Genotyping Microarray

Revisionato il 08/07/2026

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- Cosa è il genotyping- Genotyping con microarray- Come funzionano i microarray- cosa sono i microarray (overview: supporto, probes, filamenti legati, ibridazione)- costruzione supporti …

Esame Elements of medical genetics andgenomics

Facoltà Ingegneria

Dal corso del Prof. Rizzo Francesca

Università Università degli Studi di Salerno

A.A. 2019-2020

37 pagine

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Genotyping Microarray

Process to determine genotype differences

The genotype of an individual is determined by examining the individual's DNA sequence and comparing it to another individual's sequence or a reference sequence.

How microarrays work

What are microarrays

Microarrays are laboratory tools used to detect the expression of thousands of genes at the same time. They involve a collection of slides printed with thousands of microscopic spots containing DNA fragments, known as probes, which are used to hybridize a cDNA sample and are fixed to the support.

Construction

Oligonucleotides are synthesized in situ and are called so because beams of light and photolithographic masks are used to create them directly on the array. In other cases, probes are synthesized in another location and then spotted on the array.

Sample preparation

Isolate mRNA
Mix samples
Collect tissue
Isolate RNA
Make labeled DNA copy

For example, you may have cancerous or normal tissue samples. The labeled DNA copy is typically marked with Cy5 (red) or Cy3 (green).

Hybridization

cDNA molecules bind to the DNA probes on the slide due to the property of complementary nucleic acid sequences to pair with each other. A high number of complementary base pairs means tighter non-covalent bonding between strands. After washing off non-specific bonding sequences, only strongly paired strands will remain hybridized.

Data analysis

Why do we obtain yellow? The yellow color is obtained due to the overlapping of red and green signals, indicating equal expression levels of the target genes in both samples.

Applications

Oncology
Pharmacogenomics
Microbiology

Oncology

Compare different patterns of gene expression
Map genetic abnormalities in a wide range of tumors

Advantages of microarrays

Small support and few reagents needed
Rapid and automatic method
Can screen many genes
Allows direct and parallel comparisons between different genes
Provides a great amount of information in a short time
Non-toxic and non-radioactive

Microarrays are a powerful tool in cancer research for identifying gene expression patterns and discovering genetic abnormalities in tumors.

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