Chapter 13, Problem 16P

Suppose polymerase chain reaction (PCR) is used toamplify a single DNA marker on human chromosome $\text{21}$. Further suppose that a couple who have a child with Downsyndrome (trisomy $\text{21}$) is examined for this marker. Themother has marker alleles of $\text{310}$ and $\text{380}$ bp. Her matehas marker alleles of $\text{290}$ and $\text{340}$ bp. What PCR bands arepresent in their child with Down syndrome if nondisjunction occurred in

maternal meiosis $\text{I}$

maternal meiosis $\text{II}$

paternal meiosis $\text{I}$

paternal meiosis $\text{II}$