Random Substitutions

GeneArt® Controlled Randomization technology allows you to accurately direct the effective frequency of random nucleotide substitutions. And unlike error-prone PCR, you decide exactly which part(s) of the gene are affected—randomize the entire open reading frame or confine the mutagenesis to specific regions.

Randomized constructs are rigorously controlled to help ensure that the unchanged portions of the sequence are unaffected and that randomized portions contain the distribution of nucleotides you require to encode the amino acid composition you’re looking for.

Get Your Project Started

Please download the questionnaire to submit project information. For secure data transfer please register at our customer portal.

For further information regarding this service or the order process, please contact

Libraries Are Available Cloned or Ready to Clone

GeneArt® Controlled Randomization Ready-to-Clone Library
  • 5 µg of linear DNA ready to clone via 5' and 3' restriction sites
GeneArt® Controlled Randomization Cloned Library
  • 10 µg of plasmid DNA cloned into the vector of your choice
  • Includes glycerol stock of all library transformants


  • Diversify antigen-binding sites of antibodies
  • Improve physicochemical protein properties such as solubility, heat stability, and activity in industrial environments
  • Enhance function, such as promoter activity and enzymatic properties
  • Optimize antibody affinity (in vitro affinity maturation)
  • Humanize antibodies
  • Prolong half-life of therapeutics for in vivo environments
  • Improve enzymes for industrial use
  • Modify enantioselectivity of enzymes
  • Induce changes to alter proteins from patented sequences


  • Library diversity of up to 1011 variants
  • Precise selection of the average mutation rate (number of changes per construct)
  • Random mutagenesis throughout construct, or limited to defined positions
  • Transition/transversion ratio of 1:2
  • Fewer silent mutations
  • Low ancillary mutation rate
  • Fast production times

Quality Control

All GeneArt® Controlled Randomization products are sequenced and subjected to statistical analysis to help ensure that they meet the following quality benchmarks:

  • Sequencing of up to 96 individual transformants to verify that customer’s specifications regarding nucleotide content and amino acid encoding have been met, and that sequence integrity of unmutated portions of the construct meets minimum requirements
  • Bulk sequencing to verify that nondegenerated portions of the construct have the correct sequence and randomized portions meet customer’s specifications and maintain an open reading frame
  • Real-time PCR prior to amplification to verify that library diversity objectives have been me

For Research Use Only. Not for use in diagnostic procedures.