gBlocks Gene Fragments

gBlocks Gene Fragments

100 % sequence Double-stranded, sequence-verified genomic blocks (ִ 3,000 bp, without vector)


▪▪gBlocks Gene Fragments ռ : 125-3,000 base pairs
▪▪Double stranded DNA
▪▪sequence: 100% ǰ
▪▪Amount: gBlocks Gene Fragments product ߼ (Ŭδ Ǵ qPCR control 迡 )
▪▪ϴ Ϳ ڰ Ŭδ
▪▪ռ Ⱓ: 6-7(ָ )
▪▪Spec sheet

gBlocks Gene Fragments

Available in lengths of 125–2000 bp
A, T, C or G residues only
Delivered dry, normalized to 200 ng
Fragments 125–750 bp, s 7-10 ҿ
Fragments 751–1000 bp, 2-3 ҿ

gBlocks Gene Fragments Libraries

Available in lengths of 251–500 bp
Up to 18 consecutive N or K residues
Delivered dry, normalized to 200 ng
3-4 ҿ


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▪▪5' Phosphorylation (߰ )
▪▪A/T/C/G DNA bases
▪▪Ÿ ռ Ǵ base ߰ ȵ

gBlocks Gene Fragments (2022.01.31 update)

Product Name Amount (ng)
gBlocks Gene Fragments 125-250 bp NEW 250
gBlocks Gene Fragments 251-500 bp 500
gBlocks Gene Fragments 501-750 bp 500
gBlocks Gene Fragments 751-1000 bp 1000
gBlocks Gene Fragments 1001-1250 bp 1000
gBlocks Gene Fragments 1251-1500 bp 1000
gBlocks Gene Fragments 1501-1750 bp 1000
gBlocks Gene Fragments 1751-2000 bp 1000
gBlocks Gene Fragments 2001-2250 bp NEW 1000
gBlocks Gene Fragments 2251-2500 bp NEW 1000
gBlocks Gene Fragments 2501-2750 bp NEW 1000
gBlocks Gene Fragments 2751-3000 bp NEW 1000

gBlocks Gene Fragments

gBlocks Gene Fragments are double-stranded DNA molecules of 125–1000 bp in length. gBlocks Gene Fragments are synthesized using the same industry-leading, high-fidelity synthesis chemistry developed by IDT for our Ultramer oligonucleotides, and are sequence verified prior to shipping. The high sequence fidelity and rapid delivery time make gBlocks Gene Fragments ideal for a range of synthetic biology applications, including the ability to easily assemble multiple gene fragments to reliably generate larger gene constructs.
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, 3 gBlocks Gene Fragments can be assembled in a single reaction into a 2.8 kb gene in less than 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 2–4 working days (3–5 days for fragments >750 bp).

gBlocks Gene Fragments Libraries

gBlocks Gene Fragments Libraries are pools of gBlocks Gene Fragments up to 500 bp in length that contain up to 18 consecutive variable bases (N or K). They are ideal tools for demanding applications such as generating recombinant antibodies or protein engineering.
Below is a representation of the general ordering format for gBlocks Gene Fragments Libraries
gblock library.jpg

Ordering format for gBlocks Gene Fragments Libraries

gBlocks Gene Fragments Libraries are entered the same way as gBlocks Gene Fragments. The ordering interface now accepts N or K (G or T) mixed bases when present in an acceptable format (K mixed bases placed in the third position of codons eliminate two of the three stop codons from being included in the gene fragments libraries). The gBlocks Gene Fragments Libraries can be 251 to 500 bp in total length, including the variable region. The variable regions can be up to 18 consecutive N or K bases long, and needs to be at least 125 bp from either end of the gene fragment.

Why did IDT limit the variable regions to 18 mixed bases?

When you order a gene fragment library that contains 18 "N" mixed bases, you order a pool of 418 gene fragments—about 68.7 billion different gBlocks Gene Fragments. This means that one can estimate that there will be about 4,000 copies of each gene fragment in the 200 ng of material provided. Increasing the diversity further would compromise the representation of each gene fragment in the pool.

