Name:____________________________________________Date: _______

bee icon Genetics Practice Problems - Easy Mode

guinea pig

1.  For each of the genotypes (letters)  listed, write a phenotype (description).   

In pea plants, purple flowers are dominant to white.

                PP  =  purple                Pp  = ____________________         pp =  _____________

                In guinea pigs, short hair is dominant to long hair.

                HH = _______________     Hh  = ________________     hh  = __________________

2.  In guinea pigs, black eyes are dominant to  red eyes.  Choose a letter combination for each phenotype.

______  = black eyes                      _______  = black eyes                    ________ = red eyes     

Level 1 (Easy Mode):   

Complete  the Punnett squares for each of the crosses for guinea pigs and eye color. Write answers as fractions.

3. Bb x bb

How many guinea pigs will have black eyes   _________                       red eyes  __________

4. bb x BB

How many guinea pigs will have black eyes   _________                       red eyes  __________

5. Bb x Bb

How many guinea pigs will have black eyes   _________                       red eyes  __________


Level 2 (Normal Mode):  

Setup and complete punnett squares for each of the crosses.

guinea pig

Reminder:  In guinea pigs, black eyes (BB, Bb) are dominant to red eyes (bb)
Short hair (HH, Hh) is dominant to long hair (hh)

6.   A guinea pig with long hair (hh)  is crossed with one that has short hair (H H). 
Set up the Punnett square below.

 

 

 

What percentage of the offspring  will have have short hair?    ______

7.   A guinea pig with long hair (hh)  is crossed with one that has short hair (H h). 
Set up the Punnett square below.

 

 

 

What percentage of the offspring  will have have short hair?    ______

7.   A guinea pig with black eyes  (B b)  is crossed with one that also has black eyes (B b). 
Set up the Punnett square below.

 

 

 

What percentage of the offspring  will have have black eyes?    ______         red eyes? ________


cat

Level 3 - Hard Mode

Heterozygous means that the individual has two different letters, for example Aa, Bb, Dd.  
Homozygous means that the individual has two same letters, for example  AA, bb, DD, eee

Cats can have a trait where their ear folds down, a breed called  the “Scottish Fold,” displays this phenotype in most breedings The gene for folded ears is dominant (E) and the gene for straight ears (e) is recessive. 

1.  Write the three genotypes that are possible (choose your letters) and describe their phenotypes.  Remember, genotypes have two letters and the phenotype describes what the cat looks like (folded or straight).







2.  Show the cross of two heterozygous cats.   What percentage of their offspring will have folded ears?







3.  A heterozygous cat is crossed with a cat that has straight ears.  What percentage of their offspring will have folded ears?








4.  If both parents have straight ears, What percentage of the kittens will have straight ears also?