makecdfenv

makecdfenv constructs CDF-based mapping environments and identifies probes affected by sequence variants (e.g., SNPs and indels) to improve preprocessing of Affymetrix microarray gene expression data.

Key Features:

• Probe Set Mapping: Reads an Affymetrix chip description file (CDF) and constructs a hash table environment that maps probe locations to probe sets.
• Automatic Environment Loading: Creates a package that automatically loads the mapping environment for use in R/Bioconductor workflows.
• Detection and Characterization of Probes: Detects probes within probe sets that exhibit differential hybridization due to sequence differences such as SNPs and indels and characterizes them.
• Error Reduction in Data Analysis: Characterizes and removes problematic probes to reduce type 1 and type 2 errors and routinely detect a higher percentage of known SNPs/indels with minimal false positives.
• Enhanced Differential Expression Analysis: Removes probes with differing binding affinities to improve accuracy of differential expression detection and reduce artifacts in comparative studies such as between cancerous and healthy tissues.

Scientific Applications:

• Microarray Data Preprocessing: Provides preprocessing of Affymetrix microarray data to produce higher-quality datasets for downstream analysis.
• Genomic Research: Enables more precise gene expression measurements by identifying and filtering problematic probes, supporting genomic studies.
• Cancer Research: Reduces artifacts in tissue comparisons to aid differential expression analyses between cancerous and healthy tissues.

Methodology:

Identifies probes affected by sequence differences by correlating signal intensities of probes within probe sets.