Speed Congenics FAQs

What is Speed Congenics?
PolyGenes speed congenic service is your fastest choice to obtain a congenic line.
This service is for you either

  • If you have a genetically modified mouse (donor) on a mixed or undefined background
  • or

  • If the original background is not suitable for particular analysis of the phenotype and you have to backcross your gene of interest onto another strain (recipient).
  • We screen the genetic background by tetranucleotide microsatellite marker analysis, defining those animals with the highest percentage of the desired background, which will be further used for breeding.

    For which mouse strain pairs does PolyGene offer Speed Congenics?
    We offer 5 sets able to differentiate the following two mouse strains: B6 versus 129, B6 versus FVB, B6 vs Balb/c, B6 vs DBA/2 and B6 vs NOD.
    What if PolyGene doesn’t have markers for the mouse strain I need?
    PolyGene’s customizable solutions enable us to develop markers for your specific mouse strain within 3-8 weeks based on our database of 700 possible tetranucleotide microsatellite markers. This enables a faster and less expensive screening. Please contact info (at) polygene (dot) ch for more information.
    Do I need to know the background of the strain?
    Yes, it is necessary to know the background of your mouse strains. It is also important to send the pure strains of your facility, because we made the experience that every lab could have its own substrains.
    Why is the genetic background information of a mouse strain important?
    To ensure that whatever effect seen in a genetically modified mouse is not due to background variation, but is more likely the result of a specific genetic modification.
    What is the average distance between the 96 microsatellite markers?
    The 96 microsatellite markers lay evenly dispersed on the 19 autosomal chromosomes. On each chromosomes, 5 markers are positioned, except for the larger chromosome 1 with 6 markers. The distance between the markers are on average 10-20 cM or 20-40 Mb, respectively, depending on the size of the chromosome and the number of intervening chromosomal crossovers.
    How quickly will I receive the results of the analysis from the first generation?
    You will receive the results within 3-6 business days after PolyGene obtains the mouse tail biopsies.
    How do I send PolyGene the mouse tissue?
    The tail biopsy, 0.4-0.6 cm in length, should be send in 70 % ethanol in a tube sealed with parafilm or with a screw cap. The tubes should be shipped in a bubble wrap or padded envelope. We prefer to receive the samples within 1-4 days.
    Which animals should be tested?
    Only those animals should be genotyped that are carrying the gene of interest. We do not test the animals of the F1 generation, because they have one allele from each parent, so that they have 50% from each parental strain.
    Does PolyGene recommend a breeding scheme?
    Yes. Because we offer a set of 96 microsatellite markers evenly dispersed over the 19 autosomal chromosome, it is very important to follow our breeding scheme. Due to this breeding scheme, the sex chromosomes can simply be fixed by breeding rather than by selection.
    How many animals must be chosen for each generation of breeding?
    We recommend up to 3 breeding pairs for each generation just in case an animal is not able to breed. After the fixation of the sex chromosomes to the targeted genetic background, we normally tend to use modified male animals because of the faster production of offspring.
    What about SNPs versus microsatellite markers?
    A SNP marker (single nucleotide polymorphism) is a single base in a genomic sequence that occurs in two variations (e.g. A or G); a microsatellite of high quality has a variety of known alleles. This is why, for a random population (like the human population or an outbred animal strain), about four SNPs are necessary to obtain the same information than with one microsatellite.
    When comparing two inbred mouse strains, a SNP is just as informative as a microsatellite, but of course, only if it is a SNP indeed! In most arrays, established and proven SNPs for a larger population are used, and only a minority represents differences between your two given mouse strains examined. In our experience, from 388 established SNPs, less than 96 are informative. In Speed Congenics all 96 microsatellites are informative.
    Who do I contact for more information on the Speed Congenics Service?
    Stefan Selbert, PhD
    email: info (at) polygene (dot) ch
    phone: +41 44 818 88 03

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