Synthetic genes ready to clone—and affordable for every lab
Whether you’re studying single gene or assembling larger fragments, we offer cutting-edge technology with our Invitrogen GeneArt DNA fragments to meet all your gene fragment needs. This includes the convenience of our online ordering system and Invitrogen GeneOptimizer technology for stable and increased protein expression.
With the introduction of our new GeneArt High-Q Strings technology, we help enable a high degree of accuracy when you really need it for fragments up to 1,200 bp without compromising significantly on production time. If you need longer fragments then you still have the great option of Strings DNA Fragments.
GeneArt High-Q Strings and Strings DNA Fragments and Libraries
| NEW High-Q Strings DNA Fragments | Strings DNA Fragments | |
|---|---|---|
| How to order | GeneArt Assistant | GeneArt Portal |
| Benefits | Unparalleled accuracy | Faster turnaround time |
| Length (base pairs) | 200 – 1,200 | 200 – to 3,000 |
| Accuracy (error per base) | less than 1 in 10,000 | less than 1 in 5,000 |
| GC content | 30 – 70% GC some homopolymers excluded |
30 – 70% GC |
| Total reliability | 95% | 95% |
| Production time | 6 to 9 business days | 3 to 8 business days |
| Delivery amount (lyophilized DNA) |
Minimum > 200 ng Average 900 ng |
Minimum > 200 ng Average 900 ng |
| Price starting from | $59 | $99 |
Other ways to order
Learn about the latest in GeneArt technologies and how they compare
NEW–GeneArt High-Q Strings DNA Fragments are revolutionary custom DNA fragments developed to help provide unparalleled sequence accuracy and quality in the industry. Thermo Fisher Scientific’s cutting edge and innovative microchip technology platform coupled with high accuracy standards set through our Next Gen Sequencing quality control result in an error rate of less than 1 in 10,000 bp. The ultimate accuracy of High-Q Strings DNA Fragments make them ideal for multi-fragment high order assembly in combination with our GeneArt Assembly kit.
- Leading accuracy in the market with an error rate of less than 1 in 10,000 bp
- Order from single construct to high throughput size
- Direct use for high throughput assembly, no universal linker that needs intermediate cloning
- World’s leading gene optimization algorithm at complimentary rate
- Production time similar to cloned gene synthesis constructs
GeneArt High-Q Strings DNA Fragments are developed to combine the convenience of a PCR product with the potency of custom-made DNA – available with a leading and complimentary expression optimization at a very reasonable price. They are custom-made, uncloned, double-stranded linear DNA fragments from 200 to 1,200 base pairs in length. High-Q Strings DNA Fragments are delivered dried and ready for resuspension and cloning after minimum screening to help identify the correct clone.
GeneArt High-Q Strings products, production time, and price
| Product | Production time (business days)* | Price |
|---|---|---|
| DNA Fragments 200–500 bp | 6-9 | $59 |
| DNA Fragments 501–750 bp | 6-9 | $89 |
| DNA Fragments 751–1,000 bp | 6-9 | $114 |
| DNA Fragments 1,001–1,200 bp | 6-9 | $159 |
*Production time is the number of business days required to synthesize GeneArt High-Q Strings DNA Fragment products in our manufacturing facility. Delivery time is in addition to production time and depends on the destination of the shipment.
GeneArt High-Q Strings DNA Fragments features and benefits
Improved error rates
Table 1. Accuracy data derived from cloning between 11 and 32 linear DNA fragments from different suppliers (GeneArt Strings DNA Fragments, GeneArt High-Q Strings DNA Fragments, and linear DNA fragments from two competitors) and Sanger sequencing of individual clones. Error rates were calculated by dividing the total number of sequenced base pairs by the total number of found sequence errors.
| Product | Error rate |
|---|---|
| GeneArt High-Q Strings DNA Fragments | less than 1 in 10,000 |
| GeneArt Strings DNA Fragments | less than 1 in 5,000 |
| Supplier 1 and 2 | less than 1 in 2,000 |
Reduced screening efforts
GeneArt High-Q Strings DNA Fragments reduce the required screening effort by at least 60% compared to competitor products and help enable direct assembly of 5 kb constructs with reasonable screening effort. Based on the error rates determined for the different products, we calculated the number of clones that need to be sequenced in order to identify a correct clone with a probability of 98% (Figure 1).
Since this number exponentially increases with the total size of the DNA fragment, differences in error rate become particularly substantial as fragments get longer.
High-Q Strings DNA Fragments reduce the required screening effort by at least 60% compared to competitor products, and enable direct assembly of 5 kb constructs with reasonable screening effort (Figure 2).
Figure 2. Number of clones required to choose the correct one using 3 different error rates. The impact of a lower error rate is shown as the insert length increases.
