DNA (deoxyribonucleic acid) is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus. DNA is made of chemical building blocks called nucleotides. These building blocks are made of three parts: a phosphate group, a sugar group and one of four types of nitrogen bases.Our types of nitrogen bases found in nucleotides are  adenine (A), thymine (T), guanine (G) and cytosine (C).

Genes

Genes, which are made up of DNA, act as instructions to make molecules called proteins. In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases. The Human Genome Project has estimated that humans have between 20,000 and 25,000 genes.

Chromosome

A chromosome is a single chain of DNA that is coiled and super coiled to form dense thread-like pieces. The term chromosome is derived from the Greek words “chroma” or color and “some” or body and is so named because chromosomes have the ability to be stained with dyes. Chromosomes occur in pairs, and there is a different number of pairs of chromosomes in different species of animals and plants. Humans have 23 pairs, elephants have 28 pairs, cats have 19 pairs and a carrot plant has 9 pairs of chromosomes. Chromosomes are not visible in the cell’s nucleus—not even under a microscope—when the cell is not dividing.
Each chromosome contains one DNA molecule. The DNA is coiled tightly around proteins called histones. These proteins provide structural support to a chromosome and allow the very long DNA molecule to form a compact shape and fit inside the nucleus of a cell.

Gene splicing

Gene splicing is a technique used in genetic engineering where the DNA of a living thing is edited, in some cases replacing existing genes with genes taken from another plant or animal.
It is a post-transcriptional modification in which a single gene can code for multiple proteins. This process by which genes are cut apart and put back together to provide them with some new function. Gene splicing enables a single gene to increase its coding capacity, allowing the synthesis of protein isoforms that are structurally and functionally distinct. Gene splicing is observed in high proportion of genes. In human cells, about 40-60% of the genes are known to exhibit alternative splicing.

DNA fingerprinting

DNA fingerprinting is a laboratory technique used to establish a link between biological evidence and a suspect in a criminal investigation.The process of DNA fingerprinting was first used during the 1980’s and its application was quickly to become that of identification of suspects involved in serious crimes including murder.
DNA fingerprinting was invented in 1984 by Professor Sir Alec Jeffreys after he realised you could detect variations in human DNA, in the form of these mini satellites.
fingerprinting help  Find out who a person’s parents or siblings are. This test also may be used to identify the parents of babies who were switched at birth.Solve crimes Blood, semen, skin, or other tissue left at the scene of a crime can be analyzed to help prove whether the suspect was or was not present at the crime scene. And Find out a body. This is useful if the body is badly decomposed or if only body parts are available, such as following a natural disaster or a battle.

Genetic engineering

Genetic manipulation, also called genetic engineering is the process by which scientists modify the genome of an organism.  It is the process of using technology to change the genetic makeup of an organism   be it an animal, plant or a bacterium. This Creation of genetically modified organisms requires recombinant DNA.
Genetic engineering also promises a revolution in agriculture. Recombinant DNA techniques enable scientists to produce plants that are resistant to herbicides and freezing temperatures, that will take longer to ripen, and that will manufacture a resistance to pests, among other characteristics.
Genetic engineering is performed by physically moving a gene from a donor organism into a recipient organism. It gives the organism the ability to express the trait encoded by the donated gene. Genetic manipulation involves finding an organism that naturally possesses a desired trait.

Scissors

Biological Scissors  or Genetic Scissors,  These enzymes were discovered in 1978 by two American scientists, Ham Smith, Daniel Nathans and a Swiss scientist, Werner Aber, for which they received the Nobel Prize in medicine.
The medical potential of gene editing - which acts like a pair of ‘genetic scissors’, allowing scientists to cut up DNA to disable genes or add new ones.
This type of enzyme has an ability to locate a certain part of a DNA sequence and cut it off like scissors.
Scientists are making tiny scissors called TALENs that can cut and fix a broken gene in a cell.  The technology isn’t ready for use in people yet but when it is, it could help us cure many different genetic diseases.  As long as those diseases are caused by problems with a single gene.