on mice mating - (Aug/20/2007 )

The mating between 129/sv and C57BL/6 mice will give the mice (F1) with
mixed background. The second mating between F1 will have black or brown. It
is possible to have mice with other colors, for example, white.
Recently, I got the mice with black, brown and also white. I think maybe the
animal caretakers made mistakes on my mice, or my ES cells are not from
pure backround.
Somebody have suggestions?
Thanks!

You could try to genotype them to be really sure. Charles River needs a tail snip and for a few $$ they'll do the whole thing for you.

try genotyping, thats the best way to differentiate the mice. I wouldnt rely entirely on the coat color.