Short oligonucleotide probes containing G-stacks display abnormal binding affinity on Affymetrix microarrays

Area of Science:

• Genomics
• Molecular Biology
• Bioinformatics

Background:

• Probe design is crucial for accurate microarray measurements.
• Current probe selection relies on in silico methods.
• Observed microarray data is underutilized for probe design feedback.

Purpose of the Study:

• To develop a method for assessing individual probe performance using existing microarray data.
• To identify probe characteristics that correlate with poor performance.
• To provide insights for improving future microarray probe design.

Main Methods:

• Assessed probe performance based on signal concordance among probes targeting the same gene.
• Analyzed probe behavior using the positional dependent nearest neighbor model.
• Examined probe performance in both gene expression and genotyping assays on Affymetrix microarrays.

Main Results:

• Probes with consecutive guanines (G-stacks) exhibit abnormal binding behavior.
• G-stack probes show reduced covariance with other probes for the same gene.
• G-stack probes are more likely to be outliers in binding affinity models, suggesting increased cross-hybridization and reduced specificity.

Conclusions:

• G-stacks in probes can lead to inaccurate microarray results due to aberrant binding.
• The developed probe performance assessment method can identify problematic probes.
• Findings offer valuable feedback for optimizing microarray probe design and data analysis strategies.