Genotype chimeras? - (Feb/22/2014 )

Once you have injected your ES cells into blastocysts and got chimeric pups, do you bother genotyping the pups? I suppose it doesn't matter if they have the transgene/construct/KO in their tail (or blood or whatever you'd genotype), only in their germ cells...So do you just breed them and then see if you get trangenic pups (by coat color or genotyping) or genotype?

Thanks.

 Well how confident are you that your chimeras are actually chimeras? Do they have that patchy-fur chimeric look?

I'd probably take tissue samples from the F0's and keep them on ice just in case.