DNA molecule

DNA - The substance of inheritance is the most celebrated molecule of our time DNA, with its double-stranded spiral, is among the most elegant of all biological molecules. But the double helix is not just a beautiful structure, it also gives DNA incredible stability and permanence, providing geneticists with a unique window to the past.

DNA molecule

The idea that organisms pass on information has been with us for centuries – any look at three generations of humans (grandfather, father, and son, say) will usually demonstrate that, somehow, physical features are hereditary. The theory of evolution also assumes that a given generation of a species is a continuation, and perhaps adaptation, from its preceding generations and yet, for a long time, there weren't any good explanations of how species inherit traits.

DNA was isolated in 1869, and over the next 50 years scientists gradually refined their understanding of the molecule. Around 1930, scientists began to hypothesize that DNA was a carrier of hereditary information. In 1943, Oswald Avery confirmed that hypothesis.

The remaining mystery was the molecule 's precise structure. In 1953, James Watson and Francis Crick were able to identify the double helix structure; 10 years later, they were awarded the Nobel Prize for their discovery.

Thus was born the field of molecular biology. In 1951–53 the British molecular biologist F.H.C. Crick and the United States biochemist James D.Watson, in association with the British physicist Maurice H.F. Wilkins, analyzed photographic images produced by X rays directed through DNA molecules.

Greatest discovery ever Years ago, Francis Crick and James Watson heralded a revolution in the world of genetics by discovering the structure of DNA molecule in 1953.

Elegant double–helical model

James Watson and Francis Crick shook the scientific world with an elegant double–helical model for the structure of deoxyribonucleic acid, or DNA. They determined that the DNA in cells is usually in the form of a double stranded helix (the shape of two stretched, intertwined coiled springs), one DNA molecule being wrapped around another. RNA, on the other hand, is usually a single strand.

Over the past 50 years, their model has evolved from a novel proposition to an icon of modern biology. DNA, the substance of inheritance, is the most celebrated molecule of our time. Mendel 's heritable factors and Morgan 's genes on chromosomes are, in fact, composed of DNA.

Chemically speaking, your genetic endowment is the DNA contained in 46 chromosomes, you inherited from your parents. In fact, it 's hard to think of another molecule that performs so many intelligent functions so effortlessly.

Significant DNA Molecule Our genetic endowment is DNA contained in 46 chromosomes, we inherited from our parents.

DNA in growth All known living organisms use genetic information in their cell growth and development, division, and function – and DNA is responsible for encoding that information

Importance of DNA

DNA (deoxyribonucleic acid) is an extremely important molecule for life on Earth. All known living organisms use genetic information in their cell growth and development, division, and function – and DNA is responsible for encoding that information.

The DNA is unique in its ability to direct its own replication and the resemblance of offspring to their parents has its basis in the precise replication of DNA and its transmission from one generation to the next.

Hereditary information is encoded in the chemical language of DNA and reproduced in all the cells of your body. It is this DNA program that directs the development of your biochemical, anatomical, physiological and to some extent, behavioral traits.

Basis of inheritance

To geneticists, the arrangement of bases in a DNA molecule spells out a "language" known as the genetic code. A sequence of three specific bases forms the code for one amino acid in a protein.

Since DNA contains four different bases, each of which occurs thousands of times in human cells, the number of possible different arrangements of these bases is astronomically high. This makes possible the wide diversity that exists in the genetic makeup of human beings. At conception, the characteristics of the offspring are determined by the arrangement of bases in the DNA of the parents.

So what is it that makes DNA so smart?

Hereditary information is encoded in the chemical language of DNA and reproduced in all the cells of our body. It is this DNA program that directs the development of our biochemical, anatomical, physiological and to some extent, behavioral traits. DNA may be tiny but with properties including stability, flexibility, replication and the ability to store vast amounts of data, there's a reason why it must be one of the smartest known molecules ever known.

Double helical model of DNA DNA is usually a double-helix and has two strands running in opposite directions.

Structure and Composition of DNA

Structurally, DNA is a double helix (much like a spiral staircase), and each step in the chain is part of a long code that conveys genetic information. The backbone, according to the Watson Crick model, forms the coil of the helix, and the bases jut inward toward the axis of the helix. The double helix is anti – parallel, meaning each strand runs in a different direction.

