cDNA and Microarrays

Individuals can be screened for genetic diseases and cancers by using cDNA and microarrays

  • This technology can also be used to investigate the protein expression pathways that lead to these conditions


  • Complementary DNA (cDNA) is a molecule synthesised from an mRNA template via reverse transcription
  • cDNA molecules represent gene sequences that are actively transcribed by a cell (as they were synthesised from mRNA) 
  • This makes them a valuable tool for determining expression patterns of proteins in normal and diseased states


  • A DNA microarray is a collection of microscopic DNA sequences (oligos) attached to a solid surface
  • These sequences represent fractions of a large library of genes that are present in a cell
  • If a gene is active within a cell, then the cDNA (produced from the mRNA transcript) will bind to its complementary oligo
  • If the cDNA has been fluorescently labeled, then the complementary oligo can be identified (along with the gene it represents)
  • If cDNA from healthy and diseased cells are labeled with different fluorophores, comparisons of gene expression can be made
  • Genes that are only active in a diseased or normal state will be of particular interest to scientists

DNA Microarray Overview