• A Punnett square is a chart that helps us predict the probability that an offspring with a particular genotype and phenotype will be

produced

I wish I could make a punnett square

• To make a Punnett square there are a few simple steps to follow:

 

1. Draw a box and divide it into four parts

2. Label the left hand side of the box with the genotype of one

parent (R=Red, r=White)

R

r

3. Label the top of the box with the genotype of the other parent

R

r

r r

4. In the middle boxes place 2 letters. One letter comes from the left side and one from the top

R

r

r r

Rr

rr

Rr

rr

• You now know the possible genotypes for the offspring of these two parents.

• The genotypes of the offspring are

• 0RR:2Rr: 2rr • The phenotypes of the offspring are • 2 Red: 2 White

1. A cross between a female with straight hair (HH) and a male with curly hair (hh)

 • genotypes___________(#HH:#Hh:#hh)• phenotypes__________(Straight:curly)

2. A cross between a black dog (Bb) and a brown dog (bb)

 

 • genotypes_____________

(#BB:#Bb:#bb)• phenotypes____________

(#Black:#Brown)

3. A cross between a yellow corn (Yy) and another yellow corn (Yy) (y = white corn)

 

   • genotypes_________________

(#YY:#Yy:#yy)• phenotypes________________

(# Yellow: # white)