- Mouse and Rat Microsatellite and SNP Genotyping Supporting Marker-Assisted Backcrossing (Speed Congenics)
- Genetic Background Characterization of Genetically Engineered Mouse Lines
- Genetic Quality Control of Inbred Strains
- Mouse and Rat Cell Line Characterization and Mycoplasma Testing
- PCR Testing for Rodent Infectious Agents
- H2 (MHC) Haplotyping and PCR Sex Determination
- Passenger Mutation Analysis (e.g., Crb1<rd8>; Nnt deletion, etc.)
- Rodent Genetic Consultation
Mouse and Rat Microsatellite and SNP Genotyping Supporting Marker-Assisted Backcrossing (Speed Congenics)
Transgenic and targeted mutants frequently need to be transferred to a more suitable inbred background for phenotypic analysis or crossed with cre-expressing lines crossed with floxed alleles. Traditional congenic strain development requires a series of backcrosses between the donor strain carrying the mutation (often on a mixed genetic background) and a recipient strain with a defined genetic background (typically an inbred strain) over many successive backcross and taking three years. Marker-assisted (speed congenic) protocols reduce this time from 10 backcross generations to five.
Genetic Background Characterization of Genetically Engineered Mouse Lines
Sharing mouse lines has become commonplace but the majority of these genetically modified lines are not well characterized in terms of genetic background and are referred to as having a “mixed background” (e.g., 129;B6). Genetic background can strongly influence phenotype, due to modifier genes, as is the case for Trp53 and Pten null mice. Our Background Strain Characterization service can provide estimates (percentage of alleles) of the inbred backgrounds implicated in your mouse or rat model.
Genetic Quality Control of Inbred Strains
The purpose of the genetic quality control is to monitor the authenticity of mouse and rat inbred strains. Genetic monitoring relies on both the use of molecular genotyping protocols and the observation of specific strain characteristics (like coat color). The ability to distinguish inbred strain backgrounds has greatly expanded with the development of microsatellite markers.
Mouse and Rat Cell Line Characterization and Mycoplasma Testing
Cross-contamination or misidentification of cell lines is a serious problem. It is estimated that 15-30% of human cell lines are misidentified or contaminated, with the consequent invalidation of published data and wasted time and money. Although information on contaminated rodent cell lines is scattered, it is expected to be widespread. LAGS offers SSLP (also known as STR) and SNP analysis for mouse and rat cell line characterization. Upon submission of DNA, we will generate an allelic profile using a standard panel of SSLPs or SNPs. In order to rule out contamination with human or rat cells, we will include human- and rat-specific SSLP primers. It is important to understand that the SSLP or SNP profile will only determine the inbred strain origin for the cell line (and rule out cross-contamination with other cell lines from a different strain or species), but will not identify a particular cell line. For example, examining DNA from a pure B16 melanoma cell line will show a C57BL/6 profile because this is the origin, but the profile will be similar for a LLC cell line, also established from C57BL/6. For ES cell lines characterization, we recommend our tailor-made Background Characterization service.
Contamination of cell cultures with Mycoplasma spp. is recognized as a very serious problem that can significantly impact data interpretation. LAGS uses the MycoAlert™ test from Lonza, a luminescence-based, bichemical test providing rapid screening for Mycoplasma contamination.
PCR Testing for Rodent Infectious Agents
We offer infectious diseases testing for the following agents: Syphacia obvelata and Aspiculuris tetraptera (pinworms), Myocoptes musculinus, Myobia musculi, and Radfordia affinis (fur mites) Helicobacter spp., Campylobacter spp., mouse parvovirus (MPV)*, rat parvovirus (RPV)*, mouse norovirus (MNV) and mouse hepatitis virus (MHV) and pinworms. Tests for other infectious agents can also be developed and implemented according to the specific needs of your animal colony.
Mouse H2 Haplotype and Sex Determination
We offer a PCR-based assay to determine the Major Histocompatibility Complex (H2) haplotype for your mice. This information can be useful for projects involving tissue grafts (e.g., hematopoietic) among genetically modified or mutant mice with undefined H2 haplotype, preventing graft rejection and graft-versus-host disease. We also offer a PCR assay for accurate sex determination in mice.
Passenger Mutation Analysis
Passenger mutations are mutations that are hidden in the genomes of substrains and potentially affect the outcome of an experiment. These mutations typically arise due to genetic drift among separate populations derived from the same original inbred strain, resulting in new and unique phenotypic characteristics. For example, mice of the C57BL/6N substrain (NIH) and not the C57BL/6J (JAX) are homozygous for a single nucleotide deletion of Crb1 (rd8 mutation), which will render these mice inadequate for behavioral studies requiring vision. Other examples include mutations in: Nnt, Skint1, Casp4, Gpr84, Patch1 (susceptibility to SCC), Pde6b (rd1), Bfsp2 (dundee), Gnat1 (IRD1/IRD2), Gnat2 (cpfl3), mt-Atp8<m1> (increased anxiety-like behavior), and Hc (complement C5). In the case of mixed or unknown backgrounds (particularly GEM lines), these mutations can produce unusual or unexpected results. LAGS offers specific genotypes for the mutations listed above.
Rodent Genetic Consultation
We also provide consultation in a variety of mouse and rat genetics topics. This includes standard inbred strain and gene nomenclature, selection of the appropriate inbred background, development of genetic crosses, linkage analysis for simple genetic traits, etc.
Fernando Benavides, D.V.M., Ph.D., DACLAM
Director, Laboratory Animal Genetic Services
Professor, Epigenetics and Molecular Carcinogenesis
The Virginia Harris Cockrell Cancer Research Center
at the University of Texas MD Anderson Cancer Center, Science Park, Department of Epigenetics and Molecular Carcinogenesis
Mailing Address: P.O. Box 389, Smithville, Texas 78957
Physical Address: 1808 Park Road 1C, Smithville, Texas 78957