We are all made up of it. Me, you, that guy on the street corner, and even the tree in your backyard. Every living organism, and even some bacteria, contains a certain nucleic acid called DNA. Deoxyribonucleic acid, or DNA, is the basic building block for every single living organism on the planet. The main function of DNA is the long-term storage of information; it is essentially a tiny lock box that contains each and every one of our genetic information. Our DNA contains the blueprints to build and recreate components of cells such as RNA and proteins. The part of the DNA that contains the genetic information is called a gene.
Inside of the cells, the DNA is divided into units called chromosomes. In a process called DNA replication, the chromosomes are reproduced prior to the division of the cell. This division is crucial to the development of the new cells. The DNA is duplicated so that it will match with the DNA of the rest of the organism. DNA is a long polymer made up of smaller units called nucleotides, which are composed of sugars and ester bonds. Each sugar is attached to one of four types of molecules, commonly known as bases. The genetic code reads this information and specifies the series of amino acids embedded within the proteins.
The material we know today as DNA was discovered by a Swiss physician, Friedrich Miescher, in 1869 when he found a microscopic substance in the pus of a discarded surgical bandage. DNA, as many of us already know, is made in the shape of a double helix. Francis Crick and James Watson discovered the double helix structure in 1953, and it was published in journal that same year. The double helix is a right-handed spiral comprised of nucleic acids. Those nucleic acids are made up of nucleotides, which base pair together.
In 1959, French scientist Jrme Lejeune Down discovered that Down syndrome, a disease first discovered in 1866 by British doctor John Langdon Down, is a disease caused by the replication of the 21 chromosome, which leads to an over expression of certain genes located on the 21 chromosome. The maternal and paternal age affects whether or not a child is born with Down syndrome as well. At the maternal age of 20 to 24, the probability is 1/1562; between the ages 35 to 39 the probability is 1/214, and above the age 45 the probability is much higher with the probability in the neighborhood of 1/19.