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Concept: To accelerate the ability to transfer a transgene or knock-out region onto different genetic backgrounds. Microsatellite marker analysis at each generation will be used in order to generate a congenic strain on a desired genetic background in five generations.
Recommended Breeding Scheme:
- Mate animals (donor) containing genetic region of interest (transgene, knock-out gene, etc.) to animals of recipient strain to produce the F1 generation. Recipient animals must be inbred and homozygous at the locus of interest. All F1 animals will be 100% heterozygous at every locus.
- Mate F1 animals to animals of recipient strain. We do not use genetic markers on the X or Y chromosomes in our assay therefore it is recommended that the sex chromosomes be fixed early in the breeding scheme for convenience. Mate female F1 animals to male recipient strain animals to fix the Y and generate the N2 generation.
- Analyze the DNA from 8-10 males who carry the genetic region of interest by microsatellite analysis. We offer genotyping services for performing or developing gene-specific PCR assays to genotype for the genetic region of interest or the client can perform the genotyping prior to sending tail snips for microsatellite analysis.
- Based on the microsatellite analysis, you choose 2-4 animals that have the greatest percentage of recipient genome and mate these to female recipient strain animals. This will generate the N3 generation and fix the X chromosome in the males.
- Analyze the DNA from 8-10 males with the genetic region of interest from the N3 generation by microsatellite analysis. Choose the 2-4 males that have the greatest percentage of recipient genome. Continue this selected breeding backcross process through the N5 generation. At this point, >99% of the genome should be derived from the recipient genetic background.
Sample Submission:
- Tail snips are required. Send 3-5 mm of tail per animal in individual microfuge tubes labeled with the animal ID number.
- Samples should be shipped overnight on ice packs. If samples will take longer than overnight to arrive or the air temperature is greater than 85 degrees, please ship samples on dry ice.
- Fill out the Speed Congenic Submission form and include with samples. Please fax form to (573-884-7521) or submit on-line submission form prior to shipment.
Microsatellite Analysis:
- DNA extraction will be performed on samples.
- The DNA will be analyzed using a low density number of, typically 65, microsatellite markers - 3 markers per chromosome with an average genetic distance between markers of 20 centiMorgans. The sex chromosomes are not assayed. For additional information see, Immunol Today. 1997 Oct;18(10):472-7., Nat Genet. 1997 Nov;17(3):280-4., and Comp Med. 2005 Feb;55(1):34-6.
Analysis Results:
- Results will be available within 7-10 business days following receipt of samples.
- The report will include the number of markers that tested as homozygous recipient, the number of markers that tested as heterozygous and the estimated % of the genome that is homozygous for recipient alleles for each animal. This will allow you to choose the animals that have the greatest percentage of fixed homozygous recipient alleles to use for breeding to produce the next generation.
- You will be notified by email when the analysis is complete at which time you will be able to access the report on-line at www.radil.missouri.edu.
- A copy of the report will be sent upon completion of the testing.
For questions or additional information regarding Speed Congenic Services and/or sample submission please contact the RADIL at radil@missouri.edu or phone 800-669-0825.