Technical demonstration of whole genome array comparative genomic hybridization

Area of Science:

• Genomics
• Molecular Biology
• Cancer Research

Background:

• Array comparative genomic hybridization (array CGH) is a key technology for identifying genomic gains and losses.
• High-resolution genome-wide comparisons are crucial for diagnosing genetic diseases and cancer.
• Existing methods require significant DNA input and struggle with sample heterogeneity.

Purpose of the Study:

• To introduce and detail the Sub-Megabase Resolution Tiling-set (SMRT) array for high-resolution array CGH.
• To demonstrate the SMRT array's capability in detecting various DNA alterations.
• To highlight the utility of SMRT arrays with challenging sample types.

Main Methods:

• Utilized the SMRT array, comprising ~30,000 overlapping bacterial artificial chromosome (BAC) clones spanning the human genome.
• Employed competitive hybridization with differentially labeled sample and reference DNA (Cyanine-3/Cyanine-5).
• Processed data using the SeeGH software for visualization of log2 signal intensity ratios.

Main Results:

• The SMRT array achieved sub-megabase resolution, detecting alterations as small as 50 kb.
• Successfully identified DNA gains, losses, amplifications, and homozygous deletions.
• Demonstrated effective profiling using DNA from formalin-fixed paraffin-embedded (FFPE) samples with low input requirements (25-100 ng).

Conclusions:

• The SMRT array platform provides a robust method for high-resolution genome-wide copy number profiling.
• Its ability to utilize FFPE DNA and tolerate tissue heterogeneity makes it ideal for precious and complex samples.
• This technology advances the detection of genetic alterations in various diseases.