|
Medical Definition of DNA insertion elements
1. Discrete transposable segments of DNA which can insert into chromosomal, phage, and plasmid DNA. Some insert at random while others are site-specific; most have not been found to exist except in the inserted state. Their insertion into a genome always produces a mutation ("insertion mutation"), and their excision frequently results in a loss of host genetic information. Types of transposable elements include is elements (insertion sequence elements), which are composed of between 700 and 1400 bases and contain no genes unrelated to insertion function and tn elements (transposon elements), which are generally larger than 1400 bases and contain genes unrelated to insertion function. The concept also includes the delta element of saccharomyces cerevisiae and the integration site. (12 Dec 1998)