Speed Congenics

A congenic strain is derived from the transfer of a genetic mutation or knockout region from one genetic background (donor strain) onto another genetic background (recipient strain).   It is developed when a donor strain, often having a mixed genetic background, is backcrossed repeatedly with a recipient strain having a defined genetic background (an inbred strain).  Traditionally, it requires a minimum of 10 backcross generations (approximately 3 years) to create a 99.9% congenic strain.  On the other hand, speed congenics—also known as marker-assisted breeding—selects progeny that contain the highest percentage of recipient genetic background for further backcrossing.  This speed congenics strategy shortens the backcrossing to 5 generations, allowing the development of congenic strains in approximately 1.5 years.

The VARI Speed Congenics Service provides a single-nucleotide-polymorphism (SNP) marker-assisted approach to generate congenic mouse strains.  High-throughput, high-density mouse SNP arrays from the Illumina BeadArray technology are used.  A total of 1,449 SNP loci that cover the top ten inbred strains are genotyped in either a 96-sample Sentrix Universal Array Matrix or a 16-sample Sentrix Universal BeadChip.  The ten inbred strains that the SNP array covers are C57BL/6J, 129S1/SvImJ, FVB/NJ, BALB/cJ, DBA/2J, NOD/LtJ, CBA/J, AKR/J, C3H/HeJ, and SJL/J.  The data is analyzed with the Illumina BeadStudio software.  Further analysis for each project involves the use of novel algorithms to determine the breeders having the highest recipient background for subsequent backcrossings.

The VARI Speed Congenics Service can reduce the genetic background effects and enhance the phenotype of a mouse model.  Assuming no problems with breeding or animal health, it also decreases the investigator’s time and expenses from 3 years to 1.5 years.  Overall, this service will provide the competitive edge for the investigator’s research.