T

G

A

C

T

T

T

C

C

C

C

G

G

A

A

A

A

A

C

T

G

A

A

A

G

G

G

G

C

C

T

T

T

T

To help remember the base pairings,

think of the phone

company, AT&T

1 2 3 4 5 6

7 8 9 10 11 12

13 14 15 16 17 18

19 20 21 22X Y

1 2 3 4 5 6

7 8 9 10 11 12

13 14 15 16 17 18

19 20 21 22X Y

Gene for Eye ColorGene for Hair Color

piece of DNA

piece of DNA

pair of chromosomes

1 2 3 4 5 6

7 8 9 10 11 12

13 14 15 16 17 18

19 20 21 22X Y

Gene for Eye ColorGene for

Eye Color

Mother’s Gene for Eye Color

Father’s Gene for Eye Color

Allele for brown eyes Allele for blue eyes

1 2 3 4 5 6

7 8 9 10 11 12

13 14 15 16 17 18

19 20 21 22X Y

Brown Brown Brown

Eye Color

blue Brown blue

Brown Eye Color?

Blue Eye Color?

Phenotype [Mendelian Inheritance]

The Dominant allele is the Capital Letter (“B”)

The Recessive allele is the Lowercase Letter (“b”)

B b Brown Eye Color Phenotype

B B Brown Eye Color Phenotype

B b Brown Eye Color Phenotype

B B Brown Eye Color Phenotype

Phenotype is Brown Eye Color

B b

Brown Eye Color isthe Dominant Allele

Phenotype is Brown Eye Color

B B

Brown Eye Color isthe Dominant Allele

b b Blue Eye Color Phenotype

Phenotype is Blue Eye Color

b b

Two Recessive AllelesFor Blue Eye Color