Genetic Engineering and Biotechnology: Advances and Applications
Genetic Development and its Mechanisms
Genetic development has made it possible to decipher the rules governing developmental processes, such as the transformation of a fertilized ovule into an adult organism. Two Spanish scientists have helped to establish the genetic basis of this field. One of their discoveries was how animals are built in a modular form: they discovered compartments in which certain selector genes are expressed exclusively.
The development of an organism involves an initial cell multiplying (proliferation: requiring cell division and, therefore, replication of its genome). Then, the cellular daughters specialize to form different tissues (differentiation: requiring the regulation of gene expression so that some genes are expressed and not others).
Epigenetics
Epigenetics is the branch of genetics that studies characteristics of an individual that are not determined by the nucleotide sequence of DNA. For example, the degree of coiling of chromatin influences the transmission of the DNA sequence. If a piece of DNA is very coiled, the synthesis of certain proteins will be inhibited. Besides, some molecules can adhere to DNA atoms, inhibiting gene expression and influencing protein formation. Molecules included in the cytoplasm and cellular proteins also influence protein synthesis in the ribosome.
Antigenetics and Biotechnology
Antigenetic technologies, such as medicine, save genotypes that would otherwise succumb to natural selection. Forty years ago, the basic machinery of life was understood, and genes were re-examined. The day came when DNA, the essence of life, could be manipulated. Thus, biotechnology and genetic engineering were invented.
Tools for Manipulating DNA
- Restriction enzymes: Capable of cutting specific DNA sequences.
- DNA ligase: Can join DNA fragments that have been cut.
- Plasmids: Small circular DNA molecules living inside bacteria, used as vehicles or vectors in genetic engineering.
It was discovered how to introduce plasmids inside the bacterium Escherichia coli, a process named transformation. Herb Boyer and Stanley Cohen first introduced genetic information within a bacterium to produce human proteins.
Advances Thanks to Biotechnology
Thanks to biotechnology, it has been possible to make human insulin. There are also human interferon (for sclerosis treatment), growth hormone, and lipase (an enzyme efficient against dirt), and chymosin for cheese production.
The Polymerase Chain Reaction (PCR)
The polymerase chain reaction (PCR) is a technique that has played an essential role in genetics, invented in 1986 by Kary Mullis. The technique can rapidly amplify DNA samples; that is, an appreciable amount of DNA is obtained from a very small sample.
Stem Cells
Stem cells are undifferentiated cells likely to convert into other kinds of tissue, such as cardiac or skin cells. Types include embryonic stem cells, those from the umbilical cord, and induced stem cells. Viruses are used to introduce the genetic material needed to transform a cell; these viruses become very efficient at integrating their genetic material into the host DNA, allowing for modification.
Molecular Medicine and Gene Therapy
Genetic engineering has allowed the development of molecular medicine, which, in addition to developing very potent diagnostic methods, is enabling gene therapy, aimed at achieving a definitive cure for hereditary diseases. This involves introducing the correct gene into the patient’s body to fix deficiencies in their genome. A normal gene is identified and introduced into the patient’s cells to replace a defective one.
Forensic Genetics
Genetic engineering has also allowed for forensic methods for the identification and exclusion of criminals. Genetic traces are based on the comparison of regions of the genome that are often highly repetitive and have a sequence that is unlikely to match in two individuals. This is used for paternity testing and identifying bodies.