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Biochemistry

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Purines, Pyrimidines and Nucleic Acid Metabolism

Question
34 out of 59
 

Which technique is used for detecting genetic transfer of disease? (AIPG 2010)



A Northern blot
B Southern blot

C Western blot
D Micro array

Ans. D Micro array

Explanation:

a. A DNA microarray is a multiplex technology used in molecular biology and in medicine. It consists of an arrayed series of thousands of microscopic spots of DNA oligonucleotides, called features, each containing picomoles (10−12 moles) of a specific DNA sequence, known as probes (or reporters).

b. This can be a short section of a gene or other DNA element that are used to hybridize a cDNA or cRNA sample (called target) under high-stringency conditions. Probe-target hybridization is usually detected and quantified by detection of fluorophore-, silver-, or chemiluminescence-labeled targets to determine relative abundance of nucleic acid sequences in the target.

c. An array can contain tens of thousands of probes, a microarray experiment can accomplish many genetic tests in parallel. Therefore arrays have dramatically accelerated many types of investigation.

d. Microarray technology evolved from Southern blotting, where fragmented DNA is attached to a substrate and then probed with a known gene or fragment. In standard microarrays, the probes are attached via surface engineering to a solid surface by a covalent bond to a chemical matrix (via epoxy-silane, amino-silane, lysine, polyacrylamide or others).

e. The solid surface can be glass or a silicon chip, in which case they are commonly known as gene chip or colloquially Affy chip when an Affymetrix chip is used. Other microarray platforms, such as Illumina, use microscopic beads, instead of the large solid support.

f. DNA arrays are different from other types of microarray only in that they either measure DNA or use DNA as part of its detection system.

g. DNA microarrays can be used to measure changes in expression levels, to detect single nucleotide polymorphisms (SNPs) , to genotype or resequence mutant genomes

h. An alternative to microarrays is serial analysis of gene expression, where the transcriptome is sequenced allowing a absolute measurement

i. DNA microarrays can be used to detect DNA (as in comparative genomic hybridization), or detect RNA (most commonly as cDNA after reverse transcription) that may or may not be translated into proteins. The process of measuring gene expression via cDNA is called expression analysis or expression profiling

Purines, Pyrimidines and Nucleic Acid Metabolism Flashcard List

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