Polydactyly is a genetic condition that involves the presence of extra number of toes or fingers in humans.
When one parent is normal and the other parent has an extra finger but is heterozygous for the trait, the probability that the first child will be normal will be 0.5
Let this trait be represented as P; normal: pp while heterozygous: Pp
Parent P p x p p
F1 Pp pp
Genotypic frequency: Pp : 50% ; pp: 50%
Therefore, the probability that their first child will be normal is 0.5
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