The discovery of microscopic molecule containing coded information of life, it led to catching many criminals and made possible the emergence of paternity tests and not only that...
* The unknown story *
It all started with Gregor Mendel, a Czech monk considered the father of genetics. The experiment he accomplished in 1857 on peas, that provided the information key about heredity, how it inherit traits from one plant to another (much later were called genes) and increased the interest in the study of genetics. But his work has remained in the shadows for nearly a century. Isn't was him to discover the DNA, it was the American biologist James Watson with English physicist Francis Crick, which in recent history is recording as the authors of giants performance. The molecule was isolated at the beginning of the second half of the nineteenth century from the Swiss chemist Friedrich Miescher. In 1869 the scientist concerned about white blood cells found a microscopic substance in the pus collected from surgical bandages, which he called nucleated. Later, he isolated a sample of what we now call DNA from salmon sperm, and in 1889, his student Richard Altmann called it nucleic acid. The substance in question exists only in chromosomes. In the first half of the twentieth century, the principles of genetic inheritance enunciated by Mendel a century ago finally were accepted, however, the chemical nature of heredity remained unknown. It was known that genes were on chromosomes and chromosomes were composed of DNA and proteins, but it was believed that proteins are more varied in terms of chemical composition compared to DNA. What followed was a surprise.
* Output from the anonymity *
Between the two wars, the British researcher Frederick Griffith performed a series of experiments on bacteria, from which it emerged that the DNA was passed from one generation to another, DNA molecule having the capacity to transform the properties of the cell. A decade later, Oswald Avery and his colleagues at Rockefeller University from New York continued Griffith's experiment, trying to see what was with this molecule of heredity. Only in 1944 when they published the study, the world found out: on short, Avery and his group have shown that the transfer of DNA from a microbe to another also causes the transfer of characteristics. In the period that followed, other scholars, namely Phoebus Levene and Erwin Chargaff, conducted a series of studies that provided new information, including chemical components of DNA molecule.
* DNA fame *
In the absence of scientific basis brought from all these pioneers, Watson and Crick, those two researchers from Cambridge to whom is attributed the discovery, it wouldn't have arrived at the conclusion from 1953, when they described for the first time the DNA molecule as a three-dimensional helix (like a twisted ladder), it consists of two chains elastic organic connected by hydrogen bonds (the staircase).
They changed humanity forever and they were rewarded with the Nobel Prize for chemistry. DNA profile or genetic profile was developed several years later, in 1984 from English geneticist Alec Jeffreys from the University of Leicester.
Did you know...? If align DNA of all the cells of your body, you can make a round trip to the moon 6,000 times or you'll cross the distance to Pluto and back.The DNA is the mark of life, being present in all organisms from the tiny bacteria to giant whales. DNA is present in every cell of the body (except the red blood cells) and determines not only physical characteristics but also the diseases that are prone. Although we have access to information for more than 50 years, and with all the progress that science has made, DNA study is still in its infancy. „How much you know about the molecules that make you unique?”
* The unknown story *
It all started with Gregor Mendel, a Czech monk considered the father of genetics. The experiment he accomplished in 1857 on peas, that provided the information key about heredity, how it inherit traits from one plant to another (much later were called genes) and increased the interest in the study of genetics. But his work has remained in the shadows for nearly a century. Isn't was him to discover the DNA, it was the American biologist James Watson with English physicist Francis Crick, which in recent history is recording as the authors of giants performance. The molecule was isolated at the beginning of the second half of the nineteenth century from the Swiss chemist Friedrich Miescher. In 1869 the scientist concerned about white blood cells found a microscopic substance in the pus collected from surgical bandages, which he called nucleated. Later, he isolated a sample of what we now call DNA from salmon sperm, and in 1889, his student Richard Altmann called it nucleic acid. The substance in question exists only in chromosomes. In the first half of the twentieth century, the principles of genetic inheritance enunciated by Mendel a century ago finally were accepted, however, the chemical nature of heredity remained unknown. It was known that genes were on chromosomes and chromosomes were composed of DNA and proteins, but it was believed that proteins are more varied in terms of chemical composition compared to DNA. What followed was a surprise.
* Output from the anonymity *
Between the two wars, the British researcher Frederick Griffith performed a series of experiments on bacteria, from which it emerged that the DNA was passed from one generation to another, DNA molecule having the capacity to transform the properties of the cell. A decade later, Oswald Avery and his colleagues at Rockefeller University from New York continued Griffith's experiment, trying to see what was with this molecule of heredity. Only in 1944 when they published the study, the world found out: on short, Avery and his group have shown that the transfer of DNA from a microbe to another also causes the transfer of characteristics. In the period that followed, other scholars, namely Phoebus Levene and Erwin Chargaff, conducted a series of studies that provided new information, including chemical components of DNA molecule.
* DNA fame *
In the absence of scientific basis brought from all these pioneers, Watson and Crick, those two researchers from Cambridge to whom is attributed the discovery, it wouldn't have arrived at the conclusion from 1953, when they described for the first time the DNA molecule as a three-dimensional helix (like a twisted ladder), it consists of two chains elastic organic connected by hydrogen bonds (the staircase).
They changed humanity forever and they were rewarded with the Nobel Prize for chemistry. DNA profile or genetic profile was developed several years later, in 1984 from English geneticist Alec Jeffreys from the University of Leicester.
He devised a process by which an individual can be identified by its genetic heritage, a method consisting in extracting and analyzing the DNA from a cell derived from a human hair, leather, saliva, semen, and blood. Two people can have a similar genetic dowry, but some sequences of DNA structure they are specific to each individual, what makes us unique. Genetic analysis reveals precisely those sequences that create an unmistakable genetic profile. The method was first used, four years later, in 1988 in a murder case in Leicestershire (England). Thus began the history of DNA, with applications growing in the number of genetic fingerprinting:
- it is used to determine paternity, requiring only a sample of saliva or blood which is determined based on the barcode with half the features from the mother and half from the father, specific to each individual;
- it helps in identification of the genes responsible for hereditary diseases, to explain the mechanism by which some cells become cancerous and to establish predispositions to certain diseases. Diagnosis is faster, more precise and treatment - is personalized.
- forensic, genetic fingerprint facilitate discovery perpetrators of crimes even if they left only one footprint. Also, it helps in identifying victims disaster, unknown relatives etc., in finding the contaminations from water, air, soil, food.
* The human genome *
The whole sequence of DNA is called genome. It was obtained in 2003, in a large study named The human genome project, started in the nineties. The genome contains all the information that makes us what we are, is made up of nearly three billion bases of DNA (specialists are called chemical letters). Certain sequences of these letters create genes. It is estimated that there is about 30,000 DNA code of genes, few percents of the entire genome, the rest being made up of areas without information. The genetic material is the software that transmits to cellular machinery how to build proteins for the body to grow, survive and reproduce. Until the discovery of this system navigation, it took months or even years for researchers just to locate a single gene. Today, it can get in a few hours.
Thus, were identified genes that cause diabetes, leukemia and it's working on HIV and hepatitis C vaccine. A good news is more and more. Telomeres, DNA sequences, it shortens at each cell division and when they become too small, the cell dies. Researchers working on a formula that could prolong people's lives by extending the telomere life.
Video source - Youtube
Text source - magazine
