Molecular Biology of the Gene



All living things carry a molecule that provides the blueprint for the traits they express. Deoxyribonucleic acid, otherwise known as DNA, is a molecule found inside the cells of every organism. When the organism grows, the DNA replicates itself so that each new cell created has an identical copy of the genetic information. Sometimes errors occur during DNA replication, which can result in new traits. The DNA is often able to repair itself and the code gets passed on as usual. However, sometimes the mistakes are irreversible and these errors become inherited. These new traits are the basis of evolution—if the trait is beneficial to the organism, it will be passed on to future generations.

At A Glance

  • DNA provides the blueprint for all traits an organism possesses. The structure of DNA serves to determine which traits are expressed.
  • DNA has two complementary strands that form a double helix.
  • DNA replicates itself before cells divide.
  • Errors can occur during DNA replication.
  • Several types of mutations can lead to the formation and expression of new traits.
  • A mutation may cause a loss of function, a gain of function, a reversion to a previous state, a change only under certain conditions, or no change at all.
  • Mutations may be point mutations or chromosomal mutations.
  • Mutations can have harmful or beneficial effects on organisms. Mutations are essential to evolution.