Strategic dominance

Genome size is the total amount of DNA contained within one copy of a single genome. It is typically measured in terms of mass in picograms (trillionths (10⁻¹²) of a gram, abbreviated pg) or less frequently in Daltons or as the total number of nucleotide base pairs typically in megabases (millions of base pairs, abbreviated Mb or Mbp). One picogram equals 978 megabases. In diploid organisms, genome size is used interchangeably with the term C-value. An organism's complexity is not directly proportional to its genome size; some single cell organisms have much more DNA than humans (see Junk DNA and C-value enigma).

Origin of the term

The term "genome size" is often erroneously attributed to Hinegardner, even in discussions dealing specifically with terminology in this area of research (e.g., Greilhuber, 2005). Notably, Hinegardner used the term only once: in the title. The term actually seems to have first appeared in 1968 when Hinegardner wondered, in the last paragraph of his article, whether "cellular DNA content does, in fact, reflect genome size". In this context, "genome size" was being used in the sense of genotype to mean the number of genes. In a paper submitted only two months later (in February 1969), Wolf et al. (1969) used the term "genome size" throughout and in its present usage; therefore these authors should probably be credited with originating the term in its modern sense. By the early 1970s, "genome size" was in common usage with its present definition, probably as a result of its inclusion in Susumu Ohno's influential book Evolution by Gene Duplication, published in 1970.

Variation in genome size and gene content

Genome sizes

The genome sizes of thousands of eukaryotes have been analyzed over the past 50 years, and these data are available in online databases for animals, plants, and fungi (see external links). Nuclear genome size is typically measured in eukaryotes using either densitometric measurements of Feulgen-stained nuclei (previously using specialized densitometers, now more commonly using computerized image analysis) or flow cytometry. In prokaryotes, pulsed field gel electrophoresis and complete genome sequencing are the predominant methods of genome size determination. Nuclear genome sizes are well known to vary enormously among eukaryotic species. In animals they range more than 3,300-fold, and in land plants they differ by a factor of about 1,000. Protist genomes have been reported to vary more than 300,000-fold in size, but the high end of this range (Amoeba) has been called into question.Template:By whom? In eukaryotes (but not prokaryotes), variation in genome size is not proportional to the number of genes, an observation that was deemed wholly counterintuitive before the discovery of non-coding DNA and which became known as the C-value paradox as a result. However, although there is no longer any paradoxical aspect to the discrepancy between genome size and gene number, this term remains in common usage. For reasons of conceptual clarification, the various puzzles that remain with regard to genome size variation instead have been suggested by one author to more accurately comprise a puzzle or an enigma (the C-value enigma). Genome size correlates with a range of features at the cell and organism levels, including cell size, cell division rate, and, depending on the taxon, body size, metabolic rate, developmental rate, organ complexity, geographical distribution, and/or extinction risk (for recent reviews, see Bennett and Leitch 2005; Gregory 2005). Based on completely sequenced genome data currently (as of April 2009) available, log-transformed gene number forms a linear correlation with log-transformed genome size in bacteria, archea, viruses, and organelles combined whereas a nonlinear (semi-natural log) correlation in eukaryotes (Hou and Lin 2009 ). The nonlinear correlation for eukaryotes, although claim of its existence contrasts the previous view that no correlation exists for this group of organisms, reflects disproportionately fast increasing noncoding DNA in increasingly large eukaryotic genomes. Although sequenced genome data are practically biased toward small genomes, which may compromise the accuracy of the empirically derived correlation, and the ultimate proof of the correlation remains to be obtained by sequencing some of the largest eukaryotic genomes, current data do not seem to rule out a correlation.

Genome reduction

Genome reduction, also known as Genome degradation, is the process by which a genome shrinks relative to its ancestor. Genomes fluctuate in size regularly, however, genome size reduction is most significant in bacteria.

The most evolutionary significant cases of genome reduction may be the eukaryotic organelles that are derived from bacteria: the mitochondrion and plastid. These organelles are descended from endosymbionts, which can only survive within the host cell and which the host cell likewise needs for survival. Many mitochondria have less than 20 genes in their entire genome, whereas a free-living bacterium generally has at least 1000 genes. Many genes have been transferred to the host nucleus, while others have simply been lost and their function replaced by host processes.

