7.
Morislav Radman and Richard Wagner, "The High Fidelity of DNA Duplication,"
Scientific American
259.2
(August 1988): 40–46.
8.
The structure and behavior of DNA and RNA are described in Gary Felsenfeld, "DNA," and James Darnell,
"RNA," both in
Scientific American
253.4 (October 1985), p. 58–67 and 68–78 respectively.
9.
Mark A. Iobling and Chris Tyler-Smith, "The Human Y Chromosome: An Evolutionary Marker Comes of
Age,"
Nature Reviews Genetics
4 (August 2003): 598–612; Helen Skaletsky et al., "The Male-Specific Region
of the Human Y Chromosome Is a Mosaic of Discrete Sequence Classes,"
Nature
423 (June 19, 2003): 825–
37.
10.
Misformed proteins are perhaps the most dangerous toxin of all. Research suggests that misfolded proteins
may be at the heart of numerous disease processes in the body. Such diverse diseases as Alzheimer's disease,
Parkinson's disease, the human form of mad-cow disease, cystic fibrosis, cataracts, and diabetes are all thought
to result from the inability of the body to adequately eliminate misfolded proteins.
Protein molecules perform the lion's share of cellular work. Proteins are made within each cell according
to DNA blueprints. They begin as long strings of amino acids, which must then be folded into precise three-
dimensional configurations in order to function as enzymes, transport proteins, et cetera. Heavy-metal toxins
interfere with normal function of these enzymes, further exacerbating the problem. There are also genetic
mutations that predispose individuals to misformed-protein buildup.
When protofibrils begin to stick together, they form filaments, fibrils, and ultimately larger globular
structures called amyloid plaque. Until recently these accumulations of insoluble plaque were regarded as the
pathologic agents for these diseases, but it is now known that the proto fibrils themselves are the real problem.
The speed with which a proto fibril is turned into insoluble amyloid plaque is inversely related to disease
progression. This explains why some individuals are found to have extensive accumulation of plaque in their
brains but no evidence of Alzheimer's disease, while others have little visible plaque yet extensive
manifestations of the disease. Some people form amyloid plaque quickly, which protects them from further
protofibril damage. Other individuals turn proto fibrils into amyloid plaque less rapidly, allowing more
extensive damage. These people also have little visible amyloid plaque. See Per Hammarström, Frank
Schneider, and Jeffrey W. Kelly, "
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