How to use gBlocks Gene Fragments Libraries

gBlocks Gene Fragments Libraries can be used directly in some suitable applications such as In vitro transcription or when used as standard or internal controls for qPCR or NGS experiments. More often, they are assembled into functional genes or longer constructs by seamless assembly techniques or traditional restriction cloning.

Adding diversity at reasonable cost

For screening purposes, gBlocks Gene Fragments Libraries allow for the generation of hundreds of thousands of constructs at a fraction of the cost of generating variant libraries.

Quality Assurance

Each gBlocks Gene Fragment ordered from IDT will go through the following verification process:
1. Researchers enter the gene fragments sequences (125–1000 base pairs) on the gBlocks Gene Fragments order entry page. Only A/C/G/T bases can be entered; no mixed degenerate bases, no modified" bases (Inosine, Uridine)
2. Automated review by screening tools at the time of order entry and, and expert review by IDT scientists, of entered sequences for characteristics that may interfere with synthesis
3. Biosafety and regulatory conformance check
A biohazard disclosure statement is required for each gene order.
IDT reserves the right to refuse any order that does not pass this analysis. If one of your sequences does not pass the screen criteria, you will be contacted by a gene services specialist to determine the best way to proceed.

QC procedure and sequence verification

Each gBlocks Gene Fragment undergoes the following quality control procedures:
1. Size verification by capillary electrophoresis
2. Sequence identification by mass spectrometry
3. Final consensus sequence verification
This rigorous testing ensures that, in the majority of cases, >80% of recombinant colonies obtained from cloning each gBlocks Gene Fragment will contain the desired insert. More complex sequences may have reduced fidelity, which can be addressed by the end user sequencing additional clones.

For gBlocks Gene Fragments Libraries,

each constant region is verified as above. The final library product is size verified by capillary electrophoresis.

Guaranteed yield

gBlock Gene Fragments are delivered dry, normalized to 200 ng.


All sequence information is kept confidential at IDT.
All online ordering steps, including sequence entry and choice of parameters, are also secure and protected.

gBlocks Gene Fragment Applications

Gene Synthesis Applications

Highly versatile gBlocks Gene Fragments can be easily assembled and cloned into the vector of your choice using a wide variety of cloning methods, including the Gibson Assembly method, blunt-end and cohesive-end cloning protocols. For added flexibility, gBlocks Gene Fragments can be ordered with or without a 5-phosphate group; select the correct phosphorylation option based on cloning method.
Assembly Method
gBlock Gene Fragment Phosphorylation Note
 Isothermal Assembly  Un-Phosphorylated Requires a simple 20–80 bp overlap in DNA elements being joined. Can be used to join multiple gBlocks Gene Fragments in a single reaction.
 Restriction Cloning  Un-Phosphorylated Consider adding 6–8 nucleotides on each end of your gBlocks Gene Fragment to ensure efficient restriction digestion
 TOPO Cloning  Un-Phosphorylated For T/A cloning, gBlocks Gene Fragment needs to be adenylated using a Taq polymerase in presence of dATP
 Blunt-end Cloning  5-Phosphorylated Linearized vector must be 5-dephosphorylated

Possible applications of gBlocks Gene Fragments include, but are not limited to:

Protein Expression
Recombinant antibodies
Novel fusion proteins
Codon optimized short proteins
Functional peptides: catalytic, regulatory, binding domains
microRNA genes
Template for in vitro transcription (IVT)
Regulatory sequence cassettes
Microarray-ready cDNA
Gene variants and SNPs
DNA vaccines
Standards for quantitative PCR and other assays
Functional Genomics
Limitless flexibility for protein mutagenesis
Mutant libraries
Deletion mutants


Gibson D, Young L, et al. (2009) Enzymatic assembly of DNA molecules up to several hundred kilobases. Nature Methods, 6(5):343–345.
gBlock Gene Fragments ı~~~
ı ۼ
PrimeTime qPCR 5' Nuclease Assays (Probe)
PrimeTime qPCR Primer Assays (SYBR)