Chapter Three: Handy Genes

In my opinion, learning about genes is one of the most intriguing experience yet. This chapter not only involved Shubin's insights and experiments, but also the knowledge of several other scientists including Edgar Zwilling, John Saunders, and Mary Gasseling. Through Gasseling's experiment, I discovered that if a little patch of tissue developed too early or was transplanted in a wrong place, the result can be surprising. For example, I was shocked that a slight mistake can cause a chick to grow a full set of digits, which at the same time, gave me a nightmarish thought. I was also amazed that Sonic Hedgehog plays a crucial role in forming human limbs. Shubin states that "If Sonic hedgehog hadn't turned on properly during the eighth week of your own development, then you either would have have extra fingers or your pinky and thumb would look alike." After reading this, I was so relieved to have normal fingers and that my Sonic hedgehog worked properly. It was astonishing to know that despite their dissimilar appearance, all appendages are built by similar kinds of genes.