Answer to Question #199602 in Genetics for Sam

Question

Concentrate on the potential use of DNA technologies in solving future problems in medicine and industry. Discuss the reliability, cost and some advantages and disadvantages of the techniques (techniques such as microarray technology, protein analysis, Southern blotting, Western blotting, etc).

Answer 1

Advantages

The microarrays have become important because they are easier to use, do not require large-scale DNA sequencing and allow the parallel quantification of thousands of genes from multiple samples

Disadvantages

The most significant disadvantages of microarrays include the high cost of a single experiment, the large number of probe designs based on sequences of low-specificity, as well as the lack of control over the pool of analyzed transcripts since most of the commonly used microarray platforms utilize only one set of probes designed by the manufacturer. Other weaknesses of microarrays are their relatively low accuracy, precision and specificity as well as the high sensitivity of the experimental setup to variations in hybridization temperature, the purity and degradation rate of genetic material, and the amplification process which, together with other factors, may impact the estimates of gene expression.

Reliability

in the context of DNA microarrays, refers to the ability of a probe to bind to a unique target sequence. A specific probe will provide a signal that is proportional to the amount of the target sequence only. A non-specific probe will provide a signal that is influenced by the presence of other molecules. The specificity of a probe can be diminished by cross-hybridization, a phenomenon in which sequences that are not strictly complementary according to the Watson–Crick rules bind to each other. Cross-hybridization is also called non-specific hybridization.