Chest pain is always an alarming symptom since it usually raises the fear of heart disease. And because chest pain may indeed be a sign of angina or of some other heart problem, it is always a good idea to have it checked out. But heart disease is only one of the many types of conditions that can produce chest pain.
Concept 27 Mutations are changes in genetic information. Hermann Muller received the 1946 Nobel Prize in Physiology or Medicine for his work on mutations induced by X-rays. Seymour Benzer used genetics to prove that mutations were caused by changes in the DNA sequence.
In 1871, the mention of a âwarm little pondâ by Darwin may be considered as the first mention of this hypothesis. Subsequently it was more clearly formulated by Oparin (1924), Haldane (1929), and Urey (1952), ideas which ultimately led to the Miller experiment (1953).