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DNA Fragment Synthesis
A one-stop gene synthesis solution covering codon optimization, sequence assessment, and complete plasmid delivery. No labor-intensive molecular cloning is required—simply provide your DNA or amino acid sequence,
and we will deliver the construct you need.
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  • > 96%

    On-time delivery rate

  • 200+

    Complimentary vector options

  • Sanger

    Results subject to the sequencing report

  • 1-7%

    Fastest delivery time

首页 > Products > Gene Synthesis > DNA Fragment Synthesis >
Introduction
Product Advantages
Service Details
Complex Sequence Assessment and Optimization
Service Workflow
Delivery Standards
Applications
Free Vectors
FAQ

Gene Synthesis

A Faster, More Flexible Alternative to Traditional Cloning

Traditional gene acquisition relies on cDNA library retrieval and PCR amplification, a cumbersome process limited by sample availability and sequence complexity. DNA fragment synthesis (full-length gene synthesis) combines chemical synthesis with enzymatic assembly to support multiple types of custom DNA sequences. Complex sequences require feasibility assessment; no template or sample is needed—only the target sequence.

We provide end-to-end custom gene synthesis services from sequence design through plasmid delivery. Whether the target is a conventional coding sequence or a challenging sequence with high GC content, repeats, or hairpin structures, it can be synthesized and cloned into the vector you require.

  • Reverse design and codon optimization from an amino acid (protein) sequence
  • No template DNA required; fully chemical synthesis without sample-source limitations
  • Faster than traditional molecular cloning, with turnaround as short as 1–7 calendar days
  • Sequence accuracy verified by Sanger sequencing, with a complete sequencing report

Product Advantages

Reliable, efficient, and cost-effective gene synthesis backed by a mature technology platform and quality control system
  • High Delivery Rate and On-Time Commitment
    More than 96% of projects are delivered on time in accordance with the committed schedule. Conventional sequences (<400 bp) can be delivered in as little as 1–7 calendar days, helping research move forward faster.
  • 200+ Free Vector Library
    More than 200 cloning and expression vectors are available at no additional charge, including prokaryotic expression systems (pET, pGEX, and others), mammalian expression vectors, yeast expression vectors, and commonly used cloning vectors. No separate vector purchase is required.
  • Sanger Sequencing; Results Are Based on the Sequencing Report
    Delivered sequences are verified by Sanger sequencing, with results based on the sequencing report. Standard sequence files, chromatograms (.ab1), and sequence alignment reports are provided for full traceability.
  • Complimentary Codon Optimization
    For customers providing amino acid sequences, codon optimization is included at no additional charge. Codon usage is adapted to the target expression host (E. coli, yeast, mammalian cells, insect cells, etc.), while GC content, repeats, and rare codons are optimized to improve protein expression.
  • Expertise in Challenging Sequences
    For challenging sequences with high GC content (>80%), low GC content (<20%), long repeats, palindromic structures, poly tracts, and related features, mature optimization strategies and synthesis solutions are available. The delivery plan is confirmed after sequence assessment.
  • Strict Confidentiality and Data Security
    All gene sequences and related information supplied by customers are kept strictly confidential. Without written authorization, sequences will not be disclosed, developed, or used in any form, protecting researchers’ intellectual property.

Service Details

Reliable, efficient, and cost-effective gene synthesis backed by a mature technology platform and quality control system
Sequence Type Sequence Length Turnaround Time (Calendar Days) Notes
Conventional Sequence
 ≶400 bp 1-7 Standard synthesis schedule; expedited service may be available
≶1.2 kb 7-10 Conventional coding sequences, promoters, and related elements
1.2kb - 2kb 10-15 Medium-length gene sequences
2 kb - 3 kb 15 - 20 Longer gene sequences assembled in segments
3kb - 4.5kb 20-25 Long gene fragments assembled from multiple segments
4.5kb - 5kb 25-30 Large-fragment gene synthesis requiring multiple rounds of assembly and verification
>5kb
Contact Us
 For ultra-long fragments, turnaround time and
Challenging Sequence
 1kb - 5kb
Contact Us
 High GC content, repeats, hairpin structures, and similar features require a customized solution
>5kb
Contact Us
 For exceptionally challenging fragments, contact us for a feasibility assessment

The above timelines apply to delivery in standard vectors (such as the pUC57 series) and conventional hosts (E. coli DH5a). Specifying a special vector or host may extend the turnaround time; contact technical support for details.

