Chapter 3: Handy Genes

First off, I thought the title of this chapter was clever. I was really confused though. I understood the fact that numerous genes are "turned on and off" during development. I understood the patch of tissue called the ZPA and its function and why it was so important, but when Shubin started unraveling the details and experiments of ZPA, I was totally lost. I read Mr. Tisor's disclaimer about this chapter and its complexity and it's true... This chapter was a bit difficult for me. I had to go back and re-read about the genetic experiments of a fly's wing, hedgehog, and Sonic hedgehog.

After re-reading it, I grasped the concept that Shubin was trying to emphasize. DNA is pretttty important. Not only is DNA important, but hedgehog was found in sharks. That section about the experimentation of the sharks and the results fascinated me. How could a species that is vastly different from chicken or mice produce the same results as them? That's so amazing. This proves that connections between animals and other species cannot be judged solely on their appearance. The phrase, "Dont judge a book by its cover" applies to these experiments on limbs and fins. As Shubin said, "The connections among living creatures run deep." Thank you, DNA.