Cost saving
GeneArt High-Q Strings DNA Fragments significantly reduce required screening effort and associated costs, and result in overall cost savings of more than 30%.
| Supplier 1 | GeneArt High-Q Strings DNA Fragments | |
|---|---|---|
| 1000 bp | ||
| Screening and sequencing cost | $39.00 | $16.50 |
| DNA fragment cost | $149.00 | $114.00 |
| Total cost | $188.00 | $130.50 |
| Additional total cost over High-Q Strings | $57.50 | |
| % cost savings vs. Competitor | 30% |
Screening and sequencing costs were calculated from the number of clones required for the identification of a correct clone with the following assumptions: 90% of clones contain an insert of expected size; associated costs of $1.50 per colony PCR reaction and $3.00 per sequencing reaction; 1000 bp inserts require 2 sequencing reactions, 1500 bp and 2000 bp inserts require 4 sequencing reactions.
GeneArt Strings DNA Fragments are custom-made, uncloned, double-stranded linear DNA fragments from 200 base pairs (bp) to 3,000 bp in length, assembled from synthetic oligonucleotides using the same high-quality process developed for Invitrogen GeneArt Gene Synthesis. Strings DNA Fragments are delivered dried, ready for resuspension, cloning, and screening to enable the identification of the correct clone.
All GeneArt Strings DNA products can be designed, optimized for protein expression, and ordered within our online order portal for delivery in tube format.
- Affordable—cost-effective alternative to GeneArt Gene Synthesis or Combinatorial Libraries
- Flexible—full gene design and cloning flexibility; enter your sequence and directly edit, optimize, and order through our online portal
- Fast—production time starts at 5 business days
GeneArt Strings Assistant
With GeneArt Strings DNA Fragments, your custom gene sequence may occasionally not fit our production criteria due to regions of sequence complexity. To mitigate this, we have launched the online GeneArt Strings Assistant app within Thermo Fisher Cloud.
After uploading, your DNA sequences area analyzed and potential problems are identified. You can then manually edit the sequences or you can use the suggestions offered by the Assistant which includes the introduction of silent mutations.
Edited sequences can then be ordered as GeneArt Strings DNA Fragments.
On this page:
Complete usage instructions can be found in the GeneArt Strings product bulletin. Choose the PDF based on your location:
| Product | Production time (business days)* |
List Price | Price per bp |
|---|---|---|---|
| DNA Fragments 200–600 bp | 3-5 |
$99 | **As low as $0.15/bp USD for a 1 kb DNA fragment |
| DNA Fragments 601–750 bp | 3-5 |
$129 | |
| DNA Fragments 751–1,000 bp | 3-5 |
$149** | |
| DNA Fragments 1,001–1,250 bp | 4-6 | $219 | |
| DNA Fragments 1,251–1,500 bp | 4-6 | $259 | |
| DNA Fragments 1,501–1,750 bp | 4-6 | $299 | |
| DNA Fragments 1,751–2,000 bp | 4-6 | $349 | |
| DNA Fragments 2,001–2,250 bp | 6-8 | $399 | |
| DNA Fragments 2,251–2,500 bp | 6-8 | $449 | |
| DNA Fragments 2,501–2,750 bp | 6-8 | $499 | |
| DNA Fragments 2,751–3000 bp | 6-8 | $549 | |
| DNA Libraries: IUPAC ntd | 10-15 | $49 per ntd |
*Production time is the number of business days required to synthesize GeneArt Strings DNA products in our manufacturing facility. Delivery time is in addition to production time and depends on the destination of the shipment.
Strings DNA products are suspended in 10 mM Tris pH 8.5 buffer and delivered dried, ready for resuspension and cloning. We recommend that you centrifuge tubes prior to opening, add the appropriate amount of water to the bottom of the tube, and incubate at least 1 hour at room temperature (alternatively incubate at 4°C overnight). After incubation, carefully resuspend Strings DNA products and use immediately. If not used immediately, resuspended Strings DNA products should be aliquoted and frozen at –20°C. Please avoid freeze-thaw cycles.
Delivery amounts:
GeneArt Strings DNA Fragments: ≥ 200 ng
GeneArt Strings DNA Libraries: ≥ 500 ng
Figure 1 shows an image of nine Strings DNA Fragments and five Strings DNA Libraries resuspended and separated using agarose gel electrophoresis .
Figure 1. Strings DNA Fragments (lanes 1-4 and 6-10) and Strings DNA Libraries (lanes 12-16) after gel electrophoresis (1% agarose gel). Library 1 is 501 bp; Library 2 is 649 bp; Library 3 is 998 bp; Library 4 is 404 bp; and Library 5 is 1989 bp. DNA marker is 1 kb DNA Ladder.
The GeneArt production team performs a biosecurity screen on each sequence entered. In the event your order does not pass this analysis, you will be contacted to determine the best way to proceed.
