Evolution of genetic engineering Dr. Mohammed Mabrouk Salama
The world is currently witnessing many revolutions that have either positive or negative effects on the human environment and the vital environment around it. Among these revolutions that have a great impact on human life is the revolution in the field of biology. This revolution, which emerged as a result of the discovery of the genetic material DNA
Since the discovery of the structure of DNA by Francis Crick and James Watson, science has developed in a very large way and developed until we reached the stage of knowing the molecular basis for the processes of DNA replication and duplicated. In the mid-seventies witnessed the birth of genetic engineering
Like any science in its infancy, it faced many reservations and doubts from many scientists, but with the passage of time these reservations and doubts began to disappear little by little.
There is a very famous saying that scientists always repeat, which is “In science what can be done will be done.” The production of insulin by cloning was the result of activating certain genes inside the body, as well as the production of milk similar to mother’s milk, preserving rare species of animals, increasing plant productivity and overcoming the problem of global food shortages, cultivating plants at a time other than their original places.
The first genetic engineering company
Genetic engineering represents the direct modification of DNA by humans, and it began since the 1970s. The term "genetic engineering" was first used by Jack Williamson in 1951 in his science fiction book (Dragon Island), then the two scientists Alfred Hershey and Martha Chase came to confirm the role of DNA in genetics
Subsequently James Watson and Francis Crick showed that the DNA molecule has the double helical structure. In 1972 Paul Berg created the first recombinant DNA molecules by mixing DNA from a monkey virus with a lambda virus
In 1973 Herbert Boyr and Stanley Cohen created the first genetically modified organism by inserting antibiotic resistance genes into the plasmid of bacteria and then Rudolf Jansch announced the creation of a genetically modified mouse by inserting foreign DNA into the embryo of a mouse, making the first newborn mouse in the modified animal world genetically
This achievement has led to concerns in the scientific community about the potential dangers of genetic engineering.
The development and hope for genetic engineering led to the establishment of the first genetic engineering company in 1977 under the name (Genetech), and in the same year this company announced the production of the first human protein by bacteria, the brain hormone Somatostatin, a peptide hormone that regulates the endocrine system and affects the Neurotransmission and cell growth by interaction with a C-protein-coupled receptor and inhibition of multiple secondary stimulatory hormones. Somatostatin has two active forms that result from the cleavage of a single protein: the first is made of 14 amino acids and the second is 28 amino acids.
human insulin production
In 1982, the first human insulin production factory was established in Liverpool, England. Since then, very high hopes have been placed on genetic engineering in the possibility of curing genetic diseases, and even the products of genetic engineering have become very promising.
The number of chromosomes in an organism
Each organism is characterized by a specific number of chromosomes inside the somatic cells, this number is fixed in the members of one species and varies from one type to another.
For example, the number of chromosomes in the worm Ascaris megalocephala has one pair of chromosomes, while this number reaches 1600 chromosomes in the radial animal Aulacantha, and in humans the number of chromosomes is 46 chromosomes (23 pairs).
Classification of chromosomes
Most of the chromosomes are found in the somatic cells of an organism, and these chromosomes may differ in size from each other, and there are sex chromosomes, which are one pair of chromosomes bearing the number 23 in humans, and this pair is responsible for determining sex in humans.
The size, shape and number of chromosomes vary according to the type of organism. Studies have shown that its length ranges between 1-30 micrometers, sometimes reaching 2 millimeters. The Y chromosome is devoid of genes except for the genes responsible for the formation of the testicles.
Genetic engineering techniques
1- Hybridization of nucleic acids: DNA can be hybridized by raising its temperature to 100 degrees Celsius, where the hydrogen bonds linking the nitrogenous bases in the DNA molecules are broken, so that each free strand becomes single and at the same time unstable, each waiting for the opportunity to pair with the other strand, when lowering Temperature Each single strand resorts to binding with another strand to form the double strand of DNA again. The amount of adhesion is determined by the temperature needed to separate the two strips from each other.
It is possible to produce a hybrid helix from single strands of DNA or RNA when mixing nucleic acids from two different types of organisms and then raising the temperature of the mixture to 100 degrees Celsius until the strands separate from each other and then cooling again so that the original and hybrid double helixes are formed, and this DNA can be used Hybrid in
- Detection of a gene in the genetic content.
- Identify the presence of the gene and the number of copies of it in the mixture.
- Knowing the evolutionary relationship between different species by measuring the similarity of nucleotide sequences in DNA, as well as the greater the cross-breeding between them indicates the closeness in the degree of kinship.
Dr. Mohammed Mabrouk Salama Professor of physiology
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