Brian Cox, in his excellent first Wonders of Life programme extracted DNA fibres from his own saliva. What he didn’t explain was how the few cells extracted from his cheek by swilling out his mouth with saliva could produce thick curdy strands of DNA. In the cell the DNA is tightly supercoiled. When released it bursts out and uncoils. Every single cell contains up to 2m length of DNA. Each cell is only 1/100th mm in diameter so that’s a pretty amazing piece of packaging. If you try the experiment, you can pull out fine strands of DNA for quite a distance before they break. With practice and a steady hand you could probably pull a foot or two. A pity most of us don’t have the microscopes to see any further into this iconic substance.
RSS Feed