Strings DNA products can be cloned using any available cloning method, just make sure to design the ends of your sequence according to the respective requirements. You can simply paste the sequence into the online order form of the web portal and proceed to the cart to order. Alternatively, you can use the convenient GeneArt portal sequence editing and optimization functions. Depending on your desired cloning system, you may need to modify the 5′ and 3′ ends of your sequence to enable proper insertion into your desired vector. For example, for cloning Strings DNA products by restriction enzymes/ligation, we generally recommend adding additional stuffer nucleotides to both ends of your sequence to ensure efficient enzyme binding. If blunt cloning methods are used (e.g., Invitrogen TOPO technology), we recommend that you add 5–10 nucleotides of random stuffer DNA on both ends of the fragment, preserving functional DNA elements needed for downstream applications (by their very nature, linear DNA fragments are not entirely free of small terminal truncations).
Table 1. Examples for cloning methods and recommended sequence design.
| Restriction enzyme cloning | Add desired 5′ and 3′ restriction enzyme sequences, plus stuffer nucleotides |
| GeneArt Type IIs Assembly | Add desired 5′ and 3′ restriction enzyme sequences, plus stuffer nucleotides |
| Invitrogen GeneArt Seamless Cloning and Assembly | Add 15 bp sequence overlap (or more, depending on the kit) to vector or adjacent insert |
| Invitrogen Gateway Cloning | Add attB sites to enable proper recombination into Invitrogen pDONR vector |
| Invitrogen Zero Blunt TOPO PCR Cloning | Strings Fragments are blunt ended, so 5–10 stuffer nucleotides are recommended to compensate for small terminal truncations |
| TA and Invitrogen TOPO TA Cloning | Strings Fragments are blunt-ended and need to be adenylated using a Taq polymerase in the presence of dATP to add end-terminal A-overhangs |
Strings DNA Fragments are PCR amplicons of assembled oligonucleotides, ready for screening to identify the correct clone. Strings DNA Fragments are bulk sequence-controlled as part of the QC process to help ensure that your desired sequence is present in the fragment pool. To identify a correct clone >90% of the time, we recommend to use the screening guidelines in Table 2.
Table 2. Recommended screening of Strings DNA Fragments.
| Strings DNA Fragments up to 1 kb | Sequence 2 to 4 full-length clones |
| Strings DNA Fragments 1–2 kb | Sequence 3 to 5 full-length clones |
| Strings DNA Fragments 2–3 kb | Sequence 4 to 8 full-length clones |
Screening recommendations and application examples
Restriction enzyme cloning example with GeneArt Strings DNA Libraries
All 5 libraries were cloned by restriction digest, ligation and transformation of E. coli by electroporation. Resulting colony forming units (cfu) were counted and a value for the cloning of 500 ng library was extrapolated (blue bars). Colony-PCR was performed on 16 colonies each and the cloning efficiency calculated as the percentage of colonies with an insert of expected size (red bars). Error bars indicate standard error of the mean from multiple experiments.
GeneArt Seamless Cloning and Assembly example with Strings DNA Libraries
All 5 libraries were cloned using the GeneArt Seamless Cloning and Assembly Kit with subsequent heat shock transformation of E. coli. Resulting colony forming units (cfu) were counted and a value for the cloning of 500 ng library was extrapolated (blue bars). Colony-PCR was performed on 16 colonies each and the cloning efficiency calculated as the percentage of colonies with an insert of expected size (red bars). Error bars indicate standard error of the mean from multiple experiments.
GeneArt Type IIs Assembly example with Strings DNA Libraries
All 5 libraries were cloned using the GeneArt Type IIs Assembly Kit AarI with subsequent transformation of E. coli by electroporation. Resulting colony forming units (cfu) were counted and a value for the cloning of 500 ng library was extrapolated (blue bars). Colony-PCR was performed on 16 colonies each and the cloning efficiency calculated as the percentage of colonies with an insert of expected size (red bars). Error bars indicate standard error of the mean from multiple experiments.
Restriction enzyme cloning example with GeneArt Strings DNA Fragments
Eight Strings DNA Fragments up to 3,000 bp were cloned using 5’ AscI and 3’ PacI restriction enzymes. After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Eight (<1 kb) or 16 (>1 kb) colonies were picked, and colony PCR was performed to identify full-length clones; four to eight full-length clones were sequenced to determine the number of sequence-correct clones.
GeneArt Type IIs Assembly example with multiple Strings DNA Fragments
Eight Strings DNA Fragments of different lengths up to 2,800 bp with suitable sequence ends (AarI recognition sequence and 6 bp stuffer nucleotides) were used for direct assembly with the GeneArt Type IIs Assembly Kit Aar I (Cat. No. A15916). The resulting four genes were 5,056 bp, 5,061 bp, 5,267 bp, and 5,448 bp long. After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Sixteen colonies were picked and colony PCR was performed to identify full-length clones. For all four assembled genes, eight colonies were sequenced to determine the number of sequence-correct clones.
