11 ms·

I'm guessing GP is referring to the fact that most popular mouse strains for research are, in theory, isogenic (genetically identical). This is achieved by inbr

by ghkbrew 10y ago

I'm guessing GP is referring to the fact that most popular mouse strains for research are, in theory, isogenic (genetically identical). This is achieved by inbreeding the mice for multiple generations until they are statistically certain to be homozygous at every gene locus. The standard is 20 generations. Thus making all the mice in a strain as close genetically as clones or twins There are of course issues with random mutation. So the mice end up not being _exactly_ identical. JAX actually puts a lot of effort into trying maintain the genetic stability of their strains through methods such as freezing founder sperm and rebreeding it into later generations.

jessriedel 10y ago
Naive question: do the clones have to have all genes for recessive disorders eliminated so they can interbreed without risk? If so, how did they get that?
- ars 10y ago
  They probably simply killed the ones with [noticeable] problems.
- ghkbrew 10y ago
  I've never done it, but I think those are just naturally bred out by breeding healthy mice from each successive generation.
  - Someone 10y ago
    Many of the strains they sell aren't healthy. If you enter a condition or disease like 'lung cancer' or 'paralysis' in https://www.jax.org/mouse-search https://www.jax.org/mouse-search, you'll find they sell a mouse that's susceptible to a form of it. For example, https://www.jax.org/strain/004863 https://www.jax.org/strain/004863: "Homozygous Snap25 knock-out mice exhibit neonatal lethality. Late embryos lack spontaneous movement or sensorimotor reflexes, and abnormal innervation and muscle fiber development is observed." Breeding mice that die at birth is an unsolved problem I'm sure they are thinking of, so they sell the heterozygous variant (carriers of the gene)
    - ralfd 10y ago
      > Breeding mice that die at birth is an unsolved problem I'm sure they are thinking of That sentence is both horrible, absurde, macabre and logical at the same time.

by ghkbrew 10y ago

jessriedel 10y ago

Naive question: do the clones have to have all genes for recessive disorders eliminated so they can interbreed without risk? If so, how did they get that?

ars 10y ago
They probably simply killed the ones with [noticeable] problems.
ghkbrew 10y ago
I've never done it, but I think those are just naturally bred out by breeding healthy mice from each successive generation.
- Someone 10y ago
  Many of the strains they sell aren't healthy. If you enter a condition or disease like 'lung cancer' or 'paralysis' in https://www.jax.org/mouse-search https://www.jax.org/mouse-search, you'll find they sell a mouse that's susceptible to a form of it. For example, https://www.jax.org/strain/004863 https://www.jax.org/strain/004863: "Homozygous Snap25 knock-out mice exhibit neonatal lethality. Late embryos lack spontaneous movement or sensorimotor reflexes, and abnormal innervation and muscle fiber development is observed." Breeding mice that die at birth is an unsolved problem I'm sure they are thinking of, so they sell the heterozygous variant (carriers of the gene)
  - ralfd 10y ago
    > Breeding mice that die at birth is an unsolved problem I'm sure they are thinking of That sentence is both horrible, absurde, macabre and logical at the same time.