What is a genome?

发布时间：2025-09-17 09:02

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Chromosome & Cell Nucleus with Telomere and Dna concept - 3d graphic

A genome is an organism’s complete set of genetic instructions. Each genome contains all of the information needed to build that organism and allow it to grow and develop.

Definition of a genome

Organisms are made up of millions of cells (100,000,000,000,000), each with their own complete set of instructions for building and sustaining that living thing. This set of instructions is known as our genome and is made up of DNA. Each cell in an organism, for example, a skin cell or a liver cell, contains this same set of instructions.

From genome to genes

The instructions in our genome are made up of DNA. Within DNA is a unique chemical code that guides an organism’s growth, development and health. This code is determined by the order of the four nucleotide bases that make up DNA, adenine, thymine, cytosine and guanine. DNA has a twisted structure in the shape of a double helix. Single strands of DNA are coiled up into structures called chromosomes. In animals, chromosomes are located in the nucleus within each cell. Within chromosomes, sections of DNA are organised into genes. Genes control different characteristics such as eye colour and height. All living things have a unique genome.

The human genome

The human genome is made of 3.2 billion bases of DNA but other organisms have different genome sizes. If printed out the 3.2 billion letters in your genome would: Fill a stack of paperback books 200 feet (61 m) high Fill 200 telephone directories, each with 500 pages. Take a century to recite, if we recited at one letter per second for 24 hours a day Extend 3,000 km (1,864 miles) - approximately the distance from London to the Canary Islands, Washington to Guatemala, or from New Delhi to Hanoi.