Chapter 3: Handy Genes

I loved reading this chapter becuase the author focused on genetics and I always wanted to study genetics in the future. In chapter three, Shubin continued to explain the discovery for Tiktaalik and how the anatomy of humans are related to those of animals; I was not excited to read a repetitive chapter until i read about Shubin's colleague, Randy Dahn. It was interesting to learn that the "DNA have enormous potential to reavel the inner fish" (45). Starting with a single cell that contains DNA, specialized cells organize themselves to compose the right parts of the body. I was fascinated by the work of individual's DNA. Reading about the scientists, Zwilling, Saunders, and Gasseling, i was shocked their discovery with the chicken egg: "A strip of tissue at the extreme end of the limb bud is essential for all limb development" (49) and "If you supply the vitamin A at the right concentration and the right stage, you'll get the same mirror-image duplication[...]" (50). I also learned that in every limbed animal, sonic hedgedog is active in the ZPA tissue, for the DNA recipe to build the arm is identical in animals with limbs. I didn't like how Shubin concluded the chapter with the idea that animals and human are similar but i look forward to reading chapter four!