Instructions
Overview
 
Problem 1: Tongue Rolling
Tongue Rolling
 
Problem 2: Eye Colour
Eye Colour
 
Problem 3: Diabetes
Diabetes
 
Problem 4: Blood Type
Blood Type
 
Quiz
Quiz
TONGUE ROLLING

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).

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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.
PEDIGREE




      
homozygous dominant male

    
heterozygous/carrier male

    
homozygous recessive male

    
homozygous dominant female

    
heterozygous/carrier female

    
homozygous recessive female

    
    
homozygous dominant genotype

    
    
heterozygous/carrier genotype

    
    
homozygous recessesive genotype

  
generations

QUESTIONS
  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?

      


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