AP Bio: Genome Chromosome 4: Fate

In the "Chromosome 4: Fate," Matt Ridley begins the fourth chapter of Genome by talking about how most genes are named and identified with the diseases they cause.  He introduces Chromosome 4 as "the most famous of all the 'disease' genes" (55), as it is associated with the disease Huntington's chorea, which is caused by the mutated version of the gene.  If this gene is not present, it causes Wolf-Hirschhorn syndrome.  The gene repeats the "word" CAG over and over again.  If it is repeated thirty-nine times or more, in mid-life, you will lose your balance, have jerking limbs, deep depression, hallucination, and delusions for about 25 years and eventually die.  There is no cure for the disease and being diagnosed with the disease and waiting for it to strike is likely worse than just being ignorant about it.  When the scientist Nanacy Wexler was deciding whether to take the test to see if she had the disease, she compares science to Tiresias, the blind seer of Thebes, who had the gift of foresight but could not change the future, implying that for people like her who have a high chance of having the disease, "[their] fate is in [their] genes."


Source: Genome: The Autobiography of a Species in 23 Chapters by Matt Ridley