Mutations are permanent changes in the structure of the DNA. A mutation can range in size from as small as a single DNA base to a section of a chromosome. Mutations are not necessarily all harmful. From an evolutionary perspective, mutations can be beneficial helping us to adapt and survive over the centuries as environmental changes begin to have their impact. Mutations can be hereditary, and thus we can inherit it from our parents or take place in our life time.
Mutations occurring at some point during a person’s life can either be caused by environmental factors such as radiation or during cell division, referred to as mitosis, when genetic information is replicated in the cell nucleus. However, these mutations occurring in one’s life cannot be passed on to another individual. If a change in DNA occurs in more than 1% of the population, this is called a polymorphism, and is considered to be normal and is responsible for differences between people such as hair and eye color. In paternity DNA testing, a mutation can result in alleles that do not match between a father and child and can sometimes be misleading when interpreting results.