Complex Sequence Assessment and Optimization

Not every sequence can be synthesized smoothly—our expert team performs a comprehensive assessment before synthesis
01. Sequence Complexity Factors

The following factors may affect synthesis success and turnaround time:

  • Overall GC content below 20% or above 80%
  • Strong local fluctuations in GC content
  • Homopolymer sequences (such as continuous polyA/polyT >15 bp)
  • Direct or inverted repeats ≥20 bp
  • Palindromic sequences and hairpin structures (low ΔG)
  • Potential toxicity to the host cell
02. Optimization Strategies

For challenging sequences, we provide the following solutions:

  • Codon Optimization: Adjust codon usage without changing the amino acid sequence to reduce problematic GC content or repeats
  • Segmented Synthesis Strategy: Divide a long fragment into feasible segments for separate synthesis and subsequent assembly
  • Low-Copy Vector Selection: Use a low-copy-number vector for toxic genes to improve host stability
  • Specialized Host Strains: Select a host strain better suited to cloning challenging sequences
  • Manual Design Adjustment: Where necessary, fine-tune noncoding regions to remove structural barriers
03. Complimentary Sequence Assessment

An assessment is available before order submission:

  • Submit your target sequence and we will complete awithin 1 business daycomplimentary complexity assessment
  • The assessment report includes GC-content analysis, repeat identification, and potential structure prediction
  • Optimization recommendations and a customized synthesis plan
  • Clear quotation and turnaround time with no hidden charges

Service Workflow

Four straightforward steps from sequence to plasmid
  • Submit the Sequence
    Provide the DNA sequence or amino acid sequence together with the target expression host information, and submit it by email or through the online form.
  • Sequence Assessment and
    Quotation
    Within 1 business day, sequence analysis, complexity assessment, and codon-optimization recommendations are completed, followed by a detailed quotation and estimated turnaround time.
  • Gene Synthesis and
    Cloning
    After order confirmation, the process begins: oligonucleotide synthesis → fragment assembly → vector cloning → Sanger sequencing verification.
  • Delivery and After-Sales Support
    Plasmid DNA (lyophilized or liquid) and glycerol stocks are delivered with complete sequencing reports and quality documentation, followed by ongoing technical support.

Delivery Standards

Every order is delivered to defined standards so downstream experiments can begin promptly
  • Plasmid DNA
    Deliver 5 pg of high-purity plasmid DNA containing the target fragment, available as lyophilized powder (for convenient ambient-temperature shipping and long-term storage) or as a liquid.
  • Glycerol Stock (Optional)
    Provide a glycerol stock carrying the target plasmid (E. coli DH5a or another specified host), stored at −80°C for recovery when needed.
  • Standard Sequence Files
    Provide the final synthesized sequence in FASTA/GenBank format with clear annotation of the vector backbone and insert.
  • COA Quality Report
    Provide a Certificate of Analysis recording key parameters such as plasmid concentration, purity (A260/A280), and delivery amount.
  • Sequencing Results
    The delivered sequence is verified by Sanger sequencing, with results based on the sequencing report. Raw chromatograms (.ab1) and a sequence alignment report (.pdf) are provided.
  • Plasmid Map
    Provide a complete plasmid map annotated with key elements including the origin of replication, selection marker, and multiple cloning site (MCS).

Applications

Gene synthesis supports a wide range of life-science and biotechnology applications

Basic Life-Science Research

Gene cloning, subcloning, site-directed mutagenesis, gene function studies, and protein structure and function analysis, providing researchers with a flexible and efficient way to obtain genes.

Antibody Drug Discovery

Antibody gene synthesis, humanization, scFv/Fab construction, and bispecific antibody design. Codon optimization improves antibody expression and accelerates candidate screening.

Vaccine Development

Antigen gene synthesis, DNA vaccine construction, and mRNA vaccine template preparation. Supports rapid responses to emerging pathogens and sequence optimization to enhance immunogenicity.

Synthetic Biology

Metabolic pathway construction, genetic circuit design, and artificial chromosome assembly, supporting DNA synthesis from individual gene fragments to complete metabolic pathways.

