Electrical cables, garden hoses and strands of holiday lights seem to get themselves hopelessly tangled with no help at all. Research at the University of California, San Diego shows how knots form. Researchers say knot formation is important in many fields, including genetics. Knots often form in DNA, which is a long string-like molecule. Cells have enzymes that undo the knots by cutting the DNA strands so that they can pass through each other. Certain anti-cancer drugs stop tumor cells from dividing by blocking the unknotting of DNA.
Physicist Douglas Smith, an assistant professor of physics at the University of California-San Diego, speaks with Andrea Seabrook.