Complete this Punnett Square. Imagine Brown Eyes (T) are dominant to blue eyes (t).

T
t
T

T

3 answers

To complete the Punnett Square for the eyes color (where Brown Eyes (T) are dominant to Blue Eyes (t)), we can set it up as follows:

Let's assume the parents' genotypes are:

  • One parent is homozygous dominant (TT)
  • The other parent is homozygous recessive (tt)

The Punnett Square will look like this:

       T    |    T
--------------------
   t |   Tt  |   Tt  
--------------------
   t |   Tt  |   Tt  

Interpretation:

  • All offspring will have the genotype Tt (heterozygous), which means they will all exhibit the dominant trait of brown eyes.

So, if one parent has brown eyes (homozygous TT) and the other has blue eyes (homozygous tt), all of their offspring will have brown eyes (Tt).

What is the percent chance (probability) of genotype TT?
What is the percent chance (probability) of genotype Tt?
What is the percent chance (probability) of genotype tt?
What is the probability of the phenotype of brown eyes?
What is the probability of the phenotype of blue eyes?

In the scenario where one parent is homozygous dominant (TT) for brown eyes and the other parent is homozygous recessive (tt) for blue eyes, the completed Punnett Square provides us with the following information:

       T    |    T
--------------------
   t |   Tt  |   Tt  
--------------------
   t |   Tt  |   Tt  

Probability of Genotypes:

  1. Probability of genotype TT (homozygous dominant):

    • Chance: 0%
  2. Probability of genotype Tt (heterozygous):

    • Chance: 100% (4 out of 4 squares are Tt)
  3. Probability of genotype tt (homozygous recessive):

    • Chance: 0%

Probability of Phenotypes:

  1. Probability of phenotype of brown eyes (T_):

    • Since all the offspring are Tt, they will all have brown eyes.
    • Chance: 100%
  2. Probability of phenotype of blue eyes (tt):

    • Since there are no tt offspring in this cross, the probability is 0%.
    • Chance: 0%

To summarize:

  • Probability of genotype TT: 0%
  • Probability of genotype Tt: 100%
  • Probability of genotype tt: 0%
  • Probability of phenotype brown eyes: 100%
  • Probability of phenotype blue eyes: 0%