Difference Between Gene and Genome

The species present in the world are diverse and each one has a unique set of hereditary characteristics that make them different from the others. These characteristics are encoded in DNA molecules, present in cells. Difference Between Gene and Genome

Genes and the genome are associated with DNA and are defined by the same molecules. DNA is the basic unit of inheritance that is found mainly in the chromosomes present in the nucleus of the cells of almost all organisms that we know of. But it is important that you know that gene and genome are not the same, which is why below we explain what the difference consists of.

GEN Difference Between Gene and Genome

A gene is a molecular unit of heredity in a living organism. Living things depend on genes and functional chains of RNA and proteins.

Genes contain the information to build and maintain the cells of an organism and to pass genetic traits to offspring. This does mean that they are elements that determine the inherited characteristics that are transmitted from parents to their offspring in reproduction.

They are associated with DNA molecules , which is the main genetic material found in all living organisms. Genes are made up of specific segments or portions of DNA. These specific segments are able to control the specific characteristics of inheritance. This is generally done by DNA transcription and DNA translation processes.

During reproduction, the offspring obtain genes from both parents. These different forms of genes are called alleles. A single allele or multiple alleles are responsible for controlling certain characteristics and functions of an organism.


In molecular biology and genetics , the genome is the totality of the hereditary information of an organism. It is encoded in DNA molecules. The total content of DNA in a single cell is known as the organism’s ‘genome’, but some organisms have only RNA so their genome is the total amount of RNA content.

From the above it follows that the genome includes both DNA and RNA. For this reason, the genome is even part of non-chromosomal genetic elements such as viruses, plasmids. The total content of DNA in the nucleus of a cell is called the ‘nuclear genome’ and the total content of DNA in the mitochondria is called the ‘mitochondrial genome ‘. 

The study of the genome and the characteristics related to organisms is called Genomics. The evolution of genomes can be studied and identified by their composition, which includes size, proportion, repetitive and non-repetitive DNA.

If we consider the human genome, it contains 23 chromosomes and of these only one chromosome determines sex, while the remaining 22 are autosomal chromosomes. There are approximately 20,000 to 25,000 genes in the human genome. Since 1990, the Human Genome Project was carried out, which sought to identify and determine the chemical bases of DNA.

Key differences between gene and genome

  • Genes are units of inheritance made up of DNA and occupying a fixed position on chromosomes, while the genome surrounds the set of genes contained in a chromosome.
  • Genes are segments of DNA, while the genome is the total content of these in the cell.
  • Genetics deals with the study of genes, while Genomics deals with the study of the genome.
  • An organism has billions of genes, but only one genome.

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