Chapter 3: Handy Genes

"Handy Genes" was the most interesting and entertaining chapter to read so far. Although there were many confusing bits that I did not quite understand, the concept of genes still grasped my attention. My focus was immediately drawn to the title of the chapter because I have always been interested in the history of genes and DNA.

In this chapter, the most fascinating discovery was the "ZPA" (Zone of polarizing activity). It was interesting to find out the significance and function of the ZPA. The diagram on page 50 of the "ZPA" has helped me understand how it looked like inside a wing and what it worked for. I would have never found out that such a small patch of tissue could be responsible for differentiating a pinky to a thumb. What made it more interesting was that in 1979, Denis Summerbell tested a concentration-dependent idea in which he placed a small piece of foil between the ZPA patch and the rest of the limb. It was shocking to see that the cells on the ZPA side formed digits while the cells on the opposite side did not.

-Stacey Kim