Heredity of Eye Color

The four variations of gene pairs for the brown/blue-eyed trait can be combined in ways that produce different probabilities of these traits in offspring. Drag different variations of gene pairs into the parent boxes and observe the results. The traditional explanation using Punnett squares is below.

 

Punnett Square

B=Dominant, b=Recessive

	B	b
B	BB	bB
b	Bb	bb

Individuals have a pair of each chromosome, thus two copies of the gene. An individual can have a genotype of:

• BB (Homozygous dominant)
• Bb (Heterozygous)
• bb (Homozygous Recessive)

Any of these individuals could mate with any other, to produce these possibilities:

B B B BB BB B BB BB	B B B BB BB b Bb Bb	B b B BB Bb b Bb bb
B b b Bb bb b Bb bb	b b b bb bb b bb bb	B B b Bb Bb b Bb Bb