In Molecular biology, an insert is a piece of DNA that is inserted into a larger DNA vector by a recombinant DNA technique, such as ligation or recombination. This allows it to be multiplied, selected, further manipulated or expressed in a host organism.
Inserts can range from physical nucleotide additions using a technique system or the addition of artificial structures on a molecule via mutagenic chemicals, such as ethidium bromide or crystals.
Inserts into the genome of an organism normally occur due to natural causes. These causes include environmental conditions and intracellular processes. Environmental inserts range from exposure to radioactive radiation such as Ultraviolet, mutagenic chemicals, or DNA viruses. Intracellular inserts can occur through heritable changes in parent cells or errors in DNA replication or DNA repair.
Gene insertion techniques can be used for characteristic mutations in an organism for a desired phenotypic gene expression. A gene insert change can be expressed in a large variety of ends. These variants can range from the loss, or gain, of protein function to changes in physical structure i.e., hair, or eye, color. The goal of changes in expression are focused on a gain of function in proteins for regulation or to termination of cellular function for prevention of disease. The results of the variations are dependent on the place in the genome the addition, or mutation is located. The aim is to learn, understand, and possibly predict the expression of genetic material in organisms using physical and chemical analysis. To see the results of genetic mutations, or inserts, techniques such as DNA sequencing, gel electrophoresis, immunoassay, or microscopy  can observe mutation.