Question

what percent chance does each offspring have of inheriting the trait when only one parent passes on the gene? what is the genotype of the individuals represented in the pedigree who do not inherit the trait?
key
□ male without trait
○ female without trait
■ male with trait
● female with trait
chance of inheriting the trait:
genotype of unaffected offspring:
25% gg
50% gg
100% gg
100% gg
50% gg
25% gg
50% gg

Explanation:

Step1: Assume single - gene inheritance

If only one parent passes on the gene, assuming the parent is heterozygous (Gg) and the other is homozygous recessive (gg) for a simple Mendelian trait. When a heterozygous (Gg) parent mates with a homozygous - recessive (gg) parent, the Punnett - square analysis is used.

Step2: Calculate inheritance probability

The cross Gg x gg gives two possible genotypes in offspring: Gg and gg in a 1:1 ratio. So the chance of inheriting the trait (having the dominant allele G) is 50%.

Step3: Determine genotype of unaffected offspring

Unaffected offspring have the recessive genotype. In this case, it is gg.

Answer:

50%, gg