DNA restructured to see it at night

2009/07/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Genetika
• Zoologia

The eyes sticks of the night mammals have the DNA organized in a special way, which facilitates their nocturnal observation. To this conclusion some nuclear biologists from the Ludwig-Maximilians University of Munich have arrived, analyzing the retinas of 40 mammals.

Specifically, it has been found that the chromatine -- special structure of DNA for its organization in chromosomes with certain proteins -- is distributed differently in the sticks of the eyes and in the rest of the cells. Normally heterochromatine, part of DNA packaged without activity, is located on the edge of the nucleus and the eucromatine, less packaged and active, inside the nucleus. In the clubs of nocturnal mammals, heterochromatine penetrates the nucleus and the transcription of DNA occurs mainly on the edge of the nucleus.

Researchers have found that when heterochromatine is within the nucleus, the cells disperse much less light. Somehow these cells act as convergent lenses and focus light. Thanks to this, nocturnal animals make more of the few photons that arrive in the eyes.