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IDT unveils new solution to accelerate homology-directed repair genome editing research

Feb 8, 2022
Alt-R™ HDR Donor Blocks cater to market demand for better homology-directed repair research solutions

CORALVILLE, Iowa (Feb. 1, 2022) — Global genomics solutions provider Integrated DNA Technologies (IDT) is empowering researchers to drive scientific discoveries in gene editing with the release of Alt-R HDR Donor Blocks, an improved solution for increasing homology-directed repair (HDR) rates in large fragment knock-in experiments. IDT’s Alt-R HDR Donor Blocks incorporate advanced chemical modifications to boost the HDR rates of large genomic changes and insertions, and significantly reduce the occurrence of non-homologous (blunt) integration of the donor sequence. Orders can be placed at

“It is well established that a key challenge in precise genome editing research is the low efficiency of HDR rates, and our new solution is singularly focused on helping researchers make HDR experiments more efficient and more likely to succeed,” said Mark Behlke, IDT’s Chief Scientific Officer. “Alt-R HDR Donor Blocks are the latest examples of products resulting from extensive wet-bench research conducted by IDT’s R&D scientists. We hope this new product can help increase research yields for the scientific community and serve as a gateway to repairing disease-causing mutations, altering genomes, and enabling more discoveries.”

In a study, IDT investigated the impact on HDR efficiencies when inserting a green florescent protein tag using long, single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA) templates. The results demonstrated that the use of Alt-R HDR Donor Blocks resulted in the highest HDR rates compared to unmodified dsDNA or long ssDNA. The ability of Alt-R Donor Blocks to reduce the occurrence of unwanted off-target integrations also was investigated. In addition, results showed a 65% reduction in blunt insertions at a mock off-target double strand break compared to unmodified dsDNA. When combined with IDT’s Alt-R HDR Enhancer v2, modified Alt-R Donor Blocks exhibited the highest HDR rates at multiple genomic loci and in multiple cell lines tested, and reduced the off-target integration, lowering blunt insertion levels to 1%.

Ann Morris, PhD, an associate professor at the University of Kentucky, added, “We worked with IDT on a project to generate knock-in zebrafish carrying an in-frame epitope tag in our gene of interest. In-frame knock-ins are notoriously difficult to obtain in zebrafish, but IDT helped us design several candidate donor templates with various modifications to determine which one would work best. The IDT Alt-R HDR Design Tool was easy to work with, and we were able to rapidly test several permutations of HDR donor blocks to successfully obtain our desired knock-in line. IDT staff gave us a lot of helpful advice, and were readily available throughout the process to answer our questions and get feedback on what worked best. We will definitely work with them again on our next knock-in project.”

IDT’s Alt-R HDR Donor Blocks are available from 201 to 3,000 bases in length, and are generated from clonally purified DNA, and utilize the same high-fidelity process as IDT gBlocks™ HiFi Gene Fragments. Benefits include:

  • Modifications that increase successful HDR events
  • Lower unintended blunt integrations at on- and off-target sites
  • Sequence verification by next generation sequencing
  • Higher HDR rates when combined with the Alt-R HDR Enhancer v2

“Successful CRISPR-mediated knock-in has been a challenge, but I have had great success with IDT’s Alt-R HDR Enhancer v2 and Alt-R HDR Donor Blocks,” said Ravi Nath, a postdoctoral scholar in genetics at Stanford University. “They were critical for generating key lines for my experiments.”

Alt-R HDR Donor Blocks are the latest addition to IDT’s complete portfolio of Alt-R™ CRISPR genome editing solutions and are designed to meet the evolving needs of researchers who are continuing to push the field of genome editing forward. Earlier this year, IDT launched the rhAmpSeq™ CRISPR Analysis System, an end-to-end solution for characterizing and quantifying the full array of on- and off-target genome editing events in CRISPR research products. IDT’s Alt-R CRISPR portfolio is comprised of solutions to meet researchers’ complete workflow — from design to analysis — to enable research projects through quality, simplicity, and cost efficiency.

About IDT

Integrated DNA Technologies, Inc. (IDT) develops, manufactures, and markets nucleic acid products for the life sciences industry in the areas of academic and commercial research, agriculture, medical diagnostics, and pharmaceutical development. IDT has developed proprietary technologies for genomics applications such as next generation sequencing, CRISPR genome editing, synthetic biology, digital PCR, and RNA interference. Through its GMP services, IDT manufactures products used by scientists researching many forms of cancer and most inherited and infectious diseases. IDT is widely recognized as the industry leader in custom nucleic acid manufacture, serving over 130,000 life sciences researchers. IDT was founded in 1987 and has its manufacturing headquarters in Coralville, Iowa, USA, with additional manufacturing sites in San Diego, California, USA; Research Triangle Park, North Carolina, USA; Ann Arbor, Michigan, USA; Leuven, Belgium; and Singapore. For more information, please visit and follow on Twitter, LinkedIn, Facebook, YouTube, and Instagram.


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