GeneArt Seamless Cloning example with GeneArt Strings DNA Fragments
Ten Strings DNA Fragments up to 3,000 bp were cloned using the GeneArt Seamless Cloning and Assembly Kit (Cat. No. A13288). After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Eight (<1 kb) or 16 (>1 kb) colonies were picked, and colony PCR was performed to identify full-length clones; four to eight full-length clones were sequenced to determine the number of sequence-correct clones.
GeneArt Seamless Assembly example with multiple Strings Fragments
Strings DNA Fragments are offered in lengths up to 3,000 bp. However, GeneArt Seamless assembly technology can be used to directly assemble two Strings DNA Fragments up to 1 kb without pre-cloning of the subfragments. If you want to assemble more Strings DNA Fragments or longer Strings DNA Fragments using seamless assembly technology, we generally recommend pre-cloning of the subfragments to limit the screening effort needed to find the correct clone after assembly. Alternatively, you can use GeneArt Type IIs assembly technology.
Twelve Strings DNA fragments of different lengths up to 1 kb with suitable sequence ends (15 bp homology to the vector or to the next fragment) were used for direct assembly with the GeneArt Seamless Cloning and Assembly Kit (Cat. No. A13288). The resulting six genes were 1,375 bp, 1,466 bp, 1,536 bp, 1,590 bp, 1,647 bp, and 1,853 bp long. After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Sixteen colonies were picked, and colony PCR was performed to identify full-length clones. For all six assembled genes, six colonies were sequenced to determine the number of sequence-correct clones.
Gateway cloning example with GeneArt Strings DNA Fragments
Five Strings DNA Fragments up to 1,000 bp with attB sites were cloned into pDONR 221. After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Eight colonies were picked, and colony PCR was performed to identify full-length clones; four to seven full-length clones were sequenced to determine the number of sequence-correct clones.
The figure shows the percentage of clones with correct length as identified by colony PCR (cloning efficiency) and the percent of sequence-correct clones (fidelity) based on the number of full-length clones.
GeneArt Strings DNA Libraries
GeneArt Strings DNA Libraries are pools of GeneArt Strings DNA Fragments from 200–2000 bp, containing up to 3 blocks of degenerate nucleotides with randomized distribution. Each block can consist of up to 30 bp using the full IUPAC code of DNA nucleotides (U is not optional). Blocks need to be separated by 30 bp of non-degenerate nucleotides.
NEW–GeneArt High-Q Strings DNA Fragments are revolutionary custom DNA fragments developed to help provide unparalleled sequence accuracy and quality in the industry. Thermo Fisher Scientific’s cutting edge and innovative microchip technology platform coupled with high accuracy standards set through our Next Gen Sequencing quality control result in an error rate of less than 1 in 10,000 bp. The ultimate accuracy of High-Q Strings DNA Fragments make them ideal for multi-fragment high order assembly in combination with our GeneArt Assembly kit.
- Leading accuracy in the market with an error rate of less than 1 in 10,000 bp
- Order from single construct to high throughput size
- Direct use for high throughput assembly, no universal linker that needs intermediate cloning
- World’s leading gene optimization algorithm at complimentary rate
- Production time similar to cloned gene synthesis constructs
GeneArt High-Q Strings DNA Fragments are developed to combine the convenience of a PCR product with the potency of custom-made DNA – available with a leading and complimentary expression optimization at a very reasonable price. They are custom-made, uncloned, double-stranded linear DNA fragments from 200 to 1,200 base pairs in length. High-Q Strings DNA Fragments are delivered dried and ready for resuspension and cloning after minimum screening to help identify the correct clone.
GeneArt High-Q Strings products, production time, and price
| Product | Production time (business days)* | Price |
|---|---|---|
| DNA Fragments 200–500 bp | 6-9 | $59 |
| DNA Fragments 501–750 bp | 6-9 | $89 |
| DNA Fragments 751–1,000 bp | 6-9 | $114 |
| DNA Fragments 1,001–1,200 bp | 6-9 | $159 |
*Production time is the number of business days required to synthesize GeneArt High-Q Strings DNA Fragment products in our manufacturing facility. Delivery time is in addition to production time and depends on the destination of the shipment.
