SOS Chap 6 summary

     Chapter 6, Survival of the Sickest was about viruses. It explained how viruses are master mutators that have the potential to create the successful genetic patterns that underlie all living cells and have helped humans evolve into complex organisms much faster than we would have on our own. Viruses are not living organisms and hijack, infect the host cell injecting DNA or RNA retroviruses. The chapter talks about vaccines that have protein coats and create white blood cells when recognizing invaders. The chapter talks about the first vaccine that gave protection against smallpox with cowpox infection. I learned that less than 3% of your DNA contains instructions for building cells, and that a third of your DNA is derived from viruses. Scientists initially believed most of the DNA was "junk DNA" because it was not directly responsible for making proteins, but it actually is "non-coding DNA" which may have provided the code for our evolution up and away from our ancestors and viruses may have infected us with that code. Humans have a total of approximately 25,000 genes. An important topic was the role of jumping genes, also known as transposons, in brain development and the immune system. These jumping genes are probably descended from viruses. The more complex an organism is, the more jumping genes it has.  Jumping genes are similar to "inherited- RNA acquired traits." These genes hump to find a mutation best fit for the environment. The author also gives a brief description of how antibodies are built. Body building follows a general path of DNA to RNA to protein. The chapter discusses retroviruses and how at least 8% of the human genome is composed of retroviruses. Retroviruses are made of RNA and use an enzyme called reverse transcriptase that transcribe itself from RNA to DNA, reversing the information flow by copying and pasting into host DNA. Our genomes have been modified by one particular retrovirus in a way that makes it easier for us to be infected by other retroviruses and allowing more rapid mutation and faster evolution. I learned variations are caused by mutation and viruses cause a change in physical traits.