Chapter 15, Problem 19P

You have isolated a genomic clone with an EcoR $\text{I}$ fragment of $11$ kbthat encompasses the CRABS CLAW gene (see Problem $\text{18}$). You digest the genomic clone with Hind $\text{III}$ and note that the $\text{11-}$ kbEcoR $\text{I}$ fragment is split into three fragments of $9$ kb, $1.5$ kb, and $0.5$ kb.

Does this tell you anything about where the CRABS CLAW gene is located within the $\text{11-}$ kb genomic clone?

Restriction enzyme sites within a cDNA clone are often also in the genomic sequence. Can you think of a reason why occasionally this is not the case? What about the converse: Are restriction enzyme sites in a genomic clone always in a cDNA clone of the same gene?

To further analyze the CRABS CLAW gene (see Problems $19$ and $\text{20}$), you create a map of the genomic clone. The $\text{11-}$ kb EcoRI fragment is cloned into the EcoRI site of the MCS of the vector shown in Problem $18$. You digest the double $\text{-}$ stranded form of the genome with several restriction enzymes and obtain the following results. Draw, as far as possible, a map of the genomic clone of CRABS CLAW.

What restriction digest would help resolve any ambiguity in the map?