Question

1. Give an example of two individuals who have the same phenotype, but different genotypes for the albinism gene. Explain how two individuals with the same phenotype can have different genotypes.

2. For the corresponding phenotypes, the fraction with normal pigment is ______ and the fraction with albinism is ______, so the corresponding ratio is ______.

3. Suppose a father has aa alleles and a mother has Aa alleles. Complete the Punnett Square to describe this mating and determine what fraction of this couple’s children would be expected to have albinism.

Answer 1

3.

1.Yes, an organism can have the same phenotype but different genotypes.
Genotype is the genetic makeup.
Phenotype is physical appearance.

Alleles are forms of a gene. ex. Brown eyes are dominant over blue eyes. Blue eyes are recessive.

Brown eyes(B) & Blue eyes (b)
Alleles can be
1) heterozygous alleles (hybrid) - different alleles ex. Bb
2) homozygous alleles (pure)- identical alleles ex. BB, bb

Genotypes
BB- homozygous brown eyes
Bb- heterozygous brown eyes
bb- blue eyes (homozygous)

Blue eyes can only be homozygous (bb).
Brown eyes can have the same phenotype but different genotypes. Brown eyes can be heterozygous (Bb) or homozygous (BB).

Basically, organisms with a dominant phenotype can have different genotypes (homozygous or heterozygous). Organisms with a recessive phenotype can only have a homozygous genotypes.

2.