Background
A DNA chip (also known as a gene chip, genome chip, or microarray) is used in the study of genes and how they affect cell functions. It is a solid glass slide containing a pattern of spots, each of which is a copy of a certain gene. To compare, for example, cancerous and noncancerous tissue, scientists label each with a different colored dye and apply them to the DNA chip. Each labeled gene attaches to its compliment on the chip; the brighter the resulting color, the stronger the gene is expressed in that specific tissue. A computer is used to see which genes are expressed in cancerous tissue (marked in one color), which in healthy tissue (marked in another), and both (a mix of the two colors). Genes expressed in the cancerous tissue but not in the healthy tissue could be important and require further examination.
Procedure
- Obtain miniature "microarray"
- Add 20µl of each sample of cDNA, incubated at 70°, to each spot of the microarray
- Add 20µl of hybridization solution to each sample
- Observe results
Results
Samples 3 and 6 were blue. Those genes are expressed only in healthy cells.
Sample 2 was purple, meaning it is expressed in both healthy and cancerous cells.
Sample 4 was purple. It is not expressed at all in lung cells.
Samples 1 and 5 were pink, meaning they are expressed only in cancer cells. Sample 1 was more vivid, meaning it is more likely to be an important factor than sample 5.