GeneArt High-Q Strings DNA Fragments features and benefits
Improved error rates
Table 1. Accuracy data derived from cloning between 11 and 32 linear DNA fragments from different suppliers (GeneArt Strings DNA Fragments, GeneArt High-Q Strings DNA Fragments, and linear DNA fragments from two competitors) and Sanger sequencing of individual clones. Error rates were calculated by dividing the total number of sequenced base pairs by the total number of found sequence errors.
| Product | Error rate |
|---|---|
| GeneArt High-Q Strings DNA Fragments | less than 1 in 10,000 |
| GeneArt Strings DNA Fragments | less than 1 in 5,000 |
| Supplier 1 and 2 | less than 1 in 2,000 |
Reduced screening efforts
GeneArt High-Q Strings DNA Fragments reduce the required screening effort by at least 60% compared to competitor products and help enable direct assembly of 5 kb constructs with reasonable screening effort. Based on the error rates determined for the different products, we calculated the number of clones that need to be sequenced in order to identify a correct clone with a probability of 98% (Figure 1).
Since this number exponentially increases with the total size of the DNA fragment, differences in error rate become particularly substantial as fragments get longer.
High-Q Strings DNA Fragments reduce the required screening effort by at least 60% compared to competitor products, and enable direct assembly of 5 kb constructs with reasonable screening effort (Figure 2).
Figure 2. Number of clones required to choose the correct one using 3 different error rates. The impact of a lower error rate is shown as the insert length increases.
Cost saving
GeneArt High-Q Strings DNA Fragments significantly reduce required screening effort and associated costs, and result in overall cost savings of more than 30%.
| Supplier 1 | GeneArt High-Q Strings DNA Fragments | |
|---|---|---|
| 1000 bp | ||
| Screening and sequencing cost | $39.00 | $16.50 |
| DNA fragment cost | $149.00 | $114.00 |
| Total cost | $188.00 | $130.50 |
| Additional total cost over High-Q Strings | $57.50 | |
| % cost savings vs. Competitor | 30% |
Screening and sequencing costs were calculated from the number of clones required for the identification of a correct clone with the following assumptions: 90% of clones contain an insert of expected size; associated costs of $1.50 per colony PCR reaction and $3.00 per sequencing reaction; 1000 bp inserts require 2 sequencing reactions, 1500 bp and 2000 bp inserts require 4 sequencing reactions.
GeneArt Strings DNA Fragments are custom-made, uncloned, double-stranded linear DNA fragments from 200 base pairs (bp) to 3,000 bp in length, assembled from synthetic oligonucleotides using the same high-quality process developed for Invitrogen GeneArt Gene Synthesis. Strings DNA Fragments are delivered dried, ready for resuspension, cloning, and screening to enable the identification of the correct clone.
All GeneArt Strings DNA products can be designed, optimized for protein expression, and ordered within our online order portal for delivery in tube format.
- Affordable—cost-effective alternative to GeneArt Gene Synthesis or Combinatorial Libraries
- Flexible—full gene design and cloning flexibility; enter your sequence and directly edit, optimize, and order through our online portal
- Fast—production time starts at 5 business days
GeneArt Strings Assistant
With GeneArt Strings DNA Fragments, your custom gene sequence may occasionally not fit our production criteria due to regions of sequence complexity. To mitigate this, we have launched the online GeneArt Strings Assistant app within Thermo Fisher Cloud.
After uploading, your DNA sequences area analyzed and potential problems are identified. You can then manually edit the sequences or you can use the suggestions offered by the Assistant which includes the introduction of silent mutations.
Edited sequences can then be ordered as GeneArt Strings DNA Fragments.
On this page:
Complete usage instructions can be found in the GeneArt Strings product bulletin. Choose the PDF based on your location:
| Product | Production time (business days)* |
List Price | Price per bp |
|---|---|---|---|
| DNA Fragments 200–600 bp | 3-5 |
$99 | **As low as $0.15/bp USD for a 1 kb DNA fragment |
| DNA Fragments 601–750 bp | 3-5 |
$129 | |
| DNA Fragments 751–1,000 bp | 3-5 |
$149** | |
| DNA Fragments 1,001–1,250 bp | 4-6 | $219 | |
| DNA Fragments 1,251–1,500 bp | 4-6 | $259 | |
| DNA Fragments 1,501–1,750 bp | 4-6 | $299 | |
| DNA Fragments 1,751–2,000 bp | 4-6 | $349 | |
| DNA Fragments 2,001–2,250 bp | 6-8 | $399 | |
| DNA Fragments 2,251–2,500 bp | 6-8 | $449 | |
| DNA Fragments 2,501–2,750 bp | 6-8 | $499 | |
| DNA Fragments 2,751–3000 bp | 6-8 | $549 | |
| DNA Libraries: IUPAC ntd | 10-15 | $49 per ntd |
*Production time is the number of business days required to synthesize GeneArt Strings DNA products in our manufacturing facility. Delivery time is in addition to production time and depends on the destination of the shipment.
