By injecting multiply-labeled DNA into tissue culture cells, Dr. Paddock was able to produce this beautiful image using a confocal laser scanning microscope. The various fluorescent colors each represent different target genes for the probes utilized in the experiment.

Fluorescent DNA Specimen: Fluorescent DNA in Tissue Culture Cells Technique: Fluorescence (Multiple Probes)

DNA is a very unusual molecule that is shaped like a very long piece of string. The diameter of the DNA molecule is about 2-3 nanometers (about a billionth of an inch) while the length can exceed a thousand micrometers (0.025 inch) in some organisms. One of the major challenges in molecular biology is how this giant molecule can be packaged into a cell or virus that is far smaller than the length of the DNA molecule. In addition, a number of investigations are concerned about how the cell is able to access the DNA molecule for the purposes of genetic control, routine cellular maintenance, and reproduction.