A change to genetic material is called a mutation , and it means the DNA (or RNA in some viruses) sequence has been altered.

Basic idea

When you are asked “what change to genetic material do you observe?”, the answer is usually describing what kind of mutation has happened. Common possibilities include:

  • A base has been swapped for another (substitution).
  • One or more bases have been removed (deletion).
  • Extra bases have been added (insertion).
  • A larger stretch of DNA has been duplicated, inverted, or moved (chromosomal alteration).

Common mutation types

If you are looking at a specific DNA sequence or diagram, these are the main named changes you might be expected to state.

  • Point mutation : One nucleotide is changed (substitution).
  • Silent / missense / nonsense : Special cases of point mutations that change the amino acid a little, not at all, or into a stop codon.
  • Frameshift mutation : An insertion or deletion that is not a multiple of three bases, shifting the reading frame.
  • Chromosomal mutation : A larger-scale change such as deletion, duplication, inversion, or translocation of big DNA segments.

If you can share the exact sequence or picture you are looking at, a more precise one-line answer (for example, “a substitution mutation” or “a frameshift due to a deletion”) can be given.