[math-fun] Junk DNA allegedly isn't. Big change in standard picture of life.
About 98% of the human genome was thought "junk." It was not genes (transcribed to make proteins). Humans have only about 25K genes. The junk often consisted of short repeating sequences. http://www.nytimes.com/2012/09/06/science/far-from-junk-dna-dark-matter-prov... NY Times today reporting on the gazillion dollar, gazillion author, ENCODE project claims the junk contains on the order of 4M "switches" which help regulate gene expression/not. It is analogous to a spaghetti-wiring circuit with 4M transistors, whose purpose is to control 25K real numbers. This greatly changes the whole "standard picture" of how life works. The old picture was few genes, each with some nearby regulatory elements, like islands in an ocean of useless junk DNA. The new picture is not as clear... but they claim about 50-80% of your DNA is "used" meaning "gets transcribed onto RNA" (but usually NOT transcribed further into protein) and the usage levels vary by a factor of 10^6. http://en.wikipedia.org/wiki/ENCODE http://www.ncbi.nlm.nih.gov/geo/info/ENCODE.html http://www.nature.com/nature/journal/v489/n7414/full/nature11233.html http://www.nature.com/nature/journal/v489/n7414/full/nature11247.html -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)
The Times article is pretty deceptive: anyone involved in actual biology has known that the non-coding regions of DNA that journalists have enjoyed calling "junk" actually has important functions. ENCODE really is a breakthrough, but it's in understanding details of how expression-switching mechanisms work. The deep conceptual shift to the realization that all the rest of our DNA was actually important happened two decades ago. (To be clear, I'm just bashing on the journalism here; the science is incredible.) --Michael On Wed, Sep 5, 2012 at 9:43 PM, Warren Smith <warren.wds@gmail.com> wrote:
About 98% of the human genome was thought "junk." It was not genes (transcribed to make proteins). Humans have only about 25K genes. The junk often consisted of short repeating sequences.
http://www.nytimes.com/2012/09/06/science/far-from-junk-dna-dark-matter-prov...
NY Times today reporting on the gazillion dollar, gazillion author, ENCODE project claims the junk contains on the order of 4M "switches" which help regulate gene expression/not. It is analogous to a spaghetti-wiring circuit with 4M transistors, whose purpose is to control 25K real numbers.
This greatly changes the whole "standard picture" of how life works. The old picture was few genes, each with some nearby regulatory elements, like islands in an ocean of useless junk DNA. The new picture is not as clear... but they claim about 50-80% of your DNA is "used" meaning "gets transcribed onto RNA" (but usually NOT transcribed further into protein) and the usage levels vary by a factor of 10^6.
http://en.wikipedia.org/wiki/ENCODE
http://www.ncbi.nlm.nih.gov/geo/info/ENCODE.html
http://www.nature.com/nature/journal/v489/n7414/full/nature11233.html
http://www.nature.com/nature/journal/v489/n7414/full/nature11247.html
-- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)
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Michael Kleber -
Warren Smith