If the recessive female from Generation III were to have offspring with a heterozygous male, what are the chances the offspring will have the recessive trait?

Question

25%
50%
75%
100%

Answer 1

To determine the chances of the offspring having the recessive trait when a recessive female from Generation III (we can denote her genotype as "aa") has offspring with a heterozygous male (we can denote his genotype as "Aa"), we can use a simple Punnett square.

• The recessive female (aa) can only pass on the recessive allele (a).
• The heterozygous male (Aa) can pass on either the dominant allele (A) or the recessive allele (a).

Setting up the Punnett square:

          A   |   a
      -----------------
    a |   Aa  |   aa
      -----------------
    a |   Aa  |   aa

From this Punnett square, we can see the potential offspring genotypes:

• 50% will be heterozygous (Aa) – they will not express the recessive trait.
• 50% will be homozygous recessive (aa) – they will express the recessive trait.

Therefore, the chances that the offspring will have the recessive trait are 50%.