Genetyczne elementy ruchome u roślin i innych organizmów

In this review the types of mobile genetic elements in prokaryotes and eukaryotes are presented. There is also information about their molecular characteristics, mechanisms ofmoving, evolution and their influence on genome structure and gene activity in organisms of plants, insects and humans. Transposable elements are abundant in genomes of lower and higher organisms. Mobile genetic elements are divided into two main groups: transposons and retrotransposons. The transposons, or "jumping genes" are fragments of DNA capable of moving, from a plasmid to another plasmid (or chromosome) in prokaryotes, and from one part of a chromosome to another (or to another chromosome) in eukaryotes. Transposons become transposed directly fromDNA to DNA eg. the Ac element of maize and the P element of Drosophila are similar to bacterial transposons. Retrotransposons accomplish transposition via an RNA intermediate that is reverse transcribed before integration into a new location within the host genome. They are ubiquitous in eukaryotes and constitute amajor portion of the nuclear genome in humans, animals and plants. They are dispersed as interspersed repetitive sequences through out the genome. Retrotransposons can be divided into two sub-groups: viral retrotransposons eg. Ty (yeast), copia (fruit fly), Bs1 (maize), LINEs (mammals), Cin4 (maize) and non-viral retrotransposons which comprise SINEs and processed pseudogenes. The properties of the genetic mobile elements have been exploited as genetic tools for plant genome analysis.