Resembling a twisted ladder or a zipper, DNA is formed with nucleotides (structural units of DNA containing a base, a sugar, and one or more phosphates), a phosphate and sugar backbone, and nitrogenous bases. There are four bases, and each one will only bond with its complement.

Adenine will only bond with Thymine, and Cytosine with only Guanine. The bases on the two backbones are joined to one another in pairs by relatively weak chemical bonds called hydrogen bonds. The hydrogen bonds linking the bases in DNA are easily broken, so that the two strands can be partially or completely separated. The adenine on one backbone is always paired with thymine on the other, and guanine is always paired with cytosine. The bonding theories are extensively explained in Chemistry with Lewis dot structures.

DNA is the smartest known molecules ever known It's hard to think of another molecule that performs so many intelligent functions so effortlessly.

DNA acts as smart facsimile machine

Our cells need to divide, so we can grow and re–build, but every cell needs to have the instructions to know 'how to be' a cell. DNA provides those instructions – so a new copy of itself must be made before a cell divides. It's the super–smart structure that makes this easy. The 'rungs' of the DNA ladder are made from one of four nitrogen–based molecules, commonly known as A, T, G and C. These form complementary pairs – A always joins with T and G always joins with C.

So, one side of the double–stranded DNA helix can be used as a template to produce a new side that perfectly complements it. A bit like making a new coat zip, but by using half of the old zip as a template. The original side and the new one combine together to form a new DNA double helix, which is identical to the original.

Cleverly, human DNA can unzip and 'replicate' at hundreds of places along the structure at the same time – speeding up the process for a very long molecule.

Structurally, DNA is a double helix, much like a spiral staircase. DNA is very tightly folded, it is compacted in a way that allows it to easily become available to the many enzymes in the cell that replicate it, repair it, and use its genes to produce proteins.

Super coiling of DNA

Each of us has enough DNA to reach from here to the sun and back, more than 300 times. How is all of that DNA packaged so tightly into chromosomes and squeezed into a tiny nucleus? The answer to this question lies in the fact that certain proteins compact chromosomal DNA into the microscopic space of the eukaryotic nucleus. These proteins are called histones, and the resulting DNA–protein complex is called chromatin. It may seem paradoxical that proteins are added to DNA to make it more compact.

However, if you have ever tried to store a garden hose, you know that it is much easier to do so if you begin by coiling the hose. It coils – much like a telephone cord – into tight complex structures called chromatin without corrupting the vital information within.

As coiling requires work, and energy is needed to perform work, histones within the nucleus, provide the energy (mainly in the form of electrostatic interactions) to fold DNA. As a result, chromatin can be packaged into a much smaller volume than DNA alone.

DNA: Database of the New Age The information storage density of DNA is at least a thousand times greater than that of existing media.

DNA – The ultimate hard drive

Genes are made up of stretches of the DNA molecule which contain information about how to build proteins – the building blocks of life which make up everything about us.

Different sequences of the four types of DNA bases make 'codes' which can be translated into the components of proteins, called amino acids. These amino acids, in different combinations can produce at least 20,000 different proteins in the human body. Even the world's most powerful hard drives cannot compete with the storage power of DNA.

"There is enough information in one DNA molecule to fill 1,000 books. All of a person's features are encoded in an alphabet, symbolized in the letters A, T, G and C".

GM Children Today, our understanding of DNA enables us to do unimaginable things‐ Genetically altered children resulting from US – DNA research and experiments.

Personal DNA SequencingIn the future, personal DNA sequencing will become even more affordable and easy to check for any genetic abnormalities.

Milestones in DNA and RNA research

DNA is the substance in booming field of genomic research. The discovery of ribozymes (an RNA molecule capable of acting as an enzyme) has profoundly altered our view of how life might have evolved. We can now imagine that there was a primitive form of life based entirely on RNA.

In this world, RNA would have functioned as the genetic material and as the enzymatic machines. This RNA world would have preceded life as we know it today, in which information transfer is based on DNA, RNA, and protein. Research has also shown that the instructions stored within DNA are "read" in two steps: transcription and translation.

