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Array Comparative Genomic Hybridization Array CGH for Detection of Genomic Copy Number Variants
Published on: February 21, 2015
Correcting positional correlations in Affymetrix® genome chips.
Dirar Homouz1, Gang Chen2, Andrzej S Kudlicki3
1Khalifa University of Science, Technology and Research, Abu Dhabi, UAE.
A new systematic error on Affymetrix microarrays causes spurious correlations based on probe distance. Researchers developed a correction algorithm to improve accuracy in gene expression data analysis.
Area of Science:
- Genomics
- Bioinformatics
- Microarray Technology
Background:
- Affymetrix microarrays are widely used for gene expression analysis.
- Systematic errors can impact the reliability of correlation analyses in large datasets.
- Previous studies have not identified this specific distance-dependent artifact.
Purpose of the Study:
- To report and model a novel systematic error in Affymetrix microarrays.
- To investigate the impact of probe distance on correlation measurements.
- To develop and validate a method for correcting this positional artifact.
Main Methods:
- Statistical modeling of probe-pair correlations on microarrays.
- Analysis of distance-dependent artifacts across different chip designs.
- Development and implementation of a bias correction algorithm.
Main Results:
- A previously undescribed systematic error causing spurious excess correlations was identified.
- The artifact is dependent on the physical distance between probes on the microarray.
- The yeast S98 microarray exhibited particularly high levels of this positional artifact.
Conclusions:
- The identified positional artifact can significantly affect correlation analyses in gene expression studies.
- A novel algorithm effectively corrects this bias, preserving data integrity.
- The corrected datasets enhance the reliability of downstream analyses of genomic data.

