You know you want to! Go ahead, see if you can ...

The ability to roll your tongue is caused by a dominant gene (R). If you can't roll your tongue, you are a non-roller and must be homozygous recessive (rr).

A father cannot roll his tongue but a mother can. Of their four children, one daughter cannot roll her tongue. The other daughter and both sons can roll their tongues.

1. What percent of the offspring are homozygous non-rollers?
   

     



2. What percent of the offspring are heterozygous rollers?
   

     



3. Can the parents produce a homozygous dominant child?
   

     



4. How could the cross for the parents (father x mother) be written using the "dash" technique for unknown genes?