SHE HAS HER MOTHER’S LAUGH | by Carl Zimmer, Dutton Press, 672p. Zimmer, an NYT science columnist, pens an extraordinary tour de force of the history and misuse of genetic science to the present-day landscape of its discoveries. It tarries a tad when the writer indulges in his narrative to illustrate a few points, but it serves a purpose. Fresh insights include the notion a birth mother carries with her - for years - the child's DNA. Like a chimera, the child’s DNA is floating through her bloodstream, altering her genetic makeup. Currently, scientists are unsure of how much the mother’s health is impacted by the baby’s genetic material. The reader will be thoroughly disabused of the concept of a gene-for-it idea. Genes and their attendant expression are highly complex. Take intelligence: You might be of average intelligence, but your offspring is naturally brilliant. Or height, where not one gene makes the difference but over 800 (of 3B) of them. This insight alone, Zimmer hopes, will be a bulwark against the folly that early genetic understandings succumbed to. As leveling technologies such as CRISPR become available, the inability to “simply” edit will prevent undue harm and maintain our humility for impacting DNA. Many of our social concepts of related families have a new definition as their rigidity breaks down. For example, the mother whose blood and skin DNA do not match her children, but cervix tissue samples do. She is the mother but related by blood in a fashion slightly different than we often conceptualize. Zimmer delivers a highly informative, albeit wordy, panorama of genetic history and its promise.