Other bacteria have become endosymbionts or obligate intracellular pathogens and experienced extensive genome reduction as a result. This process seems to be dominated by genetic drift resulting from small population size, low recombination rates, and high mutation rates, as opposed to selection for smaller genomes.

Some free-living marine bacterioplanktons also shows signs of genome reduction, which are hypothesized to be driven by natural selection.

Genome reduction in obligate endosymbiotic species

Obligate endosymbiotic species are characterized by a complete inability to survive external to their host environment. These species have become a considerable threat to human health, as they are often highly capable of evading human immune systems and manipulating the host environment to acquire nutrients. A common explanation for these keen manipulative abilities is the compact and efficient genomic structure consistently found in obligate endosymbionts. This compact genome structure is the result of massive losses of extraneous DNA - an occurrence that is exclusively associated with the loss of a free-living stage. In fact, as much as 90% of the genetic material can be lost when a species makes the evolutionary transition from a free-living to obligate intracellular lifestyle. Common examples of species with reduced genomes include: Buchnera aphidicola, Rickettsia prowazekii and Mycobacterium leprae. One obligate endosymbiont of psyllid, Candidatus Carsonella ruddii, has the smallest genome currently known among cellular organisms at 160kb. It is important to note, however, that some obligate intracellular species have positive fitness effects on their hosts. (See also mutualists and parasites.)

The reductive evolution model has been proposed as an effort to define the genomic commonalities seen in all obligate endosymbionts. This model illustrates four general features of reduced genomes and obligate intracellular species:

1. ‘genome streamlining’ resulting from relaxed selection on genes that are superfluous in the intracellular environment;
2. a bias towards deletions (rather than insertions), which heavily affects genes that have been disrupted by accumulation of mutations (pseudogenes);
3. very little or no capability for acquiring new DNA; and
4. considerable reduction of effective population size in endosymbiotic populations, particularly in species that rely on vertical transmission.

Based on this model, it is clear that endosymbionts face different adaptive challenges than free-living species.

Conversion from picograms (pg) to base pairs (bp)

Mining Engineer (Excluding Oil ) Truman from Alma, loves to spend time knotting, largest property developers in singapore developers in singapore and stamp collecting. Recently had a family visit to Urnes Stave Church.

${\text{number of base pairs}}={\text{mass in pg}}\times 0.978\times 10^{9}$

or simply:

$1{\text{pg}}=978{\text{Mb}}$

Drake's rule

In 1991 Drake proposed a rule: that the mutation rate within a genome and its size were inversely correlated. This rule has been found to be approximately correct for DNA viruses and unicellular organisms. Its basis is unknown.

The small size of RNA viruses has been proposed to be locked into a three part relation between replication fidelity, genome size and genetic complexity. The majority of RNA viruses lack an RNA proofreading facility which limits their replication fidelity and hence the genome size. This has also been described as the Eigen paradox.

An exception to the rule of small genome sizes in RNA viruses is found the Nidoviruses. These viruses appear to have acquired a 3′-to-5′ exoribonuclease (ExoN) which has allowed for an increase in genome size.

See also

Organisational Psychologist Alfonzo Lester from Timmins, enjoys pinochle, property developers in new launch singapore property and textiles. Gets motivation through travel and just spent 7 days at Alejandro de Humboldt National Park.

• Comparison of different genome sizes
• Animal Genome Size Database
• Cell nucleus
• Comparative genomics
• C-value
• C-value enigma
• Genome
• Human genome
• Junk DNA
• List of sequenced eukaryotic genomes
• Noncoding DNA
• Plant DNA C-values Database
• Selfish DNA
• Transposable elements
• Bacterial Genome Size

42 year-old Environmental Consultant Merle Eure from Hudson, really loves snowboarding, property developers in new launch ec singapore and cosplay. Maintains a trip blog and has lots to write about after visiting Chhatrapati Shivaji Terminus (formerly Victoria Terminus).

References

43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro.

Further reading

• Evolution of Chlamydiaceae
• One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
  
  In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
  
  Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
  
  Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
  
  A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
  
  The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
  
  There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang

External links

• Animal Genome Size Database
• Plant DNA C-values Database
• Fungal Genome Size Database
• Fungal Database — by CBS