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If the human genome were put in a straight line, it would be over six and a half feet long. So how do you store all that DNA in a tiny nucleus? And have the cell manage it? Researchers explain how in a study featured on the cover of the October 9th issue of the journal Science.
Using new analytic techniques, Erez Lieberman and colleagues found that the genome is packed into what’s called a “fractal globule”—despite being intensely twisted, the string of genes never knots. This type of shape was mathematically postulated over a century ago, and has now been shown to describe the genome’s three-dimensional structure.
But the big finding is that the cell nucleus has two compartments—and genes are only active in one. All cells carry the same complete genome, but different genes get turned on, for example, in a liver cell compared with a nerve cell. Turns out that the genes to be used in a given cell get shuttled into the nucleus’s active section. Dormant genes stay out. The system allows each cell to make sense of information stored trillions of times more densely than what’s on a computer chip.
—Cynthia Graber
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6 Comments
Add Comment"Fractal globule"? I think that's the first time I've ever heard that. After reading through a lot of material to find out how genes become activated while others remain dormant, it seems this extra dimension is finally going to help put it all into perspective. At least, it will make it much easier for some of us to understand. How do the genes get "shuttled into the nucleus's active section"? I look forward to a more in depth article from SCIAM.
Reply | Report Abuse | Link to thisI want to know the name of the song!!
Reply | Report Abuse | Link to thissounds great ~
I am also looking forward to
Reply | Report Abuse | Link to thisYeah, when I first heard about this news, I was shocked and excited.It seems that this structure of chromosome will help scientist to solve the problem in chromosome integration and degradation. And I am interested in this area and want to do some deep research after I entered graduate school!I will keep noticing about this topic!
Reply | Report Abuse | Link to thisAs a non-biologist I'm confused. What's the relationship between this genome globule, which the article seems to describe as a single long strand of DNA, and the 23 pairs of chromosomes that other sources portray (even with photographs) as the physical arrangement of the human genome? Is the genome normally a globule, arranged into chromosomes only during mitosis?
Reply | Report Abuse | Link to this"The system allows each cell to make sense of information stored trillions of times more densely than what’s on a computer chip."
Reply | Report Abuse | Link to thisThat's saying a lot, but not enough. I get the fractal packing thing, but "trillions of times more densely than what’s on a computer chip": that is a monumental concept that calls for further explanation.