Question

both parents of a newborn are heterozygous for an autosomal dominant genetic disorder. what are the odds that the newborn would also display the disorder? 1/4 2/4 1/2 3/4

Explanation:

Step1: Set allele symbols

Let the dominant allele be \(A\) and the recessive allele be \(a\). Both parents are heterozygous, so their genotypes are \(Aa\).

Step2: Create Punnett - square

The possible gametes from each parent are \(A\) and \(a\). The Punnett - square has 4 possible combinations: \(AA\), \(Aa\), \(Aa\), \(aa\).

Step3: Determine affected genotypes

For an autosomal dominant disorder, genotypes \(AA\) and \(Aa\) will display the disorder. There are 3 out of 4 such genotypes (\(AA:Aa:Aa:aa = 1:2:1\)).

Answer:

3/4