In biology the genome of an organism is its whole hereditary information and is encoded in the DNA (or, for some viruses, RNA). Foundations of modern biology There are five unifying principles Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known Ribonucleic acid ( RNA) is a Nucleic acid that consists of a long chain of Nucleotide units This includes both the genes and the non-coding sequences of the DNA. History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance In Molecular biology, junk DNA is a provisional label for the portions of the DNA sequence of a Chromosome or a Genome for which no The term was adapted in 1920 by Hans Winkler, Professor of Botany at the University of Hamburg, Germany. Professor Hans Winkler ( 23 April 1877 - 22 November 1945) was a German Botanist. Botany, plant science(s, phytology, or plant biology is a branch of Biology and is the scientific study of plant Life The University of Hamburg (Universität Hamburg is a University in Hamburg, Germany. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. The Oxford English Dictionary suggests the name to be a portmanteau of the words gene and chromosome, however, many related -ome words already existed, such as biome and rhizome, forming a vocabulary into which genome fits systematically. A biome is a climatically and geographically defined area of ecologically similar climatic conditions such as communities of Plants Animals and In Botany, a rhizome is a horizontal stem of a Plant that is usually found underground often sending out Roots and Shoots ^[1]

More precisely, the genome of an organism is a complete genetic sequence on one set of chromosomes; for example, one of the two sets that a diploid individual carries in every somatic cell. A DNA sequence or genetic sequence is a succession of letters representing the Primary structure of a real or hypothetical DNA Molecule A chromosome is an organized structure of DNA and Protein that is found in cells. "Haplo" redirects here For the fictional character see The Death Gate Cycle. Somatic cells are any cells forming the body of an organism as opposed to Germline cells The term genome can be applied specifically to mean that stored on a complete set of nuclear DNA (i. In Cell biology, the nucleus (pl nuclei; from Latin la ''nucleus'' or la ''nuculeus'' "little nut" or kernel is a membrane-enclosed e. , the "nuclear genome") but can also be applied to that stored within organelles that contain their own DNA, as with the mitochondrial genome or the chloroplast genome. In Cell biology, an organelle (pronunciation /ɔː(rgəˡnɛl/ is a specialized subunit within a cell that has a specific function and is usually separately enclosed The mitochondrial genome is the genetic material of the Mitochondria. Chloroplasts are Organelles found in Plant cells and eukaryotic Algae that conduct Photosynthesis. When people say that the genome of a sexually reproducing species has been "sequenced," typically they are referring to a determination of the sequences of one set of autosomes and one of each type of sex chromosome, which together represent both of the possible sexes. The Evolution of sexual reproduction is a major puzzle The first Fossilized evidence of sexually reproducing Organisms is from Eukaryotes of the Stenian In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. For the sense of "sequencing" used in Electronic music, see the Music sequencer article An autosome is a non-sex Chromosome. It is an ordinarily paired type of chromosome that is the same in both Sexes of a species. A sex-determination system is a biological system that determines the development of sexual characteristics in an Organism. Even in species that exist in only one sex, what is described as "a genome sequence" may be a composite read from the chromosomes of various individuals. In general use, the phrase "genetic makeup" is sometimes used conversationally to mean the genome of a particular individual or organism. The study of the global properties of genomes of related organisms is usually referred to as genomics, which distinguishes it from genetics which generally studies the properties of single genes or groups of genes. Genomics is the study of an organism's entire Genome. The field includes intensive efforts to determine the entire DNA sequence of organisms and fine-scale Genetic Genetics (from Ancient Greek grc-Latn genetikos, “genitive” and that from grc-Latn genesis, “origin” a discipline of Biology, is History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance

Both the number of base pairs and the number of genes vary widely from one species to another, and there is little connection between the two. In Molecular biology, two Nucleotides on opposite complementary DNA or RNA strands that are connected via Hydrogen bonds are called At present, the highest known number of genes is around 60,000, for the protozoan causing trichomoniasis (see List of sequenced eukaryotic genomes), almost three times as many as in the human genome. Protozoa (in Greek πρῶτον proton "first" and ζῷα zoia "animals" are unicellular Eukaryotes (singular This list of sequenced eukaryotic genomes contains all the Eukaryotes The human genome is the Genome of Homo sapiens, which is stored on 23 chromosome pairs

An analogy to the human genome stored on DNA is that of instructions stored in a book:

