Question

Question TWO:

* From your knowledge about DNA microarray, answer the following:

A- How DNA microarray is created? and why it is referred to as “hybridization technology”?

B- Why RT-PCR is important in the sample preparation to perform expression microarray experiment?

C- Mention the name and the color of the dyes used in expression microarray?

Answer 1

Question no 1

A typical microarray experiment involves the hybridization of an mRNA molecule to the DNA template from which it is originated. Many DNA samples are used to construct an array. The amount of mRNA bound to each site on the array indicates the expression level of the various genes. This number may run in thousands.

The principle behind microarrays is that complementary sequences will bind to each other. The unknown DNA molecules are cut into fragments by restriction endonucleases; fluorescent markers are attached to these DNA fragments. These are then allowed to react with probes of the DNA chip.

Part b

The core principle behind microarrays is hybridization between two DNA strands, the property of complementary nucleic acid sequences to specifically pair with each other by forming hydrogen bonds between complementary nucleotide base pairs.