chromosome abnormality in which material from one chromosome is inserted
into another nonhomologous chromosome; a mutation in which a segment of DNA
is inserted into a gene or other segment of DNA, potentially disrupting the
Definition from: GeneReviews
from the University of Washington and the National Center for Biotechnology Information
Insertion is a type of mutation involving the addition of genetic material. An insertion mutation can be small, involving a single extra DNA base pair, or large, involving a piece of a chromosome.