Käänteiskopiointi

Käänteiskopiointi, or reverse transcription, is a biological process where an RNA molecule is used as a template to synthesize a complementary DNA (cDNA) molecule. This process is primarily carried out by a specialized enzyme called reverse transcriptase. In nature, reverse transcription is famously observed in retroviruses, such as HIV. These viruses use reverse transcriptase to convert their RNA genome into DNA, which is then integrated into the host cell's genome.

This mechanism is crucial for the replication cycle of retroviruses, allowing them to hijack the host cell's machinery for their own purposes. Beyond viruses, reverse transcription also occurs in eukaryotic cells as part of the life cycle of retrotransposons, which are mobile genetic elements. These elements can copy themselves and insert into new locations in the genome, contributing to genetic diversity and evolution.

The discovery of reverse transcriptase and the process of reverse transcription by Howard Temin and David Baltimore in the late 1960s and early 1970s revolutionized molecular biology. It challenged the central dogma of molecular biology at the time, which proposed that genetic information flows only from DNA to RNA.

In molecular biology laboratories, reverse transcription is a fundamental technique used to study gene expression. Researchers use it to create cDNA libraries from mRNA, which represent the genes that are actively being transcribed in a cell or tissue. This cDNA can then be used for various downstream applications, including gene cloning, sequencing, and gene expression analysis. The ability to convert RNA into DNA has opened up vast possibilities for understanding biological processes and developing new diagnostic and therapeutic tools.