Strings DNA products are suspended in 10 mM Tris pH 8.5 buffer and delivered dried, ready for resuspension and cloning. We recommend that you centrifuge tubes prior to opening, add the appropriate amount of water to the bottom of the tube, and incubate at least 1 hour at room temperature (alternatively incubate at 4°C overnight). After incubation, carefully resuspend Strings DNA products and use immediately. If not used immediately, resuspended Strings DNA products should be aliquoted and frozen at –20°C. Please avoid freeze-thaw cycles.
Delivery amounts:
GeneArt Strings DNA Fragments: ≥ 200 ng
GeneArt Strings DNA Libraries: ≥ 500 ng
Figure 1 shows an image of nine Strings DNA Fragments and five Strings DNA Libraries resuspended and separated using agarose gel electrophoresis .
Figure 1. Strings DNA Fragments (lanes 1-4 and 6-10) and Strings DNA Libraries (lanes 12-16) after gel electrophoresis (1% agarose gel). Library 1 is 501 bp; Library 2 is 649 bp; Library 3 is 998 bp; Library 4 is 404 bp; and Library 5 is 1989 bp. DNA marker is 1 kb DNA Ladder.
The GeneArt production team performs a biosecurity screen on each sequence entered. In the event your order does not pass this analysis, you will be contacted to determine the best way to proceed.
Strings DNA products can be cloned using any available cloning method, just make sure to design the ends of your sequence according to the respective requirements. You can simply paste the sequence into the online order form of the web portal and proceed to the cart to order. Alternatively, you can use the convenient GeneArt portal sequence editing and optimization functions. Depending on your desired cloning system, you may need to modify the 5′ and 3′ ends of your sequence to enable proper insertion into your desired vector. For example, for cloning Strings DNA products by restriction enzymes/ligation, we generally recommend adding additional stuffer nucleotides to both ends of your sequence to ensure efficient enzyme binding. If blunt cloning methods are used (e.g., Invitrogen TOPO technology), we recommend that you add 5–10 nucleotides of random stuffer DNA on both ends of the fragment, preserving functional DNA elements needed for downstream applications (by their very nature, linear DNA fragments are not entirely free of small terminal truncations).
Table 1. Examples for cloning methods and recommended sequence design.
| Restriction enzyme cloning | Add desired 5′ and 3′ restriction enzyme sequences, plus stuffer nucleotides |
| GeneArt Type IIs Assembly | Add desired 5′ and 3′ restriction enzyme sequences, plus stuffer nucleotides |
| Invitrogen GeneArt Seamless Cloning and Assembly | Add 15 bp sequence overlap (or more, depending on the kit) to vector or adjacent insert |
| Invitrogen Gateway Cloning | Add attB sites to enable proper recombination into Invitrogen pDONR vector |
| Invitrogen Zero Blunt TOPO PCR Cloning | Strings Fragments are blunt ended, so 5–10 stuffer nucleotides are recommended to compensate for small terminal truncations |
| TA and Invitrogen TOPO TA Cloning | Strings Fragments are blunt-ended and need to be adenylated using a Taq polymerase in the presence of dATP to add end-terminal A-overhangs |
Strings DNA Fragments are PCR amplicons of assembled oligonucleotides, ready for screening to identify the correct clone. Strings DNA Fragments are bulk sequence-controlled as part of the QC process to help ensure that your desired sequence is present in the fragment pool. To identify a correct clone >90% of the time, we recommend to use the screening guidelines in Table 2.
Table 2. Recommended screening of Strings DNA Fragments.
| Strings DNA Fragments up to 1 kb | Sequence 2 to 4 full-length clones |
| Strings DNA Fragments 1–2 kb | Sequence 3 to 5 full-length clones |
| Strings DNA Fragments 2–3 kb | Sequence 4 to 8 full-length clones |
Screening recommendations and application examples
Restriction enzyme cloning example with GeneArt Strings DNA Libraries
All 5 libraries were cloned by restriction digest, ligation and transformation of E. coli by electroporation. Resulting colony forming units (cfu) were counted and a value for the cloning of 500 ng library was extrapolated (blue bars). Colony-PCR was performed on 16 colonies each and the cloning efficiency calculated as the percentage of colonies with an insert of expected size (red bars). Error bars indicate standard error of the mean from multiple experiments.
GeneArt Seamless Cloning and Assembly example with Strings DNA Libraries
All 5 libraries were cloned using the GeneArt Seamless Cloning and Assembly Kit with subsequent heat shock transformation of E. coli. Resulting colony forming units (cfu) were counted and a value for the cloning of 500 ng library was extrapolated (blue bars). Colony-PCR was performed on 16 colonies each and the cloning efficiency calculated as the percentage of colonies with an insert of expected size (red bars). Error bars indicate standard error of the mean from multiple experiments.
