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Celera's surprising and controversial success was due to several factors. First off, Celera was able to build upon the knowledge that previous sequencing efforts had gained through years of research and experience, including the Human Genome Project and The Institute for Genome Research (TIGR). Second, Celera's sequencing facilities were unparalleled in their sheer size. Celera's sequencing facilities had 50x the sequencing capacity of TIGR. Finally, because the results of the HGP were public, Celera was able to use their data to help align their shotgun sequences in the whole genome.

The human genome is 2.91-billion base pairs in length. Celera estimated that approx. 26,383 genes exist in the human genome, but this number has been a source of continued controversy with other estimates reaching as high as 150,000 genes (which is almost certainly much too high). Of the estimate 26,383 genes, 42% have an unknown function. The average number of exons in the predicted genes range between 4-5 and the typical exon length is around 100-300 base pairs. The average size of a human gene is around 27,000bp, with typical ranges between 20,000 and 50,000bp. A quick calculation will demonstrate that human genes are mostly intronic in composition. The average intron can be thousands of base pairs in size and can be as large as tens of thousands of base pairs (compare this to the typical exon with a paltry size of ~200bp). Coding regions in the human genome are estimated to account for only around 3% of the total DNA sequence, intronic sequences contribute ~30%, and intergenic regions ~67%.

The expansion of non-coding DNA in humans is particularly striking when compared to other metazoan eukaryotes. For example, the human genome is 30x larger than the C. elegans and the Drosophila genome, but has only ~2-3x as many genes. Furthermore, human genes are 10x larger than fly and worm genes, but the vast majority of this increase in size is due to intronic expansion; their exons are essentially the same size. Repeat sequences are another very prominent feature of the human genome. 35% of the entire human genome (including coding regions) is classified as repetitive, which is quite high already, but if we examine non-coding regions the proportion of repetitive DNA climbs to 46%. Compare these numbers to Arabidopsis which has a relatively low percentage of repeat sequences in the genome, 10%. But you should also keep in mind that Vivia faba, or the humble broadbean, is composed of upwards of 80% repetitive DNA.

Another important feature of the human (and other mammalian) genomes is CpG islands. A CpG island is a region of DNA that has a higher relative proportion of CpG dinucleotides when compared to the entire genome. This increased CpG density is significant because these regions tend to be unmethylated and therefore are believed to promote the initiation of transcription. This belief is drawn mainly from two observations: 1) most of the housekeeping genes (which are constitutively expressed genes) have CpG islands at the 5' end of the transcript, and 2) CpG island methylation is known to correlate with gene inactivation during gene imprinting and tissue specific gene expression.

Mus musculus

M. musculus

The mouse genome was sequenced by the Mouse Genome Sequencing Consortium in 2002 (Nature, Dec. 2002). Like the human genome, the mouse genome is large, 2.5Gb, only 14% smaller than the human genome. Gene prediction techniques estimate that there are 30,000 protein-coding genes in the genome. Approx. 99% of mouse genes have a direct, assignable human homologue. These genes are distributed among 19 autosomal chromosomes and one X chromosome. The mouse genome contains fewer CpG islands than the human genome (15,550 compared with 33,000) and, like the human genome, a large proportion of the mouse genome is composed of lowcomplexity repeat sequences. Sequencing the mouse genome was particularly important for a couple of reasons: the mouse is a ubiquitous as a research model, and for use as a comparative tool against the human genome.

Questions & Answers

how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
can nanotechnology change the direction of the face of the world
Prasenjit Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Genefinding. OpenStax CNX. Jun 17, 2003 Download for free at http://cnx.org/content/col10205/1.1
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