Bil 150 Practice Genetics Problems:

1.  In squash the gene, W for white color, is dominant over its allele, w for yellow color.
           The expected F1 phenotype(s) from a cross between homozygous white
            and yellow squash would be ?

2.  In ALF's (Alien Life Forms) brown fur (B) is dominant to white fur (b). 
       
A brown furred ALF named Charly is crossed with a white furred ALF
        and the progeny occur in the ratio of 50% brown to 50% white.
                What is the likely genotype of Charly ? 

3.  Charly in the above question has a genotype that is ?
           
  a) homozygous dominant    b) homozygous recessive    c) heterozygous
              d) dihybrid                      e) unknown    

4. The ability to roll one's tongue into a U-shape is determined by the presence
         of a non-sex linked dominant gene, T.
  
             A man, unable to roll his tongue, and a woman able to roll hers, have four
                children. The woman's mother couldn't roll her tongue, but her father could.  
                Of their four children how many might you expect to unable to roll their tongues ?

5. A couple has four children whose blood types are A, B, and AB.
               Which of the following genotypes is capable of producing the blood types
                of this couples children ?

  
                    
a)  Ai and Bi       b)  Ai and BB        c)  Ai and ii         d)  Bi and ii        

6.   College World Series Omaha-itis is a sex-linked recessive disease
        of the species Ibis, which is quite often fatal.  Death, however, occurs
        only in the years of National Championships.  It has been determined that,
        by chance, Sebastian (the Hurricane Ibis male mascot) has the disease
        and mates with a female Ibis who is heterozygous for the disease. 
              A) if they have a single chick, what is the probability that it will have the disease,
        and  B) if Sebastian and his bride have a male chick, what is the probability
                    that he would have the disease

7.  A human recessive genetic disease, termed Charlyitis, is found on chromosome 12
        and is often fatal.  Suppose by chance that a boy, Michael, who has this disease
        lives past puberty and marries a normal woman, but whose father also had Charlyitis. 
  
     If this couple have any children what is the probability that the children
  
     will have Charlyitis ?