• The book is over one billion words long;
• The book is bound 5000 volumes, each 300 pages long;
• The book fits into a cell nucleus the size of a pinpoint;
• A copy of the book (all 5000 volumes) is contained in almost every cell;

Contents 1 Types 2 Genomes and genetic variation 3 Genome projects 4 Comparison of different genome sizes 5 Genome evolution 6 See also 7 References 8 External links

Types

Most biological entities that are more complex than a virus sometimes or always carry additional genetic material besides that which resides in their chromosomes. A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable In some contexts, such as sequencing the genome of a pathogenic microbe, "genome" is meant to include information stored on this auxiliary material, which is carried in plasmids. A plasmid is an extra-chromosomal DNA molecule separate from the chromosomal DNA which is capable of replicating independently of the chromosomal DNA In such circumstances then, "genome" describes all of the genes and information on non-coding DNA that have the potential to be present.

In eukaryotes such as plants, protozoa and animals, however, "genome" carries the typical connotation of only information on chromosomal DNA. Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex So although these organisms contain mitochondria that have their own DNA, the genes in this mitochondrial DNA are not considered part of the genome. In Cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed Organelle found in most eukaryotic cells. In fact, mitochondria are sometimes said to have their own genome, often referred to as the "mitochondrial genome". The mitochondrial genome is the genetic material of the Mitochondria.

Genomes and genetic variation

Note that a genome does not capture the genetic diversity or the genetic polymorphism of a species. Polymorphism in biology occurs when two or more clearly different Phenotypes exist in the same population of a species — in other words the occurrence of more than one For example, the human genome sequence in principle could be determined from just half the information on the DNA of one cell from one individual. To learn what variations in genetic information underlie particular traits or diseases requires comparisons across individuals. This point explains the common usage of "genome" (which parallels a common usage of "gene") to refer not to the information in any particular DNA sequence, but to a whole family of sequences that share a biological context.

Although this concept may seem counter intuitive, it is the same concept that says there is no particular shape that is the shape of a cheetah. The cheetah ( Acinonyx jubatus) is an atypical member of the cat family ( Felidae) that is unique in its speed while lacking climbing abilities Cheetahs vary, and so do the sequences of their genomes. Yet both the individual animals and their sequences share commonalities, so one can learn something about cheetahs and "cheetah-ness" from a single example of either.

Genome projects

For more details on this topic, see Genome project. Genome projects are Scientific endeavours that ultimately aim to determine the complete Genome sequence of an Organism (be it an Animal, a

The Human Genome Project was organized to map and to sequence the human genome. The Human Genome Project (HGP was an international Scientific research project with a primary goal to determine the sequence of chemical base pairs which make up DNA For the sense of "sequencing" used in Electronic music, see the Music sequencer article Other genome projects include mouse, rice, the plant Arabidopsis thaliana, the puffer fish, bacteria like E. coli, etc. The House Mouse ( Mus musculus) is one of the most numerous species of the genus Mus commonly termed a Mouse. Rice is a Cereal foodstuff which forms an important part of the diet of many people worldwide and as such it is a staple food for many Arabidopsis thaliana ( A-ra-bi-dóp-sis tha-li-á-na; thale cress, mouse-ear cress or Arabidopsis) is a small Tetraodontidae is a family of primarily marine and estuarine fish In 1976, Walter Fiers at the University of Ghent (Belgium) was the first to establish the complete nucleotide sequence of a viral RNA-genome (bacteriophage MS2). Walter Fiers (b Ieper, Belgium, 1931 is a Belgian molecular biologist Ghent University (in Dutch Universiteit Gent, abbreviated UGent) is one of the three large Flemish universities. The Kingdom of Belgium is a Country in northwest Europe. It is a founding member of the European Union and hosts its headquarters as well as those This article is about a biological infectious particle for other uses see Phage (disambiguation. The first DNA-genome project to be completed was the Phage Φ-X174, with only 5368 base pairs, which was sequenced by Fred Sanger in 1977 . The phi X 174 (or phi X) Bacteriophage was the first DNA-based Genome to be sequenced by Fred Sanger and his team in 1977. Frederick Sanger, OM, CH, CBE, FRS (born 13 August 1918) is an English biochemist and twice The first bacterial genome to be completed was that of Haemophilus influenzae, completed by a team at The Institute for Genomic Research in 1995. Haemophilus influenzae, formerly called Pfeiffer's bacillus or Bacillus influenzae, is a non-motile Gram-negative Coccobacillus The Institute for Genomic Research ( TIGR) was a Non-profit Genomics research institute founded in 1992 by Craig Venter in

In May 2007, the New York Times announced that the full genome of DNA pioneer James D. Watson had been recorded. [1] The article noted that some scientists believe this to be the gateway to upcoming personalized genomic medicine.

