> that of the resulting pups, half of them will be
> carriers as well.

    This has been a good discussion, and I'm learning all the time (and
could use to, says my teenager  <snort>).
    Actually, the incidence of a trait showing up in 50% of the pups works
out if there are thousands of pups...most litters are smaller.  With a small
sample size litter of 3 to10, the probability of a pup being a carrier is a
coin flip and not much effected by percentages.  All could have it, or maybe
none have it.  You can easily get five heads in a row with that coin...

Rini
"They say I have ADD but they just don't under... HEY, A CHICKEN!"