Geochip Operations

GeoChip is a specific type of microarrays with each probe targeting a specific nucleic acid sequence or a group of highly similar sequences, and it can be constructed by spotting or in situ synthesis on a glass slide (Figure 4A). DNA or RNA is extracted from a sample, such as soil, water, or food, and labeled with a fluorescent dye. When the labeled DNA or RNA molecules come into contact with the appropriate probe, the DNA is Ą°capturedĄą by the probe (Figure 4B). After hybridization, free DNA/RNA molecules are washed away, and the signal intensity of the fluorescently labeled and captured DNA/RNA molecules is digitally imaged by a laser scanner (Figure 4C). This digital image is then used to assess the concentration or abundance of the target DNA/RNA. GeoChip can simultaneously measure many gene sequences from one sample.

Schematic presentation of GeoChip development and applications in analysis of microbial communities from a variety of habitats. A. GeoChip development; B. Target preparation; C. GeoChip data analysis (He et al., 2011).