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Transgenic Mouse Core Facility

Mouse Genotyping Service

Mouse genotyping is defined in this Transgenic Mouse Care Facility as a procedure that identifies genetically-engineered mice having foreign DNA fragments stably integrated into their genome. As a result of foreign DNA integration, mice may over-express some proteins of interest (transgenic) or have an endogenous gene disrupted (knockout) or may express a gene of interest in a specified locus to replace an endogenous gene (knockin). The procedures for confirming these genomic changes include Southern blotting, polymerase chain reaction (PCR) or others.

The most common is PCR-based genotyping that uses a few DNA primers to specifically amplify foreign DNA and/or endogenous genomic DNA from mouse tissue DNA samples in test tubes. A tiny amount of mouse tail, toe, or ear tissues is used for DNA extraction. PCR products are separated on agarose gels by electrophoresis and visualized under UV light.

Genetically-engineered mouse models have been widely used in biomedical research for studying function and interaction of genes. Additionally, many animal models for human diseases have been created by transgenic technology. These models are invaluable for the study of mechanisms underlying human diseases and for the screening of drugs treating these diseases. However, all studies are dependent on correct genotyping of these animals, which can be frustrating, time-consuming and costly.

The Transgenic Mouse Core will provide a mouse genotyping service on a fee-for-service basis using PCR. This service is designed for investigators who do not have sufficient ongoing need to set up this capability in their own lab. Investigators with large numbers of animals and with an ongoing need for genotyping, likely will find it more economical to set up to do genotyping in their own lab.

Services Provided
  1. The Core director will provide consultation in PCR-based genotyping including primer design and optimization of PCR conditions.
  2. Staff in the Transgenic Mouse Core will perform DNA extraction and PCR using tissue samples and primers provided by the investigator. After initial setup and testing of PCR conditions, genotyping results will be emailed to investigators within one week post delivery of tissue samples.
  3. The Core cannot guarantee the genotyping result is 100% correct since the Core cannot control for cross-contamination of tissues during tail snip (see below for caution in tail snip).
Scheduling Requirements
  • Services cannot be scheduled until all project criteria described below are met, and a Mouse Genotyping Request Form is approved.
  • Before mouse genotyping services can be initiated, investigators must consult with the Core Director, Dr. Liqing Yu, for primer design and optimization of PCR conditions if they do not have a reliable PCR protocol for their mouse lines.
  • If investigators have reliable PCR protocols that work in their laboratory and they want the Transgenic Mouse Core to help with their routine genotyping, evidence in support of PCR reliability must be provided, such as a detailed protocol and gel images.
  • Primers need be newly ordered without any dilution.
  • Tail tip is the preferred tissue for DNA extraction. A 3-mm segment of tail tip is ideal. Please collect tail tips in ice-cold 1.5-ml Eppendorf tubes and either immediately deliver them on ice to the Transgenic Mouse Core Staff, to the attention of Dr. Feng Guo, or freeze them at -20°C for a convenient later delivery. Since PCR-based genotyping is very sensitive, and a tiny amount of tissue contamination will cause a false positive result, it is critical that scissors or razors be thoroughly washed using plenty of water and wiped-dry between each tail snip with ethanol, to avoid potential cross-contamination.
  • No cancellation is allowed for this service once tail tips have been delivered to the Core lab, since tissues will be processed immediately upon delivery.
  • If the investigator wishes to re-check DNA from a mouse, an additional tail snip should be taken. Due to the potential for cross-contamination, re-analysis of processed DNA is not recommended.
Fees:
  1. A one-time $500 setup fee will be charged if there is no established PCR protocol for genotyping this mouse line, and the Core has to work out the conditions.
  2. A one-time $100 setup fee will be charged if there is an established PCR protocol that has been shown by the investigator to work in his or her lab.
  3. A fee of $10 per tail clip will be charged.