Chapter 10, Problem 25P

A second strain of dwarf plants has a different mutation of the same gene identified in Problem $\text{24}$. In the second strain, plants carrying a copy of the mutant allele produce a DNA restriction fragment of $\text{10}\text{.5}$ kb, rather than the $\text{7}\text{.5-}$ kb fragment. DNA fragments produced by digestion of DNA from tall carrier plants are shown below in lanes $\text{1}$ and $\text{2}$, fragments from tall progeny of carriers are shown in lanes $\text{3}$ and $\text{4}$, and DNA from dwarf plants is shown in lane $\text{5}$.

What mutational mechanism is most likely responsible for the production of abnormal DNA fragment length corresponding to this mutant allele? Explain your reasoning.

In comparison to the length of mRNA from the normal allele, will the mRNA from this mutant allele most likely be longer, shorter, or about the same length? Explain your answer.