Five factors that can damage or destroy DNA are:
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Exposure to UV Light: Ultraviolet (UV) radiation from sunlight or other sources can cause DNA damage, particularly the formation of thymine dimers, which distort the DNA helix and can lead to mutations or cell death. This is a common cause of skin cancer.
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Mechanical Shearing: Rough handling of DNA samples, such as vigorous pipetting or vortexing, can physically break the DNA strands, rendering them unusable for analysis. This is a significant concern in molecular biology labs.
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Exposure to Chemical Agents: Certain chemicals, such as phenol used in some DNA extraction methods, can oxidize DNA bases, particularly guanine. This oxidation alters the structure of the base and can lead to mutations or strand breaks. Other examples include reactive oxygen species and certain toxins found in cigarette smoke.
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Dessication (Dehydration): Extreme dryness can damage DNA by causing strand breaks and other structural alterations. This is particularly relevant for the preservation of ancient DNA samples.
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High Temperatures: Elevated temperatures can denature DNA, causing the double helix to separate into single strands. This makes the DNA non-functional and prevents its replication. The precise temperature at which denaturation occurs depends on several factors, including the DNA sequence and salt concentration.
The provided text mentions several additional factors that can damage DNA, including jet fuel, mold, and fire (as seen in the aftermath of the World Trade Center attacks). These examples highlight the diverse environmental factors that can compromise DNA integrity. The text also mentions that BRCA proteins play a crucial role in DNA repair, and that damage to these proteins can lead to increased susceptibility to cancer.