GeneArt Type IIs Assembly example with Strings DNA Libraries
All 5 libraries were cloned using the GeneArt Type IIs Assembly Kit AarI with subsequent transformation of E. coli by electroporation. Resulting colony forming units (cfu) were counted and a value for the cloning of 500 ng library was extrapolated (blue bars). Colony-PCR was performed on 16 colonies each and the cloning efficiency calculated as the percentage of colonies with an insert of expected size (red bars). Error bars indicate standard error of the mean from multiple experiments.
Restriction enzyme cloning example with GeneArt Strings DNA Fragments
Eight Strings DNA Fragments up to 3,000 bp were cloned using 5’ AscI and 3’ PacI restriction enzymes. After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Eight (<1 kb) or 16 (>1 kb) colonies were picked, and colony PCR was performed to identify full-length clones; four to eight full-length clones were sequenced to determine the number of sequence-correct clones.
GeneArt Type IIs Assembly example with multiple Strings DNA Fragments
Eight Strings DNA Fragments of different lengths up to 2,800 bp with suitable sequence ends (AarI recognition sequence and 6 bp stuffer nucleotides) were used for direct assembly with the GeneArt Type IIs Assembly Kit Aar I (Cat. No. A15916). The resulting four genes were 5,056 bp, 5,061 bp, 5,267 bp, and 5,448 bp long. After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Sixteen colonies were picked and colony PCR was performed to identify full-length clones. For all four assembled genes, eight colonies were sequenced to determine the number of sequence-correct clones.
GeneArt Seamless Cloning example with GeneArt Strings DNA Fragments
Ten Strings DNA Fragments up to 3,000 bp were cloned using the GeneArt Seamless Cloning and Assembly Kit (Cat. No. A13288). After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Eight (<1 kb) or 16 (>1 kb) colonies were picked, and colony PCR was performed to identify full-length clones; four to eight full-length clones were sequenced to determine the number of sequence-correct clones.
GeneArt Seamless Assembly example with multiple Strings Fragments
Strings DNA Fragments are offered in lengths up to 3,000 bp. However, GeneArt Seamless assembly technology can be used to directly assemble two Strings DNA Fragments up to 1 kb without pre-cloning of the subfragments. If you want to assemble more Strings DNA Fragments or longer Strings DNA Fragments using seamless assembly technology, we generally recommend pre-cloning of the subfragments to limit the screening effort needed to find the correct clone after assembly. Alternatively, you can use GeneArt Type IIs assembly technology.
Twelve Strings DNA fragments of different lengths up to 1 kb with suitable sequence ends (15 bp homology to the vector or to the next fragment) were used for direct assembly with the GeneArt Seamless Cloning and Assembly Kit (Cat. No. A13288). The resulting six genes were 1,375 bp, 1,466 bp, 1,536 bp, 1,590 bp, 1,647 bp, and 1,853 bp long. After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Sixteen colonies were picked, and colony PCR was performed to identify full-length clones. For all six assembled genes, six colonies were sequenced to determine the number of sequence-correct clones.
Gateway cloning example with GeneArt Strings DNA Fragments
Five Strings DNA Fragments up to 1,000 bp with attB sites were cloned into pDONR 221. After ligation and transformation, bacteria were plated and incubated overnight at 37°C. Eight colonies were picked, and colony PCR was performed to identify full-length clones; four to seven full-length clones were sequenced to determine the number of sequence-correct clones.
The figure shows the percentage of clones with correct length as identified by colony PCR (cloning efficiency) and the percent of sequence-correct clones (fidelity) based on the number of full-length clones.
GeneArt Strings DNA Libraries
GeneArt Strings DNA Libraries are pools of GeneArt Strings DNA Fragments from 200–2000 bp, containing up to 3 blocks of degenerate nucleotides with randomized distribution. Each block can consist of up to 30 bp using the full IUPAC code of DNA nucleotides (U is not optional). Blocks need to be separated by 30 bp of non-degenerate nucleotides.
How to order
| NEW Option 1 GeneArt Strings Assistant |
Option 2 GeneArt Portal |
Option 3 Send Excel submission form to geneartsupport@thermofisher.com |
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| Detect and revise sequence complexities | |||
| Quick quote and ordering | |||
| Optimize sequences for protein expression | |||
| Order Strings DNA Libraries |
GeneArt Strings DNA Fragments are custom-made, uncloned, double-stranded linear DNA fragments, available in lengths from 200 base pairs (bp) to 3,000, assembled from synthetic oligonucleotides using the same process developed for GeneArt high-quality gene synthesis. Strings Fragments can be used to quickly clone your gene of interest. At least 200 ng of Strings DNA Fragments are produced within 5 (up to 1,000 bp) or 8 (from 1,000 to 3,000 bp) business days. GeneArt Strings DNA Fragments can be designed, sequence optimized, and ordered online and are a cost-effective and smart alternative to clone your expression plasmid.
