evolgen

Developmental Genetics Comes to Life

During the early part of the twentieth century, biological research was somewhat disjointed. Naturalists studied organisms and populations in the wild; geneticists were working out the mechanisms of heredity; and other researchers were figuring out how animals develop from a fertilized egg to an adult. One important union occurred when the naturalists and geneticists came together to study the genetics of natural populations. This led to the field of population genetics, which is still providing us with insights into the mechanisms of evolution today. Another major advance occurred when researchers began using genetic tools to understand animal development.

Early research on animal development used frog and sea urchin embryos. Important findings were made using these models, but they were not amenable for large scale genetic studies. The frog Xenopus laevis has a large embryo, which makes it excellent for studying development, but it is also tetraploid and has a long generation time (1-2 years). The inability to perform genetic analyses on these models meant that researchers could not do important experiments using mutant individuals to understand how specific gene products influenced developmental pathways.

It was because of these limitations that scientists began looking for model organisms that could be used to understand the genetics of development. Drosophila melanogaster played an important role in the study of genetics and heredity. Because it was already a model for genetical research, biologists could create mutations that affected developmental processes without much difficulty. For their work on the genetics of early development in D. melanogaster, Ed Lewis, Christiane Nusslein-Volhard, and Eric Wieschaus earned the 1995 Nobel Prize in Physiology or Medicine. Other popular models include the round worm Caenorhabditis elegans and the zebrafish Danio rerio, but genetical and developmental research on these two species was started in concert without much of a history of either type of study.

The field of the developmental genetics has moved quite rapidly in the past few decades because of the power of the aforementioned model organisms. The research communities that study each of these organisms have techniques that allow them to selectively knockout certain genes and study expression in individual tissues, and they have complete genome sequences from which to search for genes of interest. They also study topics that are at the forefront of political debates about science: cloning, stem cells, genetic engineering, and in vitro fertilization.

Given the amount of interest in these issues amongst politicians and the general public, it seems like there should be an easily accessible guide that would provide the background necessary for a layperson to understand the science behind this type of research. That was the inspiration for Christiane Nusslein-Volhard to write her book Coming to Life:

I have written this book for all those who are curious and who would like to understand the process of life a little better without having to deal with highly specialized knowledge. It is for those who encounter biology in their professional life: medical professionals, chemists, and physicists. I hope my readership will also include those who might have many questions regarding genes and embryos owing to current bio-political debates, such as philosophers, lawyers, politicians, and theologians.

The book is broken up into chapters which can be roughly categorized into background (dealing with genetics, the central dogma, and cells), development in model organisms (Drosophila development, molecular patterning, and vertebrate development), and implications (human development, evo-devo, technology, and politics). I have a hard time evaluating whether a non-biologist would be able to digest all of this material. I haven’t taken a developmental biology course in over five years, but I am still familiar with a lot of the topics. From my skewed vantage point, it appears she overshoots her intended audience — falling somewhere between appropriate for a layperson and a textbook that could be used in a college developmental biology course (probably closer to a layperson). The biggest drawback comes in the organization. Nusslein-Volhard admits that each chapter should be viewed as an independent entity, but this causes the entire book to appear disorganized. This leads me to believe that it would be hard to follow for an uninitiated reader.

For me, it was an excellent refresher of developmental biology — a topic I haven’t though much about in the years since studying it as an undergrad. The author emphasizes the importance of mRNA and protein gradients without getting bogged down in the details, and her outline of early developmental events is quite clear. But the goal of having autonomous chapters means that there really isn’t an adequate treatment of the necessary background information in the first few chapters. I consider this to be the book’s greatest limitation. Nusslein-Volhard writes that the reader should have “a basic knowledge of biochemistry” and she “presents the concepts of cell biology rather briefly.” Why, if the intent is for the book to be readable for non-biologists, would an author make such assumptions? Granted, she does provide a glossary which may be helpful to a less informed reader, but a clearer treatment of gastrulation, the structure and regulation of genes, and meiosis would probably make the book much clearer for a layperson.

My criticisms, however, should be taken with a grain of salt, as I cannot put myself in the shoes of a chemist who has never taken a college level biology course. That said, Nusslein-Volhard’s goal of providing a book that will inform members of the general public about animal development is a great idea. Understanding the concepts in this book should be a requisite for any politician or member of the general public who would like to weigh in on issues such as birth control, abortion, stem cell research, or cloning. People tend to become quite emotional when discussing these topics, but their opinion means nothing without understanding how these processes work. It’s quite refreshing that the author addresses these topics in the last chapter of her book, providing some context for why developmental biology is an important subject.

Nusslein-Volhard’s Coming to Life, along with Sean Carroll’s Endless Forms Most Beautiful is part of a growing trend of high profile researchers (specifically in the field of developmental genetics) making their work accessible to the general public. You can sense the Noble Laureate’s passion for her research in the amazing hand drawn images spread throughout the book. These illustrations alone are reason enough to check out this book.

Comments

  1. #1 Nick Anthis
    August 21, 2006

    Looks like we had pretty similar takes on the book (mine is here). As someone pretty far removed from basic genetics these days (studying protein NMR), I found it particularly informative, but it would have been a little tough without a background in the biological sciences.

  2. #2 Amit
    August 21, 2006

    You have motivated me to check this book out. I took a developmental biology 7 years ago. While I enjoyed the class, I haven’t thought much about the subject since.

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