chapter eight

I agree with everyone that this chapter was short but it was just as informative as all the other chapters and again like all the others before it, this chapter surprised me with finding out new things about anatomical history especially when Shubin explains "The genes involved in the sense of smell are present in all of our cells, although they are active only in the nasal area" (140). Then later he adds, "we mammals, with over a thousand of these genes, devote a huge part of our entire genetic apparatus just to smelling... fully 3 percent of our entire genome is devoted to genes for detecting different odors" (144). 3 percent is quite a significant percentage for only one of our senses, more so, for something that helps us survive yet we take for granted.

I didn't know that the sense of smell even had a connection with genetic apparatus. But reading this chapter reminded me of an article I read in a magazine that explained new studies that prove the loss of smell as an early symptom of Alzheimer's disease. Patients that were not able to identify unique, distinct odors/aromas such as cinnamon and vinegar were more likely to get Alzheimer's disease than those who were able to identify the smells, yet in consideration with the family history of the patient and if passed generations in the family had it as well. The sense of smell is so powerful that it can do so much from evoking memories, to predicting disease patterns through generations, down to the very survival of our kind.

At the end of the chapter Shubin states how Gilad found "that primates that develop color vision tend to have large numbers of knocked-out smell genes... We humans are a part of a lineage that has traded smell for sight... In this trade-off, our sense of smell was deemphasized, and many of our olfactory genes became functionless" (147). This made think: Do color-blind people have more genes for smell as a compensation since their bodies have traded colored sight for smell? Maybe not necessarily... idk

Alexis Jacalne