Ch.3: Handy Genes

In this 3rd chapter of Shubin's book what grabbed my attention most was when Shubin says, "A strip of tissue at the extreme end of the limb bud is essential for all limb development. Remove it, and development stops. Remove it early, and we are left with only an upper arm, or a piece of an arm." What Shubin is saying is that these small two little patches of tissue play such a critical role in our limbs that it can stop development completely. It was amusing to see how such a small part of our body can be the most important. It is also laudable that Shubin brought up the study of chicken eggs brings us to the discovery of the ZPA gene, which further led to the discovery of the Sonic hedgehog. Through this chapter I was also able to learn that the DNA "recipe" to build our arms is identical to basically any creature that has limbs. As I continue to read through these chapters, I began to notice a redundant conclusion that Shubin has always come to: we are all similar. In each chapter as we learn something new, Shubin explains to readers how we humans are similar to other living creatures. However, I still seem to question this idea of the gradual change of transformation from fish to humans. I often wonder while reading this book that just because we possess similar traits with other creatures does not entirely mean we were once the same organism. However, as i gain more insight by each chapter I look forward to what more Shubin has to offer to us readers.