What percent of the human genome is coding dna
Junk DNA: A Journey Through the Dark Matter of the Genome by Nessa CareyFrom the author of the acclaimed The Epigenetics Revolution (A book that would have had Darwin swooning - Guardian) comes another thrilling exploration of the cutting edge of human science. For decades after the structure of DNA was identified, scientists focused purely on genes, the regions of the genome that contain codes for the production of proteins. Other regions - 98% of the human genome - were dismissed as junk. But in recent years researchers have discovered that variations in this junk DNA underlie many previously intractable diseases, and they can now generate new approaches to tackling them. Nessa Carey explores, for the first time for a general audience, the incredible story behind a controversy that has generated unusually vituperative public exchanges between scientists. She shows how junk DNA plays an important role in areas as diverse as genetic diseases, viral infections, sex determination in mammals, human biological complexity, disease treatments, even evolution itself - and reveals how we are only now truly unlocking its secrets, more than half a century after Crick and Watson won their Nobel prize for the discovery of the structure of DNA in 1962.
What is noncoding DNA?
The human genome is the complete set of nucleic acid sequences for humans , encoded as DNA within the 23 chromosome pairs in cell nuclei and in a small DNA molecule found within individual mitochondria. These are usually treated separately as the nuclear genome, and the mitochondrial genome. Haploid human genomes, which are contained in germ cells the egg and sperm gamete cells created in the meiosis phase of sexual reproduction before fertilization creates a zygote consist of three billion DNA base pairs , while diploid genomes found in somatic cells have twice the DNA content. While there are significant differences among the genomes of human individuals on the order of 0. The first human genome sequences were published in nearly complete draft form in February by the Human Genome Project  and Celera Corporation.
Only about 1 percent of DNA is made up of protein-coding genes; the other 99 percent is noncoding. Noncoding DNA does not provide instructions for making proteins. However, it is becoming clear that at least some of it is integral to the function of cells, particularly the control of gene activity. For example, noncoding DNA contains sequences that act as regulatory elements, determining when and where genes are turned on and off. Such elements provide sites for specialized proteins called transcription factors to attach bind and either activate or repress the process by which the information from genes is turned into proteins transcription. Noncoding DNA contains many types of regulatory elements:.
Log in Advanced Search. The findings contradict the results of a similar study published in by a consortium of scientists from the ENCODE Encyclopedia of DNA Elements project, which claimed 80 percent of the human genome to be functional see BioNews We need only to sequence the sections we know are functional. Instead, the team conclude that only 10 - 15 percent or a maximum of 25 percent of the human genome is functional. The results were published in the journal Genome Biology and Evolution. By posting a comment you agree to abide by the BioNews terms and conditions.