A Double Image of the Double Helix

Remeasuring the double helix.

DNA is thought to behave as a stiff elastic rod with respect to the ubiquitous mechanical deformations inherent to its biology. To test this model at short DNA lengths, we measured the mean and variance of end-to-end length for a series of DNA double helices in solution, using small-angle x-ray scattering interference between gold nanocrystal labels. In the absence of applied tension, DNA is at...

Nanotechnology and the double helix.

Seeing beyond the double helix.

Epigenetics, or heritable changes not encoded in the DNA sequence, is a phenomenon important for an overall increase in the complexity of the genome without changes in gene sequence. Our complete genome is contained in each of our cells. Corneal cells are different than nerve cells due to a usage pattern of the genome that is maintained in a cellular memory of active or repressed genes. These “...

Double helix quantum computer

A new, “double helix” quantum computer architecture is proposed wherein the qubits are stored in two, dual physical worlds corresponding to the target versus the control qubit roles of controlled-not and other universal quantum gates.

50 years of the double helix.

IZINDABA An anniversary of major medical intere s t passed by virtually unnoticed last month. On 2 April 2003 it was exactly 50 years since the publication of a letter in the journal N a t u re by James Watson and Francis Crick 1. In it, they described the double helix molecular stru c t u re of deoxyribose nucleic acid (DNA) (Fig. 1), a publication which ushered in a new era in medicine. The t...