Chapter 3: Handy Genes

It is interesting to see that what a scientists injects into the embryo and when they inject it produce different results. It doesn't seem like anything significant but it makes a huge difference. Even tissue that seems to be insignificant due to its size, can determine whether or not a chick will have limbs in certain places. It was also interesting to read about ZPA especially because excess ZPA could make a pinky and a thumb even for a bird. For me, ZPA didn't seem to be very significant but it turns out that it controls the formation of fingers and feet. It was jocular to read that Tabin, McMahon and Ingham named the chicken version of the gene "hedgehog," Sonic hedgehog. I always thought that there were complicated scientific names for everything but seeing that a gene was named after a video game, that isn't always the case
This chapter was especially interesting to me because I had always wondered how some people were born with extra fingers. I can't believe that without Sonic hedgehog you would have extra fingers or your pinky and thumb would look alike. When I read about Randy injecting a Sonic hedgehog protein from a mouse into a skate, I was intrigued. The results were outside of my expectations. I guess it really is true that there are connections among living creatures despite whether or not the creature in question is fish, bird, or mammal.