Many genomes have been sequenced by various genome projects. The cost of sequencing continues to drop.

Comparison of different genome sizes

Main article: Genome size

Organism	Genome size (base pairs)	Note
Virus, Bacteriophage MS2	3,569	First sequenced RNA-genome[2]
Virus, SV40	5,224	[3]
Virus, Phage Φ-X174;	5,386	First sequenced DNA-genome[4]
Virus, Phage λ	50,000
Bacterium, Haemophilus influenzae	1,830,000	First genome of living organism, July 1995[5]
Bacterium, Carsonella ruddii	160,000	Smallest non-viral genome. Genome size refers to the total amount of DNA contained within one copy of a Genome. In Molecular biology, two Nucleotides on opposite complementary DNA or RNA strands that are connected via Hydrogen bonds are called A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable The bacteriophage MS2. MS2 phage is an icosahedral bacteriophage with a diameter of 27-34nm and an isoelectric point (pI of 3 A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable SV40 is an abbreviation for Simian vacuolating virus 40 or Simian virus 40, a Polyomavirus that is found in both Monkeys and A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable The phi X 174 (or phi X) Bacteriophage was the first DNA-based Genome to be sequenced by Fred Sanger and his team in 1977. A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable Enterobacteria phage λ ( Lambda phage) is a temperate bacteriophage that infects Escherichia coli The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Haemophilus influenzae, formerly called Pfeiffer's bacillus or Bacillus influenzae, is a non-motile Gram-negative Coccobacillus The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Candidatus Carsonella ruddii is an endosymbiotic Gamma Proteobacteria; it has the smallest Genome of any characterised bacteria [6]
Bacterium, Buchnera aphidicola	600,000
Bacterium, Wigglesworthia glossinidia	700,000
Bacterium, Escherichia coli	4,000,000	[7]
Amoeba, Amoeba dubia	670,000,000,000	Largest known genome. The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Buchnera aphidicola a member of the Proteobacteria, is the primary endosymbiont of Aphids (A The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Wigglesworthia glossinidia brevipalpis is a Gram-negative Bacterium in the family Enterobacteriaceae, related to E The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Amoeba (sometimes amœba or ameba, plural amoebae) is a Genus of Protozoa that moves The Amoeba dubia is the largest species of the kingdom Amoebozoa, more commonly referred to as Amoeba. [8]
Plant, Arabidopsis thaliana	157,000,000	First plant genome sequenced, Dec 2000. Plants are living Organisms belonging to the kingdom Plantae. Arabidopsis thaliana ( A-ra-bi-dóp-sis tha-li-á-na; thale cress, mouse-ear cress or Arabidopsis) is a small [9]
Plant, Genlisea margaretae	63,400,000	Smallest recorded flowering plant genome, 2006. Plants are living Organisms belonging to the kingdom Plantae. Genlisea margaretae is a carnivorous species in the Genus Genlisea (family Lentibulariaceae) native to areas of Madagascar The flowering plants or angiosperms ( Angiospermae or Magnoliophyta) are the most widespread group [9]
Plant, Fritillaria assyrica	130,000,000,000
Plant, Populus trichocarpa	480,000,000	First tree genome, Sept 2006
Yeast,Saccharomyces cerevisiae	20,000,000	[10]
Fungus, Aspergillus nidulans	30,000,000
Nematode, Caenorhabditis elegans	98,000,000	First multicellular animal genome, December 1998[11]
Insect, Drosophila melanogaster aka Fruit Fly	130,000,000	[12]
Insect, Bombyx mori aka Silk Moth	530,000,000
Insect, Apis mellifera aka Honey Bee	1,770,000,000
Fish, Tetraodon nigroviridis, type of Puffer fish	385,000,000	Smallest vertebrate genome known
Mammal, Homo sapiens	3,200,000,000
Fish, Protopterus aethiopicus aka Marbled lungfish	130,000,000,000	Largest vertebrate genome known

