gBlocks® Gene Fragments—Related DECODED Articles

Easy gene assembly—gBlocks® custom dsDNA gene fragments

  • Highly versatile—gBlocks Gene Fragments can be used to easily and reliably assemble almost any sequence, and are compatible with most published cloning methods, including the Gibson Assembly® Method, and blunt-end or cohesive-end cloning protocols.
  • Easy isothermal gene assembly—Using the Gibson Assembly Method, multiple gBlocks Gene Fragments can be assembled into a larger gene construct, in a single reaction that takes about 1 hour. A simple, 20–80 nt sequence overlap is required when designing the gene fragments for assembly.
  • Affordable—gBlocks Gene Fragments are up to half
    the price of other synthetic gene constructs, making
    synthetic biology accessible to any lab.
  • Short delivery time—gBlocks Gene Fragments are typically
    shipped within 5–8 business days.
Figure 1. gBlocks® Gene Fragments make it easy to produce the correct synthetic genes. gBlocks Gene Fragments (n=43), ranging from 126 to 459 bp and with GC ratios between 40 and 70%, were synthesized and cloned into pIDTSMART-Amp by blunt-end cloning. Ligated plasmids were transformed into XL1Blue cells, and 3–25 clones for each gBlocks Gene Fragment were selected and sequenced using traditional Sanger sequencing. The average fidelity for all sequences analyzed was 90%, and for 40 out of 43 gBlocks Gene Fragments the correct sequence was observed in >80% clones. The high percentage of correct sequences obtained makes it easy to find your desired clone.

High-fidelity, double-stranded DNA sequences

gBlocks Gene Fragments are sequence-verified, double-stranded DNA fragments, 125–3000 bp in length, that enable easy gene construction or modification. They are synthesized using the highest fidelity synthesis methods, developed by IDT for our industry-leading Ultramer™ Oligonucleotides, making them ideal for a broad range of cloning techniques.

Screen fewer clones

Experimental data shows that 90% of cloned gBlocks Gene Fragments will have the correct sequence (Figure 1). In addition, using the Gibson Assembly method, two or more gBlocks fragments can easily be assembled in a single reaction to generate larger constructs [1] (Table 1). gBlocks Gene Fragments are synthesized without a 5’ phosphate; optional 5’ phosphorylation is available for blunt cloning.


Get gBlocks Gene Fragments quickly

The easy online ordering system allows sequences for gBlocks Gene Fragments to be entered individually or as multiple entries using a provided Microsoft Excel template. Orders typically ship within 5–8 business days. gBlocks Gene Fragments are delivered with a short protocol that summarizes cloning methods for experienced users. Complete assembly and cloning protocols are available under Support on the gBlocks Gene Fragments product page.


  1. Gibson DG, Young L, et al. (2009) Enzymatic assembly of DNA molecules up to several hundred kilobases. Nature Methods, 6(5):343–345.

Author: Hans Packer is a scientific writer at IDT.

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