective on what we pass along from generation to generation. Charles Darwin played a crucial part in turning heredity into a scientific question, and yet he failed spectacularly to answer it. The birth of genetics in the early 1900s seemed to do precisely that. Gradually, people translated their old notions about heredity into a language of genes. As the technology for studying genes became cheaper, millions of people ordered genetic tests to link themselves to missing parents, to distant ancestors, to ethnic identities...
But, Zimmer writes, 'Each of us carries an amalgam of fragments of DNA, stitched together from some of our many ancestors. Each piece has its own ancestry, traveling a different path back through human history. A particular fragment may sometimes be cause for worry, but most of our DNA influences who we are-our appearance, our height, our penchants - in inconceivably subtle ways.' Heredity isn't just about genes that pass from parent to child. Heredity continues within our own bodies, as a single cell gives rise to trillions of cells that make up our bodies. We say we inherit genes from our ancestors - using a word that once referred to kingdoms and estates-but we inherit other things that matter as much or more to our lives, from microbes to technologies we use to make life more comfortable. We need a new definition of what heredity is and, through Carl Zimmer's lucid exposition and storytelling, this resounding tour de force delivers it.
Weaving historical and current scientific research, his own experience with his two daughters, and the kind of original reporting expected of one of the world's best science journalists, Zimmer ultimately unpacks urgent bioethical quandaries arising from new biomedical technologies, but also long-standing presumptions about who we really are and what we can pass on to future generations.
In a magnificent work exploring virtually all aspects of heredity, journalist Zimmer (Parasite Rex), masterfully blends exciting storytelling with first-rate science reporting. Although he lucidly explains the basics of Mendelian genetics which address inheritance and biological diversity he goes far beyond that topic to explore the complexities of genetic inheritance. For example he notes that there are at least 800 genes influencing height in humans, but collectively they explain only about one-quarter of the heritability of that trait. Zimmer is not shy about taking on controversial topics like the genetics of race, arguing that there aren't genetic fingerprints for race ("Ancient DNA doesn't simply debunk the notion of white purity. It debunks the very name white"), and making the case that it is currently all but impossible to draw significant conclusions about the roles genes play in overall intelligence. He also probes developing field of epigenetics (changes in gene expression rather than alteration of genetic code) as well as the role of genetics in developmental and cancer biologies. Zimmer's writing is rich, whether he's describing the history of the field or examining the latest research and ethical issues certain to arise. His book is as engrossing as it is enlightening.