Today, our understanding of DNA enables us to do previously unimaginable things. We can genetically modify organisms by manipulating their DNA – a controversial ability that was anticipated very early on. We can use DNA samples left behind at crime scenes to identify criminals. Another recent development, the Human Genome Project, attempted to sequence all the DNA in the human cell. The project was completed in 2003.

Today, a vast database of sequenced genomes exists (from animals, bacteria, fungi, and more) and allows scientists to quickly compare various species, extract important information (such as genetic relatedness), and learn about mutations and diseases. We can also pay to have your own DNA sequenced, which can give you some idea of the diseases you are genetically predisposed to, inform you about your genetic and ancestral history, and more.

Personal DNA sequencing in future!

In the future, personal DNA sequencing will become even more affordable and easy, though whether it becomes widespread remains to be seen.

Recombinant DNA (sometimes called synthetic biology) refers to the manipulation or creation of DNA sequences. It first came into practice in the 1970s and is a rapidly expanding field. Recombinant DNA has immense potential and could be used to treat genetic diseases and deficiencies.

DNA Forensics DNA is very much useful in identifying potential suspects whose DNA may match evidence left at crime scenes.

Applications

Forensics & DNA fingerprinting

DNA Forensics (Identification)

DNA is very much useful in identifying potential suspects whose DNA may match evidence left at crime scenes. This helps in helping those who were wrongly accused in crimes.
Establish paternity and other family relationships.
Identify endangered and protected species as an aid to wildlife officials (could be used for prosecuting poachers).
Detect bacteria and other organisms that may pollute air, water, soil, and food.
Match organ donors with recipients in transplant programs.
Determine pedigree for seed or livestock breeds.
Authenticate consumables such as caviar and wine.

Applications of Bioinformatics in medicine Bioinformatics tools aid in the comparison of genetic and genomic data and more generally in the understanding of evolutionary aspects of molecular biology.

Benefits of BiotechnologyBiotechnology solve the problems of poverty, inadequate nutrition and even environmental degradation across the world.

Biomedical informatics

Is a combination of information technology processes with medicine. Bioinformatics basically means a detailed study of a subject using host of tools and techniques from applied mathematics, statistics, computer science, artificial intelligence etc.

So when we say biomedical informatics we are studying medical applications, medicine and health in particular. That is applying bioinformatics for improving health and studying health in detail. Bioinformatics is applied in gene finding, genome assembly, prediction of gene expression and protein‐protein interactions, and the modeling of evolution.

Biotechnology: Biotechnology is the science of working with living cells and their molecules to produce varied products for the benefit of mankind. Biotechnology thus can also be defined as the manipulation of organisms to do practical things and to provide useful products.

Biotechnology has been used since centuries; however recent developments have made the filed exciting. During the earlier eras, biotechnology was used to bake bread, brew alcoholic beverages, and breed food crops or domestic animals. The discovery that DNA stores genetic information was an important breakthrough that led to rapid development of Biotechnology.

DNA and computation: DNA is also being used for computing or rather computer processors. DNA computing is advantageous over electronic computers in power use, space use, and efficiency, due to its ability to compute in a highly parallel fashion ,efficiency, due to its ability to compute in a highly parallel fashion. Israeli scientists have built a computer using DNA . A trillion DNA processors fit in a test tube and can perform a billion operations a second with 99.8 percent accuracy. The data are store in living organisms and offer a glimpse into the future of nanoscale computing. This is the first autonomous computer made of bimolecular software and hardware.

DNA plays a major role in evolutionary change By examining DNA sequences in different populations, scientists can determine the closeness of relationships between populations (or within populations).

Anthropology

DNA collects mutations over time, which is then inherited, it contains historical information and by comparing DNA sequences, geneticists can infer the evolutionary history of organisms, If DNA sequences within a species are compared, population geneticists can learn the history of particular populations. This can be used in studies ranging from ecological genetics to anthropology (for example, DNA evidence is also being used to try to identify the Ten Lost Tribes of Israel.

References and Further Study

http://www.saasta.ac.za/biosciences/dna.html
http://en.wikipedia.org/wiki/DNA
http://learn.genetics.utah.edu/
http://itrain.org/itinfo/2001/it011122.html

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