Book review: What does heredity mean these days?

I don’t do very many book reviews, but I jumped at the opportunity when the New York Times recently asked me to review Carl Zimmer’s new book “She has her mother’s laugh: The powers, perversions, and potential of heredity.”* As I was very familiar with Carl’s science writing, I had high expectations as I began reading, and he definitely exceeded them. This is a delightful monster of a book; 500+ pages that roam through subjects as diverse as Tasmanian devils’ facial tumors, CRISPR’d mosquitoes, and the legal system of property inheritance in ancient Rome. The theme connecting all these stories is our conception of heredity: what does it actually mean in an age of gene editing and surrogacy? (the title suggested for my review by my editor).



I found this subject personally fascinating, because I was able to connect with it strongly from the perspective of a new mother. Here is an excerpt from my review:

“She Has Her Mother’s Laugh” challenges our conventional wisdom about heredity, especially as we enter the new realms of surrogate pregnancy and gene editing. One of the most astonishing insights is that mothers don’t just pass traits to their children — they receive them as well. I read Zimmer’s book (occasionally out loud) while feeding my baby son. Like Zimmer, I had genetic counseling and my partner and I experienced the same anxieties as he did. But unlike Zimmer, I was able to assuage our fears using a drop of my own blood. That’s because my baby’s DNA, floating freely in my bloodstream, could be tested for hundreds of genetic disorders at an early point in my pregnancy. We took great comfort in the test, without realizing all of its implications. The baby wasn’t just sharing his genetic secrets during the pregnancy. Fetal cells can persist for years after birth; as I sit and write these sentences, I may very well be a chimera: a mixture of some of my son’s cells and my own. This microchimerism may even have eventual effects on my health, although it isn’t fully understood. And he may carry some of my immune cells, too.

I knew a bit about post-pregnancy microchimerism before reading this, but there’s a ton of details that I was unaware of, and now I want to go read the whole literature on the subject. Here’s a quote from the book that just astonished me:

“Fetal cells don’t simply migrate around their mothers’ bodies. They sense the tissue around them and develop into the same type of cells. In 2010, Gerald Udolph, a biologist in Singapore, and his colleagues documented this transformation with a line of engineered mice. they altered the Y chromosomes in the male mice so they glowed with the addition of a chemical. Udolph and his colleagues bred the mice, and then later they dissected the brains of the mothers. They found that the fetal cells from their sons reached into their brains, sprouted branches, and pumped out neurotransmitters. Their sons helped shape their thoughts.”


Even if that’s not been established as occurring in humans as well, that is really incredible.

Another major focus of the book that’s perhaps even more important from a social perspective was its treatment of the complex topics of heredity, biological race, and eugenics.  In this regard, I think that it’s a much better book than most that I’ve read on the subject, up there with Adam Rutherford’s “A brief history of everyone who ever lived”. It’s accessible without sacrificing accuracy, contextualizing the science with history and nuance.

This book is Zimmer at his best: obliterating misconceptions about science with gentle prose. He brings the reader on his journey of discovery as he visits laboratory after laboratory, peering at mutant mosquitoes and talking to scientists about traces of Neanderthal ancestry within his own genome. Any fan of his previous books or his journalism will appreciate this work. But so, too, will parents wishing to understand the magnitude of the legacy they’re bequeathing to their children, people who want to grasp their history through genetic ancestry testing and those seeking a fuller context for the discussions about race and genetics so prevalent today.

Here’s a link to my full review:

If you’re looking for some stimulating reading this summer, I highly recommend it!




*I’m posting this a bit late because the moment I finished writing the review I had to turn to developing my online summer course. Now I have a bit more breathing room, and time to blog more!

9 thoughts on “Book review: What does heredity mean these days?

  1. Mike Klymkowsky June 11, 2018 / 1:39 pm

    What seems missing is the fact that overt racism and excessive scientific hubris drove various eugenics movements. Science was used to obscure political motivations, which is what happens when people forget that scientific ideas are tentative rather than revealed truth.

    • Jennifer Raff June 14, 2018 / 10:39 am

      Hi Mike, Carl does go into the history of the eugenics movement in quite some detail in his book.

  2. Dr. Sherri T June 14, 2018 / 10:33 am

    Interesting the concern/interest about circulating fetal cells during pregnancy but give no thought to injecting your son with vaccines that include HUMAN fetal cells that have human DNA sequences.

    Dr. Theresa Deisher’s team discovered that the fetal DNA levels ranged anywhere from 142ng – 2000ng per dose, far beyond the so-called “safe” level.

    Click to access VaccinesPrint.pdf

    (And Amazon’s 4* and 5* comments about this book are unfavorable.)

  3. Jennifer Raff June 14, 2018 / 10:58 am

    Hi Sherri,

    You’re correct that Colin and I were not concerned at all about having our son fully vaccinated on-schedule, and he’s in perfect health. We’ll be taking him in for the next round, including MMR, in a few months. I’m looking forward to it since there’s been an outbreak of measles in Kansas City recently and I can’t wait until I no longer have to worry that he might get exposed.

    I’m a scientist who has worked with cell lines before (HeLa as it happens), and I understand the science behind them as well as the overwhelming evidence supporting the safety and efficacy of vaccines. These polemics you just posted don’t frighten me, nor should they frighten any parent.

    Where are you seeing unfavorable 4-5 star Amazon reviews of Zimmer’s book? There aren’t any 4 star reviews, and all of the 5 star reviews are favorable. And why is that relevant anyway? This is my review as an expert, and I loved the book.

  4. doritmi June 14, 2018 / 11:29 am

    I ordered the book. Thank you.

  5. JoanRN June 14, 2018 / 1:28 pm

    Great review for what sounds like a fascinating book. I can’t wait to read all of it. I’ve already started sharing the book and some information with mom/grandmom friends, nurse friends, nursing students. Thank you!

  6. Chris June 14, 2018 / 11:48 pm

    Haven had Dr. Deisher actually yell at me about the “dangers” of vaccines, I am more willing to take the Catholic Church’s official policy that it is better to prevent rubella than worry about something that happened fifty years ago. Especially after I read The Vaccine Race by Meredith Wadman.

    Now I must lament… Nooo….! I thought this summer I would be able to finally read The Gene: An Intimate History by Siddhartha Mukherjee. It is “only” about 600 pages long. Somewhere along with having a house remodeled, a son wedding and moving the youngest to another state for grad school.

    Thanks life!

    Now a an actual question: does Mr. Zimmer mention de novo mutations? It is kind of because we think that is why our old has a genetic heart disorder in which the genetic sequence has not been discovered (he had none of the then eighteen known) and he as autism. He also has a striking difference in his phenotype than his siblings.

    Yes, just like the little ditty on Sesame Street: in a picture of the three of them one just does not look like the others.

  7. Michael McClafferty June 29, 2018 / 5:56 am

    Thank you for this. I’ve been listening to this book since I read the above post (I do a lot of driving up and down the UK) and I find it absolutely fascinating. Though I haven’t yet finished it I love it’s examples of science sciencing correctly i.e. correcting itself sometimes messily and always with difficulty.

    Anyhoo, I don’t suppose you have other recommendations for books in this field or science in general?


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