Genome Summary #4 Chapter 4 Fate

In Chapter 4 Ridley compares identifying genes by the diseases that they can cause to identifying organs by the disorders they can suffer in order to show the differences of a gene and a mutation. For example, the Wolf- Hirschhorn is when individuals with the gene are healthy and those without the gene have Wolf- Hirschhorn syndrome and those with the mutated gene have Huntington's chorea. In 1993 the gene that was responsible for the mutation for Huntington's disease was found and it carried a repetition of the codon CAG. The number of repetitions tells what age the carrier gets the symptoms. When excess CAG repeats, five other neurological disorders and twelve known human diseases can occur. In sperm production the number of repetitions can increase over time.