Retrotranspozisyonlar

Retrotranspozisyonlar, also known as retroviral-like elements or retroposons, are mobile genetic elements that transpose (move) within a genome through an RNA intermediate. This process, known as retrotransposition, involves reverse transcription of an RNA copy of the element into DNA, which is then inserted at a new location in the genome. This mechanism is similar to the replication cycle of retroviruses, although retrotransposons typically lack the genes necessary to form infectious viral particles.

There are two main classes of retrotransposons: those that encode reverse transcriptase and other proteins necessary for their own mobilization (autonomous retrotransposons), and those that rely on the machinery provided by autonomous elements (non-autonomous retrotransposons). Autonomous retrotransposons include LTR (long terminal repeat) retrotransposons, which are structurally similar to retroviruses and are abundant in eukaryotic genomes, and non-LTR retrotransposons, which include LINEs (long interspersed nuclear elements) and SINEs (short interspersed elements). SINEs are generally non-autonomous and rely on LINEs for their retrotransposition.

Retrotransposition is a significant source of genetic variation and can lead to mutations, gene duplications, and rearrangements within a genome. While often considered parasitic DNA, retrotransposons have also played roles in genome evolution, contributing to the development of new genes and regulatory elements. The activity of retrotransposons can be influenced by various factors, and their uncontrolled proliferation can lead to genomic instability and disease in some cases.