How
do gene mistakes occur?
-
Gene mutations can be either inherited from a
 parent
or acquired. A hereditary mutation is a mistake that is present
in the DNA of virtually all body cells. Hereditary mutations are
also called germline mutations because the gene change exists
in the reproductive cells (germ cells) and can be passed from
generation to generation, from parent to newborn. Moreover, the
mutation is copied every time body cells divide.
- Acquired
mutations, also known as somatic mutations, are changes in DNA
that develop throughout a person's life. In contrast to hereditary
mutations, somatic mutations arise in the DNA of individual cells;
the genetic errors are passed only to direct descendants of those
cells. Mutations are often the result of errors that crop up during
cell division, when the cell is making a copy of itself and dividing
into two. Acquired mutations can also be the byproducts of environmental
stresses such as radiation or toxins.
 Mutations
occur all the time in every cell in the body.
Each cell, however, has the remarkable ability to recognize mistakes
and fix them before it passes them along to its descendants. But
a cell's DNA repair mechanisms can fail, or be overwhelmed, or
become less efficient with age. Over time, mistakes can accumulate.
- Hereditary
mutations are carried in the DNA of the reproductive cells. When
reproductive cells containing mutations combine to produce offspring,
the mutation will be present in all of the offspring's body cells.
Acquired mutations develop in DNA during a person's lifetime.
If the mutation arises in a body cell, copies of the mutation
will exist only in descendants of that particular cell.
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