Chapter 3: Handy Genes

Unlike the past few chapters, this chapter provided some scientific explanations behind the genes of certain organisms and for me, it was very interesting. Starting off with Randy Dahns's experiments, I first wondered why Shubin was explaining this DNA change in the chicken eggs. But as he went further on, I realize that this change in DNA through the retinol injection creates a specific reaction in the products, for example, duplicating the arm bones. After I read this, I was amazed at how a simple change can result in a drastic modification. And I never thought something like vitamin A would deform a organism into having duplicated arms! Moreover, the ZPA was another topic of interest for me. That particular tissue exists in so many creatures and the funny thing is that the location is same for all of them. I was really surprised that all the organisms discovered by the scientists had the same ZPA in the same locations. This really shows Shubin's point in that these organisms all share certain characteristics. Especially when the sonic hedgehog came out in the book, I was chuckling by myself. Scientists naming their discoveries based on sega video game was unusual; I wonder if they were game nerds in the past.