recombinant structure (rus. рекомбинантная структура) — a hybrid (recombinant) nucleic acid (DNA or RNA) or protein obtained by combining foreign fragments in vitro and containing new combinations of sequences of nucleotides or amino acids, respectively.

Description

Recombination is the exchange of genetic material by breaking and rejoining different nucleic acid molecules, i.e., the redistribution of genetic material resulting in new gene combinations. In vivo recombination in eukaryotes involves the exchange of chromosomal segments during cell division. Recombination in prokaryotes is achieved by DNA transfer through conjugation, transformation or transduction, or through the exchange of viral genome segments. Genetic engineering has greatly expanded the possibilities of recombination exchanges and makes it possible, in contrast to natural recombination, to obtain hybrid molecules of nucleic acids containing virtually any foreign fragments. The essence of this technology lies in the combination of DNA fragments in vitro followed by the insertion of recombinant genetic structures into living cells. Genetic engineering became possible after the discovery of restrictases (enzymes that cut DNA at a specific site) and ligases (enzymes that join together double-stranded DNA fragments). These enzymes are used to obtain the desired DNA fragments and then to combine them into a single molecule. This artificial combination is made regardless of DNA origin, whereas in nature the combination of genetic information from unrelated organisms is prevented by interspecies barriers. The first recombinant DNA molecule, consisting of a DNA fragment of SV40 virus and lambda bacteriophage with E. coli galactose operon, was created by Berg and co-workers in 1972.

The genetic engineering technique involves several steps:

1. Selecting the desired (target) gene;

2. Inserting it into a genetic element capable of autonomous replication (vector);

3. Introducing the vector into the recipient organism;

4. Identifying (screening) and isolating cells that have acquired the desired gene or genes.

Proteins obtained by genetic engineering, i.e. those that resulted from the expression of recombinant DNA, are also called recombinant proteins. Recombinant DNA technology has had a significant impact on the development of modern biology, allowing the solution of many theoretical problems, for example, determining the functions of proteins, and studying the regulation of gene expression. The construction of recombinant structures was used to discover and study: mosaic gene structure in higher organisms, bacterial transposons and mobile dispersed genetic elements of higher organisms, oncogenes, etc. Recombinant structures are widely used in industrial biotechnology, including the production of enzymes, hormones, interferons, antibiotics, vitamins and many other products for pharmaceutical and food industries, which previously were very time consuming and expensive. Recombinant DNA technology was used to create genetically modified plants and transgenic animals with new useful features. Recombinant structures are used in medicine for gene therapy, diagnostics and recombinant vaccines.

Illustrations

Genetic recombination diagram: recombination occurs due to physical discontinuity in chromosomes

Genetic recombination diagram: recombination occurs due to physical discontinuity in chromosomes (M) and (F) and their subsequent combination to form two new chromosomes (C1 and C2).


Authors

  • Naroditsky Boris S.
  • Shirinsky Vladimir P.
  • Nesterenko Lyudmila N.

Sources

  1. J. Sambrook et al. Molecular Cloning: A Laboratory Manual. — Cold Spring Harbor Laboratory Pr, 1989, 1659 P.
  2. Genetic engineering / edited by A. A. Baeva. Itogi nauki i tekhniki. Ser. Molekuljarnaja biologija. V. 12, P. 1–2. — Moscow., 1979–80.
  3. James D. Watson et al. Recombinant DNA: a short course. — Scientific American Books, 1983 — 260 p.

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