A Dihybrid Testcross Is Made to Determine If Genes C

question 22

Multiple Choice

A dihybrid testcross is made to determine if genes C and D are linked.The results are shown in the table.
$\begin{array}{|l|c|r|}\hline \text { Parent genotypes: } & C c  D d \times c c d d & \\\hline & C c  D d & 222 \\\hline & C c  d d & 280 \\\hline \text { Progeny genotypes: } & c c  D d & 280 \\\hline & c c  d d & 218 \\\hline & & 1000 \\\hline\end{array}$
-The chi-square value is the sum for all progeny classes of (observed-expected) ²/expected.Using the chi-square test for goodness of fit, calculate the chi-square value to test the null hypothesis that genes C and D are unlinked.What is the chi-square value?

• A)0
• B)0.0576
• C)10.8
• D)14.4
• E)cannot be determined