Mutations are errors made in the DNA sequence than can have negative side effects, no effect, or positive effects for an organism

Can We Help with Your Assignment?

Let us do your homework! Professional writers in all subject areas are available and will meet your assignment deadline. Free proofreading and copy-editing included.

Point Mutations

Mutations that occur at a certain point in the DNA

Substitution – the replacement of one base in a DNA sequence by another base

Deletion – the elimination of a base pair or group of base pairs from a DNA sequence

Insertion – the placement of an extra nucleotide in a DNA sequence

Substitution Errors:

Silent mutations:

– a mutation that does not result in a change in the amino acid coded for and, therefore, has no effect on the operation of the organism

– could be an error in an intron or in the 3rd base pair of a codon

Missense mutations:

– a change that leads to a different amino acid being placed in the protein sequence

– will cause a change in protein conformation (shape) à may be bad or may have no affect

Nonsense mutations:

– a change that causes a stop codon to replace a codon for an amino acid

– translation stops prematurely -> produces nonfunctional proteins ->often lethal

Insertion/Deletion Errors:

Frameshift mutations:

–  caused by the insertion or deletion of one or two nucleotides in the DNA sequence

– drastic errors; can result in many different amino acids substituted or a stop codon read normal amino acid sequence:

Central Dogma of Biology

Chromosomal Errors

A translocation is the transfer and exchange of a fragment of DNA between two nonhomologous chromosomes

– if they happen to fall within a coding region of a gene, they will disrupt the correct transcription of the gene

An inversion is a chromosomal segment that has reversed it’s orientation in the chromosome causing the gene to be disrupted

Causes of Genetic Mutations

Spontaneous mutations – mutations caused by errors in DNA replication or crossing over in meiosis

Induced mutations – mutations caused by mutagenic agents like UV radiation, cosmic rays, X rays, and certain chemicals

Cite this article as: William Anderson (Schoolworkhelper Editorial Team), "DNA Mutations," in SchoolWorkHelper, 2019,
Inline Feedbacks
View all comments