Marker Retention service, also known as Plasmid Loss analysis service, is offered to determine the percentage of cells in a cell  sample that contains a selectable marker such as antibiotic resistant gene. In microbial cell culture process, a bacteria stain may lose its antibiotic resistance due to the loss of its resistant-coding plasmid, an undesirable event in biologics manufacturing.

Test sample will be tested for the presence or absence of the selective marker, such as an antibiotic resistant gene coded in the plasmid in E. Coli. Test sample, positive, and negative cells will be plated to obtain isolated colonies. Results will be reported as the percentage of cells retaining the marker, or percentage of plasmid loss.

A report with the following information will be delivered: images of selective and non-selective growth plates, colony counts, and calculation of percentage of marker retention or plasmid loss.

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GLP/GMP Compliant
Genomics & Biological Services

  • Experienced scientists functioning as project managers or study directors

  • Independent quality unit assuring regulatory compliance

  • Methods validated per ICH GLP/GMP guidelines – also research grade testing available

  • Rigorous sample tracking and handling procedures to prevent mistakes and cross-contamination

  • Controlled laboratory environment to prevent cross-contamination

When you partner with Avance Biosciences™, you gain a CRO partner that is creative, collaborative and dedicated to sound science with a focus on the regulatory requirements our partners require. Contact our technical staff to discuss how we can support you in your project!


Dedication to Quality

Dedication To Quality

The Avance Biosciences™ team is committed to strict adherence to CGMP and GLP regulations enacted by the US, European, Japanese, and other international regulatory agencies.


Extensive Experience

Open Communication

Our team has extensive knowledge and experience working with scientists, QA/QC professionals, and project managers from over 100 pharmaceutical and biotechnology companies and organizations throughout the world.


Open Communication

Open Communication

Transparency and integrity are two of our core values. Our well-trained, friendly, and professional study directors and project managers strive to complete your projects on-time with open communication channels and to your specifications.


Cutting Edge Science

Open Communication

Avance Biosciences™’ CGMP/GLP compliant genomic and microbial assays make use of the advanced technologies including real-time PCR, ddPCR, Sanger sequencing, next-gen sequencing, Southern blot, and more.