Possible causes include:

• Unreasonable primer design

• Poor template quality

• Incorrect PCR program settings.

• Dual system compatibility: Shuttle vectors contain two or more replicons from different genetic backgrounds,enabling replication in two or more different organisms.

• Selective markers: Shuttle vectors usually contain selective markers, such as antibiotic resistance genes, allowing for easy screening of clones containing the target gene via antibiotic selection.

• Higher Efficiency: Shuttle vectors are typically more efficient when introduced into the target biological system.

Shuttle vectors are used in various fields, including:

• Gene function research

• Protein interaction analysis

• Drug target screening

• Vaccine development

The efficiency of shuttle vectors makes them suitable for various application, ranging from academic research to drug development,supporting scientists and researchers in their pursuit of research and innovation.