Note: The DNA from a single human cell has a length of ~1. Plants are living Organisms belonging to the kingdom Plantae. Plants are living Organisms belonging to the kingdom Plantae. Populus is a genus of between 25–35 species of Flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. Yeasts are a growth form of eukaryotic Microorganisms classified in the kingdom Fungi, with about 1500 Species currently described Saccharomyces cerevisiae is a Species of Budding Yeast. It is perhaps the most useful Yeast owing to its use since ancient times A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ Aspergillus nidulans (also called Emericella nidulans) is one of many species of filamentous Fungi in the phylum Ascomycota. The nematodes or roundworms ( Phylum Nematoda from Greek (nema "thread" + -ode "like" are one of the most common Caenorhabditis elegans (ˌsiːnoʊræbˈdaɪtɪs ˈɛlɪgænz is a free-living Nematode (roundworm about 1  mm in length which Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Drosophila melanogaster (from the Greek for black-bellied dew-lover) is a two-winged insect that belongs to the Diptera, the order Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two Tetraodon nigroviridis is one of the Pufferfish known as the Green spotted puffer (the other being Tetraodon fluviatilis) Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two The marbled lungfish, Protopterus aethiopicus, is a Lungfish of the family Protopteridae. The marbled lungfish, Protopterus aethiopicus, is a Lungfish of the family Protopteridae. 8 m (but at a width of ~2. 4 nanometers).

Since genomes and their organisms are very complex, one research strategy is to reduce the number of genes in a genome to the bare minimum and still have the organism in question survive. There is experimental work being done on minimal genomes for single cell organisms as well as minimal genomes for multicellular organisms (see Developmental biology). Developmental Biology is the official journal of the Society for Developmental Biology. The work is both in vivo and in silico. In vivo ( Latin: within the living means that which takes place inside an organism. In Silico is the second full-length studio album by Australian Drum and bass band Pendulum, released in Australia and

Genome evolution

Genomes are more than the sum of an organism's genes and have traits that may be measured and studied without reference to the details of any particular genes and their products. Measurement is the process of estimating the magnitude of some attribute of an object such as its length or weight relative to some standard ( unit of measurement) such as Researchers compare traits such as chromosome number (karyotype), genome size, gene order, codon usage bias, and GC-content to determine what mechanisms could have produced the great variety of genomes that exist today (for recent overviews, see Brown 2002; Saccone and Pesole 2003; Benfey and Protopapas 2004; Gibson and Muse 2004; Reese 2004; Gregory 2005). A karyotype is the characteristic Chromosome complement of a Eukaryote Species. Genome size refers to the total amount of DNA contained within one copy of a Genome. History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance Codon usage bias refers to differences among organisms in the frequency of occurrence of Codons in Protein -coding DNA sequences ( Genes. GC-content (or guanine-cytosine content in molecular biology is the percentage of Nitrogenous bases on a DNA molecule which are either Guanine or

Duplications play a major role in shaping the genome. Gene duplication (or chromosomal duplication) is any duplication of a region of DNA that contains a Gene; it may occur as an error in Homologous Duplications may range from extension of short tandem repeats, to duplication of a cluster of genes, and all the way to duplications of entire chromosomes or even entire genomes. A short tandem repeat (STR in DNA is a class of polymorphisms that occurs when a pattern of two or more Nucleotides are repeated and the repeated sequences Polyploidy occurs in cells and Organisms when there are more than two homologous sets of Chromosomes. Such duplications are probably fundamental to the creation of genetic novelty.

Horizontal gene transfer is invoked to explain how there is often extreme similarity between small portions of the genomes of two organisms that are otherwise very distantly related. Horizontal gene transfer seems to be common among many microbes. A microorganism (also spelled micro organism or micro-organism and also called a microbe) is an Organism that is Microscopic (usually Also, eukaryotic cells seem to have experienced a transfer of some genetic material from their chloroplast and mitochondrial genomes to their nuclear chromosomes. Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex Chloroplasts are Organelles found in Plant cells and eukaryotic Algae that conduct Photosynthesis. In Cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed Organelle found in most eukaryotic cells.

See also

References

External links

• Genomics Directory: A genomics and biotechnology database for scientists and students
• DNA Interactive: The History of DNA Science
• DNA From The Beginning
• All About The Human Genome Project from Genome.gov
• Animal genome size database
• Plant genome size database
• GOLD:Genomes OnLine Database
• The Genome News Network
• NCBI Entrez Genome Project database
• NCBI Genome Primer
• BBC News - Final genome 'chapter' published
• The Plant Genome
• IMG The Integrated Microbial Genomes system, for genome analysis by the DOE-JGI.
• CAMERA Cyberinfrastructure for Metagenomics, data repository and bioinformatics tools for metagenomic research
• GeneCards an integrated database of human genes.

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