Protein Engineering

Directed evolution, rational design, and fusion protein construction. Codon optimization and sequence design support efficient soluble expression of target proteins.

Agricultural Biotechnology

Transgenic crop development, molecular breeding, and resistance-gene synthesis, with plant codon optimization for compatibility with plant expression vectors.

Gene Editing

CRISPR/Cas9 system construction, sgRNA expression vectors, and HDR donor-template synthesis, providing DNA elements required for editing tools.

Gene Therapy

AAV/lentiviral vector construction and therapeutic gene synthesis, including specialized elements such as ITR sequences for preclinical research.

Free Vector Library

200+ vectors available at no additional charge across major expression systems
Prokaryotic Expression Vectors
  • pET series (T7 promoter, His-tag/GST-tag, etc.)
  • pGEX series (GST fusion expression)
  • pMAL series (MBP fusion expression)
  • pCold series (cold-shock expression system)
  • BAD series (arabinose-inducible expression)
Mammalian Expression Vectors
  • pcDNA3.1 series (CMV promoter)
  • pCMV series (multiple tag options)
  • pEF series (EF-1a promoter)
  • pIRES series (bicistronic expression)
  • Lentiviral Packaging Vector Systems
Cloning and Specialized Vectors
  • pUC57/pUC19/pUC18 (high-copy)
  • pBluescript series
  • T vectors (TA cloning)
  • Yeast expression vectors (pYES2, etc.)
  • Insect baculovirus expression vectors

If these vectors do not meet your needs, you may provide your own vector by mailing the plasmid or supplying its sequence. We will clone the target gene into the specified vector at no additional charge.

FAQ

Common Questions About Gene Synthesis
How does gene synthesis differ from traditional PCR cloning?
Traditional PCR cloning relies on existing template DNA, such as a cDNA library or genomic DNA. Gene synthesis is based on chemical synthesis, requires no template, starts from nucleotide monomers, and supports multiple types of custom DNA sequences. Complex sequences require feasibility assessment. This gives gene synthesis distinct advantages in the following situations:
  • · Genes from rare samples or without an available template
  • · Sequences requiring extensive codon optimization
  • · Artificially designed synthetic biology elements
  • · Sequences containing toxic or difficult-to-amplify structures
I only have a protein amino acid sequence, not a DNA sequence. Can the gene still be synthesized?
Yes. Provide the amino acid sequence and target expression host, such as E. coli or HEK293 cells. We will perform codon optimization at no additional charge, reverse-translate it into a DNA sequence, and then synthesize the gene.
How is the accuracy of a synthesized gene verified?
All synthesized genes undergo full-length Sanger sequencing verification before delivery, with results based on the sequencing report. Raw sequencing chromatograms (.ab1) and a sequence alignment report are provided, and customers may also use an independent third-party sequencing service.
Can you synthesize challenging sequences, such as high-GC or repetitive sequences?
Yes. We have established optimization strategies and synthesis solutions for sequences with high GC content (>80%), low GC content (<20%), long repeats, hairpin structures, and other complex features. Submit the sequence for a complimentary assessment, and we will respond within 1 business day with a feasibility analysis and customized plan.
Will my sequence remain confidential?
Customer information is managed under strict confidentiality. Without written authorization, your sequence will not be disclosed, developed, or used in any form. A nondisclosure agreement (NDA) can be signed upon request.
Can the delivered plasmid be used directly in downstream experiments?
Yes. The delivered plasmid DNA meets molecular biology–grade purity requirements (A260/A280 ≈ 1.8–1.9) and can be used directly for:
  • · Transfection/transformation experiments
  • · Restriction digestion analysis
  • · PCR amplification (as a template)
  • · In vitro transcription (IVT)
  • · Sequencing verification

For applications requiring higher purity, such as transfection-grade or in vivo injection-grade material, contact us to select an upgraded service.
What happens if a problem occurs during synthesis?
If the sequence itself makes synthesis difficult, our technical team will contact you, provide optimization recommendations such as codon adjustment or a segmented strategy, and discuss an appropriate solution. If sequencing confirms a mutation in the delivered sequence that is not caused by the customer’s original design and is verified as our quality issue, the sequence will be resynthesized at no additional charge in accordance with the agreement.

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