While we used to offer Strings DNA Fragments between 100 – 150 bp, this is unfortunately no longer possible.
Strings Fragments are amplicons (PCR amplificates) of assembled oligonucleotides; an intermediate product of the gene synthesis production process. This process results in a pool of fragments, and cloning and screening need to be carried out to identify the correct clone. To ensure that correct fragments are present in the pool, Strings Fragments are bulk sequence-controlled before shipment.
Strings DNA Fragments are shipped dried, ready for resuspension and cloning. Before using, we recommend that you spin down the tube contents, add some water to the bottom of the tube to get the desired concentration, and let it incubate for at least 1 hour at room temperature (alternatively incubate at 4°C overnight). Subsequently, resuspend carefully and use immediately. For longer storage, resuspended Strings DNA Fragments should be dispensed into aliquots and frozen at –20°C. Please avoid freeze-thaw cycles.
No. Strings DNA Fragments from 200 to 1,000 bp are produced in 5 business days and Strings DNA Fragments from 1,000 to 3,000 bp are produced in 8 business days. Depending on the nature of the sequence, production time can vary.
Yes. Since you need to perform the cloning to obtain your final gene, Strings DNA Fragments prices are always below those for gene synthesis.
Yes. We recommend using the GeneArt web order portal for ordering, where you can use the free gene editing and optimization functions to adjust the sequence to meet your needs. After editing and optimization, please check again that the final sequences of the fragment(s) are exactly as needed for further processing in your lab (e.g., potential homologous overlaps of the fragments or restriction sites and buffer bases needed for cloning).
No, subcloning and assembly services are not available for Strings DNA Fragments, as they are designed to offer you the fastest and most affordable way to get access to your genes. If you do not want to clone your gene yourself, we recommend that you order full gene synthesis service.
Yes, we offer GeneArt Strings DNA Libraries from 200 – 2000 bp, containing up to 3 blocks of degenerate nucleotides. Each block can consist of up to 30 bp using the full IUPAC code of DNA nucleotides. Blocks need to be separated by 30 bp of non-degenerate nucleotides.
Yes, it is possible to directly assemble 2 Strings Fragments without pre-cloning. Thermo Fisher Scientific offers several technologies for seamless assembly, e.g., GeneArt Type IIs Assembly or GeneArt Seamless Cloning and Assembly. Please refer to the application examples section on this page for more information. Depending on the sequence length and the number of subfragments you want to assemble, the screening effort to find a correct clone can be high. We therefore generally recommend pre-cloning the subfragments to limit the screening effort required to find a correct clone after assembly.
No. Strings DNA Fragments are limited to 200 to 3,000 bp. If your sequence is longer, you need to order it as gene synthesis or assemble your gene from two or more Strings DNA Fragments. In addition, the Strings DNA Fragments manufacturing process is streamlined to very quickly and cost-effectively provide you with your gene product. If your sequence is complex, you may receive a message that it cannot be produced as a Strings DNA Fragment due to high complexity. In that case, we recommend modifying your sequence to match the production criteria (given below) or ordering your gene as gene synthesis. In many cases, optimizing your sequence using the portal function enables manufacturing with the Strings Fragments process. If it is still not able to be produced, you can manually edit the sequence to enable production.
Important production criteria are:
- GC content between 20% to 80% (in peaks, not overall content)
- No long secondary structures or sequence repetitions
- No A/T stretches >25 bp nor G/C stretches >20 bp
Please refer to the section near the top of the page: "Screening Recommendations & Application Examples".
| Classical PCR & cloning | Synthetic DNA fragments | Gene synthesis | |
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| How we can help you | GeneArt Strings DNA Fragments | GeneArt Gene Synthesis and Subcloning Service | |
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| Labwork | High | Medium | Low |
| Production time* | NA |
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*Production time is the number of business days required to synthesize GeneArt Strings DNA Fragments in our manufacturing facility. Delivery time is in addition to production time and depends on the destination of the shipment.
Options for DNA Libraries
| GeneArt Strings DNA Libraries | GeneArt Combinatorial Libraries | GeneArt Combinatorial Libraries with Next-generation sequencing | |
|---|---|---|---|
| Design flexibility | + Full IUPAC code available; however limited control over occurring amino acids |
+++ TRIM technology allows for the accurate determination of occurring amino acids and ratios |
+++ TRIM technology allows for the accurate determination of occurring amino acids and ratios |
| Correctness | + Gene synthesis process used, more unintended mutations occur |
+++ Error free template provides best possible correctness results |
+++ Error free template provides best possible correctness results |
| Cost | + | ++ | +++ |
| Production time | +++ 10-15 business days | + 4-6 weeks | + 4-6 weeks |
The research leading to results regarding GeneArt Strings DNA Libraries has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement nr. 613931.
For Research Use Only. Not for use in diagnostic procedures.
