Questions: Using the pedigree below, answer the remaining questions.

Transcript text: Using the pedigree below, answer the remaining questions.

Solution

Solution Steps

Step 1: Analyzing the Pedigree Chart for Mode of Inheritance

The filled-in squares and circles represent individuals affected by the trait. Since both males and females are affected equally, the trait is likely autosomal, not sex-linked. The trait appears in every generation, which suggests dominant inheritance rather than recessive.

Step 2: Determining the Genotypes of Individuals

Since the trait is autosomal dominant, affected individuals must have at least one dominant allele (represented as "A"). Unaffected individuals have two recessive alleles ("a"). III-1 (affected) and III-2 (unaffected) have a child (IV-1) whose status we need to determine. III-1, being affected, can have the genotype AA or Aa. III-2, being unaffected, must have the genotype aa.

Step 3: Punnett Square Analysis for IV-1

Scenario 1: III-1 is Aa

A Punnett square crossing Aa (III-1) and aa (III-2) yields offspring with a 50% chance of being Aa (affected) and a 50% chance of being aa (unaffected).

Scenario 2: III-1 is AA

A Punnett square crossing AA (III-1) and aa (III-2) yields all offspring with genotype Aa (all affected).

Final Answer:

There is at least a 50% chance, and possibly a 100% chance, that individual IV-1 will be affected, depending on the genotype of III-1. If III-1 is heterozygous (Aa), there is a 50% chance IV-1 will be affected. If III-1 is homozygous dominant (AA), there is a 100% chance IV-1 will be affected.

Was this solution helpful?

Unhelpful

Helpful

Questions asked by other users

< Previous Next >