discuss evidence for the mutagenic nature of radiation
There is much evidence for the mutagenic nature of radiation. Environmental factors that may increase the rate of mutation include X-rays, radiation from atomic bombs and ultraviolet light.
A mutagen is a natural or human-made agent (physical or chemical) which can alter the structure or sequence of DNA. Mutagens can be carcinogens (cancer causing) or teratogens (birth defects causing).
Radiation was the first mutagenic agent known. Its effects on genes were first noticed in the 1920′s.When X-rays were first discovered, they were thought to be harmless and were a great novelty. You could even buy an “X-ray machine” for your home for entertainment. Most of the first generation of scientists who worked with radiation died of cancer. Famous examples are Marie Curie and her daughter who both died of leukaemia.
Hans Muller received the Nobel Prize in 1927 for showing that genes had the ability to mutate when exposed to X-rays. Beadle and Tatum used X-rays to produce mutations in bread mould in the formulation of their “one – gene one – polypeptide” hypothesis.
The atomic bombs dropped on Hiroshima and Nagasaki also increased the evidence for mutations caused by radiation. There was a tenfold increase in cancer deaths directly after the bombs were dropped.
Mutagens may cause death in the individual but unless they affect the sex cells the effect is not passed on to the next generation.
Sites with more information:
Mutation, Mutagens, and DNA Repair Kansas State University, USA
Mutations Professor John Blamire, Science at a Distance, Brooklyn College, City University of New York, USA
How does radiation effect humans? ACHRE Report, Department of Energy, USA