The Difference Between Point and Frameshift Mutations

Video Transcript

The DNA in our cells is the blueprint for making RNA, which is then translated into making the proteins that drive many of the functions in our bodies.

Proteins are present in all living organisms and do things such as, providing flexibility and rigidity to a cell, delivering oxygen to the muscles, transporting bodily fluids, and making antibodies that fight diseases.


As we look closer, we see that proteins are made up of smaller units called amino acids. For every protein, a unique set of amino acids are connected in a chain that is coded for by the DNA. As DNA is copied to make RNA, a very specific sequence of instructions, called bases, are written in sets of 3’s. Bases are the specific information used to dictate which amino acid is being coded for. There are 4 bases that make up RNA which are, uracil, cytosine, adenine and guanine, we’ll represent them with the letters U, C, A and G. The order of these bases directs how the amino acids line up, when they start, when they stop, and determines how long the chain will be. So, what happens when things go wrong? When errors occur in the DNA code, it is referred to as a mutation. The two main types of mutations are point mutations and frameshift mutations.


A point mutation is where one of the three bases, is replaced with a different base. Sometimes, these mutations have minimal effect, but other times they can significantly alter the structure of the protein depending on how different the new amino acid is from the original. The new base may also alter the protein by creating a stop signal too early in the amino acid chain. Mutations like this often render the protein completely ineffective.


A frameshift mutation happens when one or more of the bases are inserted or deleted. Since bases are read in groups of 3, their addition or deletion in anything other than multiples of 3 disrupts the reading frame sequence. When this happens, the entire code following the addition or deletion will be read incorrectly. This could result in the wrong amino acid being coded, thereby changing the protein’s shape and function.


Whether the errors occurred in the DNA blueprint, or in the RNA copy, Caris can help your doctor determine where the mutation happened by testing all of your bodies DNA, RNA and proteins. Knowing all of the mutations present in your tumor can shed light on how the cancer may behave, and what treatments will be most effective. Ask your doctor about Caris testing.

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Patient Education Videos

The Central Principles of Molecular Biology video series is meant to help explain molecular profiling and cancer, so that you can understand how Caris molecular profiling helps fight cancer through precision oncology.