genome

the ordering of genes in a haploid set of chromosomes of a particular organism

the full DNA sequence of an organism

"the human genome contains approximately three billion chemical base pairs"

otheruses In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). This includes both the genegenes and the Junk DNAnon-coding sequences. The term was first coined, in 1920, by Hans Winkler, Professor of Botany at the University of Hamburg. unsolvedbiologyOther than the structural genes, which is the simpler part of the system? What is the complete structure and function of the proteome proteins expressed by a cell or organ at a particular time and under specific conditions? What is the complete function of the regulator genes? More precisely, the genome of an organism is a complete DNA sequence of one set of chromosomes; for example, one of the two sets that a diploid individual carries in every somatic cell. The term genome can be applied specifically to mean the complete set of ''cell nucleusnuclear DNA'' (i.e., the nuclear genome) but can also be applied to organelles that contain their own DNA, as with the mitochondriamitochondrial genome or the chloroplast genome. When people say that the genome of a sexual reproductionsexually reproducing species has been "sequencingsequenced," 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. Even in species that exist in only one sex, what is described as "a genome sequence" may be a composite 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.

Types of genomes - Most biological entities more complex than a virus (biology)virus sometimes or always carry additional genetic material besides that which resides in their chromosomes. In some contexts, such as sequencing the genome of a pathogenic microbe, "genome" is meant to include this auxiliary material, which is carried in plasmids. In such circumstances then, "genome" describes all of the genes and non-coding DNA that have the potential to be present. In vertebrates such as humans, however, "genome" carries the typical connotation of only chromosomal DNA. So although human mitochondria contain genes, these genes are not considered part of the genome. In fact, mitochondria are sometimes said to have their own genome, often referred to as the "mitochondrial genome".

Genomes and genetic variation - Note that a genome does not capture the genetic diversity or the genetic polymorphism (biology)polymorphism of a species. For example, the human genome sequence in principle could be determined from just half the DNA of one cell from one individual. To learn what variations in DNA 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 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. 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.

Minimal genomes - 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). The work is both ''in vivo'' and ''in silico''. By understanding the functioning of minimal organisms one hopes to add complexity incrementally leading to the understanding of multicellular diseases such as Cancer.(see #References)

Genome projects - ''Main article Genome projectThe Human Genome Project was organized to physical mapmap and to sequencingsequence the human genome. Other genome projects include mus musculusmouse, rice, the plant Arabidopsis thaliana, the puffer fish, bacteria like E. coli, etc. Many genomes have been sequenced by various genome projects. The cost of sequencing continues to drop, and it is possible that eventually an individual's genome could be sequenced for around several thousand dollars (US).''Compare proteome

Comparison of different genome sizegenome sizes - < ;th>Organism< th>Genome? size (base !pairs)&l t;tr>&l t;tr>Plant,? ''Fritillary Fritillary assyriaca !assyrica''10? - Largest known !genome&l t;tr>7& lt;tr>< tr>2×10^{8< ;/sup>}< /table>''Note? The DNA from a single human cell has a length of ~1.8m.

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. Researchers compare traits such as karyotypechromosome number, 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). gene duplicationDuplications play a major role in shaping the genome. 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 polyploidyentire genomes. 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. Also, eukaryotic cells seem to have experienced a transfer of some genetic material from their chloroplast and mitochondrial genomes to their nuclear chromosomes.

Other Omics & Ome pages -

Genome, Proteome, Expressome, Metabolome, Regulome, Functome, Phenome, Textome

Mitochondriomics, Golgiome, Ligandomics, Eukaryome, Bacteriome, Archaeome

Subfields of Genome -

Human genome, Mitochondriome, Eukaryome

References - Benfey, P and Protopapas, AD (2004). Essentials of Genomics. Prentice Hall.Brown, TA (2002). Genomes 2. Bios Scientific Publishers.Gibson, G and Muse, SV (2004). A Primer of Genome Science (Second Edition). Sinauer Assoc.Gregory, TR (ed) (2005). The Evolution of the Genome. Elsevier.Reece, RJ (2004). Analysis of Genes and Genomes. John Wiley & Sons.Saccone, C and Pesole, G (2003). Handbook of Comparative Genomics. John Wiley & Sons.

See also -

Developmental biology, evolution, molecular systematics, molecular evolution, gene family, gene

External links -

genomesize.com - Animal genome size database

rbgkew.org.uk - Plant genome size database

genomesonline.org - Genomes OnLine Database

genomenewsnetwork.org - The Genome News !NetworkCategory:Geneticsca:Gen omacs:Genomda:Arvemassede:Geno met:Genoomes:Genomafr:Génomek o:게놈ia:Genomait:Genomahe:� �נוםnl:Genoomja:ゲノムpl :Genompt:Genomaru:Геномsv :Genom

Virus,? Phi-X174 phagePhage !Φ-X174;
Virus,? lambda phagePhage !λ	5 ×104
Bacterium,? ''Escherichia !coli''	4&t imes;106
Fungus,''Sac charomyces? !cerevisiae''
Nematoda Nematode, ''Caenorhabditis !elegans''	8×107
Insect,? ''Drosophila !melanogaster''	Mammal,? ''Homo !sapiens''	3×109