Genome

Genome Latest News

Researchers recently sequenced the first whole ancient Egyptian genome from an individual who lived 4,500 to 4,800 years ago — the oldest DNA sample from Egypt to date.

About Genome

• A genome is an organism’s complete set of genetic information. 
• A genome includes all of the hereditary instructions for creating and maintaining life, as well as instructions for reproduction. 
• The human genome, like all other cellular life forms, consists of DNA (deoxyribonucleic acid) and includes both the nuclear and mitochondrial DNA. This is in contrast to ribonucleic acid (RNA) viruses, whose genome is composed of RNA.
• 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.
  • 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.
• There are 23 pairs of chromosomes in the human genome. 
• Between 1990 and 2003, all twenty-three pairs were fully sequenced through an international research undertaking known as the Human Genome Project. 
• The study and analysis of genomes is called genomics.

‹ ›

Where is the Genome Found?

• In organisms known as eukaryotes (which includes humans, other mammals, plants and fungi), most of the genome is contained within a membrane-bound structure called the nucleus. 
• In humans and other complex multicellular organisms, a copy of the genome is found in nearly every cell in the body. 
• The exception to this is mammalian red blood cells, which do not contain a genome as they do not have a nucleus or mitochondria.
• Furthermore, human reproductive cells (eggs and sperm) each contain half the DNA from that person’s genome, which then combines to form a whole genome at fertilisation.
• Organisms known as Prokaryotes, which contain no inner membranes, store their genome in a region of the cytoplasm called the nucleoid. 

How long is a genome?

• The length of the genome varies between species and doesn’t necessarily reflect the size of the organism from which it came.
• The human genome is approximately 3 billion base pairs (3.2 to be exact) in length.
• While 3 billion is a big number, the rare Japanese flower called Paris japonica has a genome size of roughly 150 billion nucleotides, making it 50 times the size of the human genome.

Source: TH