What Is a Genome

Modern biology and genetics refers to genome as the entire map of organism complete hereditary information. In some organisms, this information is enclosed in the DNA but for others like viruses, the information is contained in the RNA. The genome of an organism includes both its genes as well as the non-coding sequences of the DNA (components of the DNA that are not encoded for protein sequences). The term was first used in1920 by a professor of Botany, Hans Winkler at the University of Hamburg in Germany. The origin of the term can be traced to ancient Greek where it meant ‘I become’ or ‘to come into being’. However the Oxford dictionary traces the etiology of the word to a blend of two names; gene and chromosome.

Life as we know it is expressed in genomes. All organisms in the planet have genomes that hold all their biological information that is necessary to build up a living organism. The biological information that is contained in a genome code is prearranged in the deoxyribonucleic acid (DNA) as stated earlier, but it can also be encoded as RNA, and it is split up into discrete parts that we know as genes. This is what gives us the physical structure of genome. Below is the complete physical structure of the human genome.

Physical Structure of the Human Genome:

The first element of the human genome is the nuclear DNA. This is the core of every cell, a core that lies inside every cell providing a sanctuary of all genetic materials in humans. It is this nucleus that houses long strands of DNA.  There are four chemical bases constituents of the chain. These are:

  1. Adenine (A)
  2. Guanine (G)
  3. Cytosine (C)
  4. Thymine (T)

Each one of these chemical constituents has somewhat different levels of carbon, hydrogen, and nitrogen; the building blocks of organic life as we know it.  Each one of these bases is linked to a sugar molecule and a phosphate particle which form part of nucleic acid also known as nucleotide. Single nucleotides are attached together by the phosphate group and the precise order of linking is what determines the end product of that gene.

A gene is made from a twofold strand molecule that looks like a chain running parallel to each other. The chemical constituents of the double stranded DNA gives it a slightly twisting nature which has come to be referred to as a double helix. Chemical pairing connects the two strands of DNA together and this is where the human genome is found. There is a specific way that the various chemical bases bind to each other in a double helix, where Adenine binds to Thymine and Guanine binds to cytosine, giving an A-T and G-C pairs.