Frequently Asked Questions
Frequently asked questions about cDNA cloning, subcloning, PCR cloning, and delivery
What is cDNA cloning, and how does it differ from gene synthesis?
cDNA cloning starts from an existing cDNA template, usually from a cDNA library or ready-to-use plasmid library, and obtains the target-gene fragment by PCR amplification or restriction digestion before cloning it into a vector.
Gene synthesis requires no template and chemically constructs the complete gene sequence de novo from oligonucleotides.
cDNA cloning is less expensive and faster but depends on template availability. Gene synthesis offers greater flexibility, including codon optimization and sequence customization, and is suitable when no template is available or sequence changes are required.
What is the difference between subcloning and PCR cloning, and which should I choose?
Subcloning transfers a target-gene fragment from an existing plasmid into a new vector after restriction digestion. It is suitable when the gene is already present in a plasmid and only the vector needs to be changed.
PCR cloning uses cDNA, genomic DNA, or plasmid DNA as a template and amplifies the target fragment with PCR primers before cloning it into a vector. It is suitable for directly obtaining genes from biological samples or adding specific restriction sites.
If your gene is already available in our ready-to-use library, subcloning is the fastest and most economical option. If the gene must be cloned from your sample, choose PCR cloning.
Can you clone a gene into a vector that I provide?
Yes. We can clone a target gene into any commercial or customer-provided vector. For customer-provided vectors, supply the vector map, sequence information, and sequencing-verification results, or provide the physical vector for sequencing verification. Uncommon restriction enzymes may be supplied by the customer or purchased on the customer's behalf; the customer covers the cost and any remaining enzyme is returned.
What is the purity of the delivered plasmid DNA, and can it be used directly for transfection?
Standard plasmid DNA has an A260/A280 ratio of 1.8–2.0 and is suitable for most molecular-biology procedures, including restriction digestion, PCR, and sequencing. For direct cell transfection, especially with sensitive primary or stem cells, we recommend the endotoxin-free plasmid-preparation add-on, which controls endotoxin below 0.1 EU/μg for improved transfection performance.
What happens if sequencing reveals a sequence error?
We provide sequence-accuracy assurance for all delivered cDNA clones. If our operations cause a discrepancy from the reference sequence, we will resynthesize or reclone the construct at no charge until the sequence is correct. If the difference results from a natural variation in the PCR template, such as an SNP, it will be documented in the delivery files and confirmed with you.
Can genes larger than 5 kb be cloned, and how long does it take?
Yes. Genes larger than 5 kb are considered complex projects. We evaluate sequence complexity, including GC content, repeats, and secondary structure, and provide a customized plan and quotation. For large genes, gene synthesis without a template or homologous recombination from large-fragment vectors such as BAC/PAC is often recommended. Contact technical support for a timeline assessment.
Which species are covered by your cDNA templates?
The ready-to-use template library covers cDNA from human, mouse, rat, rabbit, cynomolgus/rhesus macaque, canine, ferret, zebrafish, and other species. It also includes genes from nearly 40 viruses, including influenza viruses with 60 subtypes and 160 strains such as H7N9 and H5N1, as well as MERS-CoV, HCV, RSV, and HCoV. Genes not included in the library can be obtained through PCR cloning or gene synthesis.
How can I check whether a gene is available in the ready-to-use library?
You can search in the following ways:
(1) Enter the gene name, NCBI Gene ID, or Accession Number in the website search box;
(2) Contact technical support by email or phone and provide the gene information for assistance with the search.
